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39 results on '"Linscott, I. R."'

1. A Near Surface Temperature Model of Arrokoth

Author: Umurhan, O. M., Grundy, W. M., Bird, M. K., Beyer, R., Keane, J. T., Linscott, I. R., Birch, S., Bierson, C., Young, L. A., Stern, S. A., Lisse, C. M., Howett, C. J. A., Protopapa, S., Spencer, J. R., Binzel, R. P., Mckinnon, W. B., Lauer, T. R., Weaver, H. A., Olkin, C. B., Singer, K. N., Verbiscer, A. J., Parker, A. H., Umurhan, O. M., Grundy, W. M., Bird, M. K., Beyer, R., Keane, J. T., Linscott, I. R., Birch, S., Bierson, C., Young, L. A., Stern, S. A., Lisse, C. M., Howett, C. J. A., Protopapa, S., Spencer, J. R., Binzel, R. P., Mckinnon, W. B., Lauer, T. R., Weaver, H. A., Olkin, C. B., Singer, K. N., Verbiscer, A. J., and Parker, A. H.
Abstract: A near surface thermal model for Arrokoth is developed based on the recently released $10^5$ facet model of the body. This thermal solution takes into account Arrokoth's surface re-radiation back onto itself. The solution method exploits Arrokoth's periodic orbital character to develop a thermal response using a time-asymptotic solution method, which involves a Fourier transform solution of the heat equation, an approach recently used by others. We display detailed thermal solutions assuming that Arrokoth's near surface material's thermal inertia ${\cal I} = $ 2.5 W/m$^{-2}$K$^{-1}$s$^{1/2}$. We predict that at New Horizons' encounter with Arrokoth its encounter hemisphere surface temperatures were $\sim$ 57-59 K in its polar regions, 30-40 K on its equatorial zones, and 11-13 K for its winter hemisphere. Arrokoth's orbitally averaged temperatures are around 30-35 K in its polar regions, and closer to 40 K near its equatorial zones. Thermal reradiation from the surrounding surface amounts to less than 5\% of the total energy budget, while the total energy ensconced into and exhumed out Arrokoth's interior via thermal conduction over one orbit is about 0.5\% of the total energy budget. As a generalized application of this thermal modeling together with other KBO origins considerations, we favor the interpretation that New Horizons' REX instrument's $29 \pm 5$K brightness temperature measurement is consistent with Arrokoth's near surface material's being made of sub-to-few mm sized tholin-coated amorphous \water ice grains with 1 W/m$^{-2}$K$^{-1}$s$^{1/2}$ $< {\cal I} < $10-20 W/m$^{-2}$K$^{-1}$s$^{1/2}$, and which are characterized by an X-band emissivity in the range 0.9 and 1., Comment: Accepted on Feb. 21, 2022 for publication in Planetary Science Journal (PSJ)
Published: 2022

2. A Predicted Dearth of Bulk Hypervolatile Ices in Oort Cloud Comets

Author: Lisse, C. M., Gladstone, G. R., Young, L. A., Cruikshank, D. P., Sandford, S. A., Schmitt, B., Stern, S. A., Weaver, H. A., Umurhan, O., Pendleton, Y. J., Keane, J. T., Parker, J. M., Binzel, R. P., Earle, A. M., Horanyi, M., El-Maarry, M., Cheng, A. F., Moore, J. M., McKinnon, W. B., Grundy, W. M., Kavelaars, J. J., Linscott, I. R., Lyra, W., Lewis, B. L., Britt, D. T., Spencer, J. R., Olkin, C. B., McNutt, R. L., Elliott, H. A., Dello-Russo, N., Steckloff, J. K., Neveu, M., Mousis, O., Lisse, C. M., Gladstone, G. R., Young, L. A., Cruikshank, D. P., Sandford, S. A., Schmitt, B., Stern, S. A., Weaver, H. A., Umurhan, O., Pendleton, Y. J., Keane, J. T., Parker, J. M., Binzel, R. P., Earle, A. M., Horanyi, M., El-Maarry, M., Cheng, A. F., Moore, J. M., McKinnon, W. B., Grundy, W. M., Kavelaars, J. J., Linscott, I. R., Lyra, W., Lewis, B. L., Britt, D. T., Spencer, J. R., Olkin, C. B., McNutt, R. L., Elliott, H. A., Dello-Russo, N., Steckloff, J. K., Neveu, M., and Mousis, O.
Abstract: We present new, ice species-specific New Horizons/Alice upper gas coma production limits from the 01 Jan 2019 MU69/Arrokoth flyby of Gladstone et al. (2021) and use them to make predictions about the rarity of majority hypervolatile (CO, N$_2$, CH$_4$) ices in KBOs and Oort Cloud comets. These predictions have a number of important implications for the study of the Oort Cloud, including: determination of hypervolatile rich comets as the first objects emplaced into the Oort Cloud; measurement of CO/N$_2$/CH$_4$ abundance ratios in the proto-planetary disk from hypervolatile rich comets; and population statistical constraints on early (< 20 Myr) planetary aggregation driven versus later (> 50 Myr) planetary migration driven emplacement of objects into the Oort Cloud. They imply that the phenomenon of ultra-distant active comets like C/2017K2 (Jewitt et al. 2017, Hui et al. 2018) should be rare, and thus not a general characteristic of all comets. They also suggest that interstellar object 2I/Borisov did not originate in a planetary system that was inordinately CO rich (Bodewits et al. 2020), but rather could have been ejected onto an interstellar trajectory very early in its natal system's history., Comment: 16 Pages, 2 Figures, 1 Table; accepted for Publication in PSJ 14-Mar-2022
Published: 2022

3. Detection of Radio Thermal Emission from the Kuiper Belt Object (486958) Arrokoth during the New Horizons Encounter

Author: Bird, M. K., Linscott, I. R., Tyler, G. L., Umurhan, O. M., Beyer, R. A., Grundy, W. M., Lisse, C. M., Hinson, D. P., Paetzold, M., Stern, S. A., Weaver, H. A., Olkin, C. B., Young, L. A., Spencer, J. R., Singer, K. N., Moore, J. M., Gladstone, G. R., DeBoy, C. C., Vincent, M., Porter, S. B., Bird, M. K., Linscott, I. R., Tyler, G. L., Umurhan, O. M., Beyer, R. A., Grundy, W. M., Lisse, C. M., Hinson, D. P., Paetzold, M., Stern, S. A., Weaver, H. A., Olkin, C. B., Young, L. A., Spencer, J. R., Singer, K. N., Moore, J. M., Gladstone, G. R., DeBoy, C. C., Vincent, M., and Porter, S. B.
Abstract: The New Horizons spacecraft encountered the Kuiper Belt object (KBO) Arrokoth (486958), originally designated as 2014 MU69 and formerly called Ultima Thule, on 2019 January 01. At 43.3 au from the Sun and 44.4 au from Earth, this was the most distant spacecraft reconnaissance of a solar system body to date. The Radio Science Experiment (REX) on New Horizons performed radiometry measurements of the KBO's thermal emission at lambda = 4.2 cm in two observation slots, one before (dayside) and one after (nightside) the point of closest approach. Owing to the small size of the target, the intensity of the thermal emission was expected to be only marginally detectable. The KBO was not detected on approach because of unexpectedly large variations in the REX system temperature. A brightness temperature T ( b ) = 29 +/- 5 K was derived for the nightside observation, considerably less than the predicted equilibrium temperature of similar to 50 K derived for Arrokoth on the dayside. A model explaining this day-night contrast is used to constrain the global values of emissivity, thermal inertia, and electrical skin depth of the KBO. In particular, models with small values of thermal inertia and small values of electrical skin depth are excluded. Relatively high values of the effective radio emissivity (E (eff) > 0.8) provide better agreement with the REX observation.
Published: 2022

4. A Predicted Dearth of Majority Hypervolatile Ices in Oort Cloud Comets

Author: Lisse, C. M., Gladstone, G. R., Young, L. A., Cruikshank, D. P., Sandford, S. A., Schmitt, B., Stern, S. A., Weaver, H. A., Umurhan, O., Pendleton, Y. J., Keane, J. T., Parker, J. M., Binzel, R. P., Earle, A. M., Horanyi, M., El-Maarry, M., Cheng, A. F., Moore, J. M., McKinnon, W. B., Grundy, W. M., Kavelaars, J. J., Linscott, I. R., Lyra, W., Lewis, B. L., Britt, D. T., Spencer, J. R., Olkin, C. B., McNutt, R. L., Elliott, H. A., Dello-Russo, N., Steckloff, J. K., Neveu, M., Mousis, O., Lisse, C. M., Gladstone, G. R., Young, L. A., Cruikshank, D. P., Sandford, S. A., Schmitt, B., Stern, S. A., Weaver, H. A., Umurhan, O., Pendleton, Y. J., Keane, J. T., Parker, J. M., Binzel, R. P., Earle, A. M., Horanyi, M., El-Maarry, M., Cheng, A. F., Moore, J. M., McKinnon, W. B., Grundy, W. M., Kavelaars, J. J., Linscott, I. R., Lyra, W., Lewis, B. L., Britt, D. T., Spencer, J. R., Olkin, C. B., McNutt, R. L., Elliott, H. A., Dello-Russo, N., Steckloff, J. K., Neveu, M., and Mousis, O.
Abstract: We present new, ice species-specific New Horizons/Alice upper gas coma production limits from the 01 Jan 2019 MU69/Arrokoth flyby of Gladstone et al. (2021) and use them to make predictions about the rarity of majority hypervolatile (CO, N$_2$, CH$_4$) ices in KBOs and Oort Cloud comets. These predictions have a number of important implications for the study of the Oort Cloud, including: determination of hypervolatile rich comets as the first objects emplaced into the Oort Cloud; measurement of CO/N$_2$/CH$_4$ abundance ratios in the proto-planetary disk from hypervolatile rich comets; and population statistical constraints on early (< 20 Myr) planetary aggregation driven versus later (> 50 Myr) planetary migration driven emplacement of objects into the Oort Cloud. They imply that the phenomenon of ultra-distant active comets like C/2017K2 (Jewitt et al. 2017, Hui et al. 2018) should be rare, and thus not a general characteristic of all comets. They also suggest that interstellar object 2I/Borisov did not originate in a planetary system that was inordinately CO rich (Bodewits et al. 2020), but rather could have been ejected onto an interstellar trajectory very early in its natal system's history., Comment: 16 Pages, 2 Figures, 1 Table; accepted for Publication in PSJ 14-Mar-2022
Published: 2022

5. A Near Surface Temperature Model of Arrokoth

Author: Umurhan, O. M., Grundy, W. M., Bird, M. K., Beyer, R., Keane, J. T., Linscott, I. R., Birch, S., Bierson, C., Young, L. A., Stern, S. A., Lisse, C. M., Howett, C. J. A., Protopapa, S., Spencer, J. R., Binzel, R. P., Mckinnon, W. B., Lauer, T. R., Weaver, H. A., Olkin, C. B., Singer, K. N., Verbiscer, A. J., Parker, A. H., Umurhan, O. M., Grundy, W. M., Bird, M. K., Beyer, R., Keane, J. T., Linscott, I. R., Birch, S., Bierson, C., Young, L. A., Stern, S. A., Lisse, C. M., Howett, C. J. A., Protopapa, S., Spencer, J. R., Binzel, R. P., Mckinnon, W. B., Lauer, T. R., Weaver, H. A., Olkin, C. B., Singer, K. N., Verbiscer, A. J., and Parker, A. H.
Abstract: A near surface thermal model for Arrokoth is developed based on the recently released $10^5$ facet model of the body. This thermal solution takes into account Arrokoth's surface re-radiation back onto itself. The solution method exploits Arrokoth's periodic orbital character to develop a thermal response using a time-asymptotic solution method, which involves a Fourier transform solution of the heat equation, an approach recently used by others. We display detailed thermal solutions assuming that Arrokoth's near surface material's thermal inertia ${\cal I} = $ 2.5 W/m$^{-2}$K$^{-1}$s$^{1/2}$. We predict that at New Horizons' encounter with Arrokoth its encounter hemisphere surface temperatures were $\sim$ 57-59 K in its polar regions, 30-40 K on its equatorial zones, and 11-13 K for its winter hemisphere. Arrokoth's orbitally averaged temperatures are around 30-35 K in its polar regions, and closer to 40 K near its equatorial zones. Thermal reradiation from the surrounding surface amounts to less than 5\% of the total energy budget, while the total energy ensconced into and exhumed out Arrokoth's interior via thermal conduction over one orbit is about 0.5\% of the total energy budget. As a generalized application of this thermal modeling together with other KBO origins considerations, we favor the interpretation that New Horizons' REX instrument's $29 \pm 5$K brightness temperature measurement is consistent with Arrokoth's near surface material's being made of sub-to-few mm sized tholin-coated amorphous \water ice grains with 1 W/m$^{-2}$K$^{-1}$s$^{1/2}$ $< {\cal I} < $10-20 W/m$^{-2}$K$^{-1}$s$^{1/2}$, and which are characterized by an X-band emissivity in the range 0.9 and 1., Comment: Accepted on Feb. 21, 2022 for publication in Planetary Science Journal (PSJ)
Published: 2022

6. Solar System Interiors, Atmospheres, and Surfaces Investigations via Radio Links: Goals for the Next Decade

Author: Massachusetts Institute of Technology. Department of Aeronautics and Astronautics, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Asmar, Sami, Preston, R. A., Vergados, P., Atkinson, D. H., Andert, T., Ando, H., Ao, C. O., Armstrong, J. W., Ashby, N., Barriot, J.-P., Beauchamp, P. M., Bell, D. J., Bender, P. L., Benedetto, M. Di, Bills, B. G., Bird, M. K., Bocanegra-Bahamon, T. M., Botteon, G. K., Bruinsma, S., Buccino, D. R., Cahoy, K. L., Cappuccio, P., Choudhary, R. K., Dehant, V., Dumoulin, C., Durante, D., Edwards, C. D., Elliott, H. M., Ely, T. A., Ermakov, A. I., Ferri, F., Flasar, F. M., French, R. G., Genova, A., Goossens, S. J., Häusler, B., Helled, R., Hinson, D. P., Hofstadter, M. D., Iess, L., Imamura, T., Jongeling, A. P., Karatekin, Ö., Kaspi, Y., Kobayashi, M. M., Komjathy, A., Konopliv, A. S., Kursinski, E. R., Lazio, T. J. W., Maistre, S. Le, Lemoine, F. G., Lillis, R. J., Linscott, I. R., Mannucci, A. J., Marouf, E. A., Marty, J.-C., Matousek, S. E., Matsumoto, K., Mazarico, E. M., Notaro, V., Parisi, M., Park, R. S., Pätzold, M., Peytaví, G. G., Pugh, M. P., Rennó, N. O., Rosenblatt, P., Serra, D., Simpson, R. A., Smith, D. E., Steffes, P. G., Tapley, B. D., Tellmann, S., Tortora, P., Turyshev, S. G., Hoolst, T. Van, Verma, A. K., Watkins, M. M., Williamson, W., Wieczorek, M. A., Withers, P., Yseboodt, M., Yu, N., Zannoni, M., Zuber, M. T., Massachusetts Institute of Technology. Department of Aeronautics and Astronautics, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Asmar, Sami, Preston, R. A., Vergados, P., Atkinson, D. H., Andert, T., Ando, H., Ao, C. O., Armstrong, J. W., Ashby, N., Barriot, J.-P., Beauchamp, P. M., Bell, D. J., Bender, P. L., Benedetto, M. Di, Bills, B. G., Bird, M. K., Bocanegra-Bahamon, T. M., Botteon, G. K., Bruinsma, S., Buccino, D. R., Cahoy, K. L., Cappuccio, P., Choudhary, R. K., Dehant, V., Dumoulin, C., Durante, D., Edwards, C. D., Elliott, H. M., Ely, T. A., Ermakov, A. I., Ferri, F., Flasar, F. M., French, R. G., Genova, A., Goossens, S. J., Häusler, B., Helled, R., Hinson, D. P., Hofstadter, M. D., Iess, L., Imamura, T., Jongeling, A. P., Karatekin, Ö., Kaspi, Y., Kobayashi, M. M., Komjathy, A., Konopliv, A. S., Kursinski, E. R., Lazio, T. J. W., Maistre, S. Le, Lemoine, F. G., Lillis, R. J., Linscott, I. R., Mannucci, A. J., Marouf, E. A., Marty, J.-C., Matousek, S. E., Matsumoto, K., Mazarico, E. M., Notaro, V., Parisi, M., Park, R. S., Pätzold, M., Peytaví, G. G., Pugh, M. P., Rennó, N. O., Rosenblatt, P., Serra, D., Simpson, R. A., Smith, D. E., Steffes, P. G., Tapley, B. D., Tellmann, S., Tortora, P., Turyshev, S. G., Hoolst, T. Van, Verma, A. K., Watkins, M. M., Williamson, W., Wieczorek, M. A., Withers, P., Yseboodt, M., Yu, N., Zannoni, M., and Zuber, M. T.
Published: 2022

7. High-resolution radiometry of Pluto at 4.2 cm with New Horizons

Author: Linscott, I. R., Bird, M. K., Hinson, D. P., Tyler, G. L., Stern, S. A., Vincent, M. A., DeBoy, C. C., Young, L. A., Beyer, R. A., Ennico, K., Moore, J. M., Gladstone, G. R., Olkin, C. B., Paetzold, M., Schenk, P. M., Strobel, D. F., Summers, M. E., Weaver, H. A., Grundy, W. M., Linscott, I. R., Bird, M. K., Hinson, D. P., Tyler, G. L., Stern, S. A., Vincent, M. A., DeBoy, C. C., Young, L. A., Beyer, R. A., Ennico, K., Moore, J. M., Gladstone, G. R., Olkin, C. B., Paetzold, M., Schenk, P. M., Strobel, D. F., Summers, M. E., Weaver, H. A., and Grundy, W. M.
Abstract: The radio thermal emission from Pluto was observed from the New Horizons spacecraft at a wavelength of 4.2 cm along two scans across the planetary disk shortly after closest approach to Pluto on 14 July 2015. The measurements were performed as part of the New Horizons Radio Science Experiment (REX) using the 2.1 m High Gain Antenna (HGA) and the spacecraft's X-Band receiver. The HGA boresight first scanned along a diametric chord across the Pluto disk and then reversed direction to traverse a chord that crossed close to Pluto's winter pole. The diametric scan reveals a hot spot on the Pluto nightside associated with an optically bright region centered roughly at the planetocentric coordinates 280 degrees E, 55 degrees S, imaged in 2002-03 with the Hubble Space Telescope. The nightside was also found to be warmer than the dayside during the polar scan. The highest emission was not observed at the maximum southern latitude, however, but rather near the outbound Pluto limb at lower latitude. The REX emission profile from the polar scan is qualitatively consistent with a bright U-shaped polar cap observed on Pluto's Charon-facing hemisphere during the recurring Pluto/Charon mutual events in the late 1980's. The REX radiometer measurements show distinct variations in microwave brightness that constrain volatile transport models and provide unique information on the thermal structure and composition on the regions in winter night during the New Horizons encounter at Pluto.
Published: 2021

8. High-resolution radiometry of Pluto at 4.2 cm with New Horizons

Author: Linscott, I. R., Bird, M. K., Hinson, D. P., Tyler, G. L., Stern, S. A., Vincent, M. A., DeBoy, C. C., Young, L. A., Beyer, R. A., Ennico, K., Moore, J. M., Gladstone, G. R., Olkin, C. B., Paetzold, M., Schenk, P. M., Strobel, D. F., Summers, M. E., Weaver, H. A., Grundy, W. M., Linscott, I. R., Bird, M. K., Hinson, D. P., Tyler, G. L., Stern, S. A., Vincent, M. A., DeBoy, C. C., Young, L. A., Beyer, R. A., Ennico, K., Moore, J. M., Gladstone, G. R., Olkin, C. B., Paetzold, M., Schenk, P. M., Strobel, D. F., Summers, M. E., Weaver, H. A., and Grundy, W. M.
Abstract: The radio thermal emission from Pluto was observed from the New Horizons spacecraft at a wavelength of 4.2 cm along two scans across the planetary disk shortly after closest approach to Pluto on 14 July 2015. The measurements were performed as part of the New Horizons Radio Science Experiment (REX) using the 2.1 m High Gain Antenna (HGA) and the spacecraft's X-Band receiver. The HGA boresight first scanned along a diametric chord across the Pluto disk and then reversed direction to traverse a chord that crossed close to Pluto's winter pole. The diametric scan reveals a hot spot on the Pluto nightside associated with an optically bright region centered roughly at the planetocentric coordinates 280 degrees E, 55 degrees S, imaged in 2002-03 with the Hubble Space Telescope. The nightside was also found to be warmer than the dayside during the polar scan. The highest emission was not observed at the maximum southern latitude, however, but rather near the outbound Pluto limb at lower latitude. The REX emission profile from the polar scan is qualitatively consistent with a bright U-shaped polar cap observed on Pluto's Charon-facing hemisphere during the recurring Pluto/Charon mutual events in the late 1980's. The REX radiometer measurements show distinct variations in microwave brightness that constrain volatile transport models and provide unique information on the thermal structure and composition on the regions in winter night during the New Horizons encounter at Pluto.
Published: 2021

9. Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt Object

Author: Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Carcich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horányi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kollmann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., McNutt, R. L., Mehoke, Jr. D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Núñez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Pätzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendall, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffl, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. R., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Weigle II, G. E., Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Winters, H. L., Zangari, A. M., Zurbuchen, T. H., Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Carcich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horányi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kollmann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., McNutt, R. L., Mehoke, Jr. D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Núñez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Pätzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendall, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffl, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. R., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Weigle II, G. E., Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Winters, H. L., Zangari, A. M., and Zurbuchen, T. H.
Abstract: The Kuiper Belt is a distant region of the Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a Cold Classical Kuiper Belt Object, a class of objects that have never been heated by the Sun and are therefore well preserved since their formation. Here we describe initial results from these encounter observations. MU69 is a bi-lobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color and compositional heterogeneity. No evidence for satellites, ring or dust structures, gas coma, or solar wind interactions was detected. By origin MU69 appears consistent with pebble cloud collapse followed by a low velocity merger of its two lobes., Comment: 43 pages, 8 figure
Published: 2020
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10. The Geology and Geophysics of Kuiper Belt Object (486958) Arrokoth

Author: Spencer, J. R., Stern, S. A., Moore, J. M., Weaver, H. A., Singer, K. N., Olkin, C. B., Verbiscer, A. J., McKinnon, W. B., Parker, J. Wm., Beyer, R. A., Keane, J. T., Lauer, T. R., Porter, S. B., White, O. L., Buratti, B. J., El-Maarry, M. R., Lisse, C. M., Parker, A. H., Throop, H. B., Robbins, S. J., Umurhan, O. M., Binzel, R. P., Britt, D. T., Buie, M. W., Cheng, A. F., Cruikshank, D. P., Elliott, H. A., Gladstone, G. R., Grundy, W. M., Hill, M. E., Horanyi, M., Jennings, D. E., Kavelaars, J. J., Linscott, I. R., McComas, D. J., McNutt, R. L., Protopapa, S., Reuter, D. C., Schenk, P. M., Showalter, M. R., Young, L. A., Zangari, A. M., Abedin, A. Y., Beddingfield, C. B., Benecchi, S. D., Bernardoni, E., Bierson, C. J., Borncamp, D., Bray, V. J., Chaikin, A. L., Dhingra, R. D., Fuentes, C., Fuse, T., Gay, P. L, Gwyn, S. D. J., Hamilton, D. P., Hofgartner, J. D., Holman, M. J., Howard, A. D., Howett, C. J. A., Karoji, H., Kaufmann, D. E., Kinczyk, M., May, B. H., Mountain, M., Pätzold, M., Petit, J. M., Piquette, M. R., Reid, I. N., Reitsema, H. J., Runyon, K. D., Sheppard, S. S., Stansberry, J. A., Stryk, T., Tanga, P., Tholen, D. J., Trilling, D. E., Wasserman, L. H., Spencer, J. R., Stern, S. A., Moore, J. M., Weaver, H. A., Singer, K. N., Olkin, C. B., Verbiscer, A. J., McKinnon, W. B., Parker, J. Wm., Beyer, R. A., Keane, J. T., Lauer, T. R., Porter, S. B., White, O. L., Buratti, B. J., El-Maarry, M. R., Lisse, C. M., Parker, A. H., Throop, H. B., Robbins, S. J., Umurhan, O. M., Binzel, R. P., Britt, D. T., Buie, M. W., Cheng, A. F., Cruikshank, D. P., Elliott, H. A., Gladstone, G. R., Grundy, W. M., Hill, M. E., Horanyi, M., Jennings, D. E., Kavelaars, J. J., Linscott, I. R., McComas, D. J., McNutt, R. L., Protopapa, S., Reuter, D. C., Schenk, P. M., Showalter, M. R., Young, L. A., Zangari, A. M., Abedin, A. Y., Beddingfield, C. B., Benecchi, S. D., Bernardoni, E., Bierson, C. J., Borncamp, D., Bray, V. J., Chaikin, A. L., Dhingra, R. D., Fuentes, C., Fuse, T., Gay, P. L, Gwyn, S. D. J., Hamilton, D. P., Hofgartner, J. D., Holman, M. J., Howard, A. D., Howett, C. J. A., Karoji, H., Kaufmann, D. E., Kinczyk, M., May, B. H., Mountain, M., Pätzold, M., Petit, J. M., Piquette, M. R., Reid, I. N., Reitsema, H. J., Runyon, K. D., Sheppard, S. S., Stansberry, J. A., Stryk, T., Tanga, P., Tholen, D. J., Trilling, D. E., and Wasserman, L. H.
Abstract: The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, are primitive objects preserving information about Solar System formation. The New Horizons spacecraft flew past one of these objects, the 36 km long contact binary (486958) Arrokoth (2014 MU69), in January 2019. Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters diameter) within a radius of 8000 km, and has a lightly-cratered smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.
Published: 2020
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11. Color, Composition, and Thermal Environment of Kuiper Belt Object (486958) Arrokoth

Author: Grundy, W. M., Bird, M. K., Britt, D. T., Cook, J. C., Cruikshank, D. P., Howett, C. J. A., Krijt, S., Linscott, I. R., Olkin, C. B., Parker, A. H., Protopapa, S., Ruaud, M., Umurhan, O. M., Young, L. A., Ore, C. M. Dalle, Kavelaars, J. J., Keane, J. T., Pendleton, Y. J., Porter, S. B., Scipioni, F., Spencer, J. R., Stern, S. A., Verbiscer, A. J., Weaver, H. A., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A., Earle, A. M., Elliott, H. A., Gabasova, L., Gladstone, G. R., Hill, M. E., Horanyi, M., Jennings, D. E., Lunsford, A. W., McComas, D. J., McKinnon, W. B., McNutt Jr., R. L., Moore, J. M., Parker, J. W., Quirico, E., Reuter, D. C., Schenk, P. M., Schmitt, B., Showalter, M. R., Singer, K. N., Weigle II, G. E., Zangari, A. M., Grundy, W. M., Bird, M. K., Britt, D. T., Cook, J. C., Cruikshank, D. P., Howett, C. J. A., Krijt, S., Linscott, I. R., Olkin, C. B., Parker, A. H., Protopapa, S., Ruaud, M., Umurhan, O. M., Young, L. A., Ore, C. M. Dalle, Kavelaars, J. J., Keane, J. T., Pendleton, Y. J., Porter, S. B., Scipioni, F., Spencer, J. R., Stern, S. A., Verbiscer, A. J., Weaver, H. A., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A., Earle, A. M., Elliott, H. A., Gabasova, L., Gladstone, G. R., Hill, M. E., Horanyi, M., Jennings, D. E., Lunsford, A. W., McComas, D. J., McKinnon, W. B., McNutt Jr., R. L., Moore, J. M., Parker, J. W., Quirico, E., Reuter, D. C., Schenk, P. M., Schmitt, B., Showalter, M. R., Singer, K. N., Weigle II, G. E., and Zangari, A. M.
Abstract: The outer Solar System object (486958) Arrokoth (provisional designation 2014 MU$_{69}$) has been largely undisturbed since its formation. We study its surface composition using data collected by the New Horizons spacecraft. Methanol ice is present along with organic material, which may have formed through radiation of simple molecules. Water ice was not detected. This composition indicates hydrogenation of carbon monoxide-rich ice and/ or energetic processing of methane condensed on water ice grains in the cold, outer edge of the early Solar System. There are only small regional variations in color and spectra across the surface, suggesting Arrokoth formed from a homogeneous or well-mixed reservoir of solids. Microwave thermal emission from the winter night side is consistent with a mean brightness temperature of 29$\pm$5 K., Comment: 31 pages, 8 figures
Published: 2020
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12. The geology and geophysics of Kuiper Belt object (486958) Arrokoth

Author: Spencer, J. R., Stern, S. A., Moore, J. M., Weaver, H. A., Singer, K. N., Olkin, C. B., Verbiscer, A. J., McKinnon, W. B., Parker, J. Wm., Beyer, R. A., Keane, J. T., Lauer, T. R., Porter, S. B., White, O. L., Buratti, B. J., El-Maarry, M. R., Lisse, C. M., Parker, A. H., Throop, H. B., Robbins, S. J., Umurhan, O. M., Binzel, R. P., Britt, D. T., Buie, M. W., Cheng, A. F., Cruikshank, D. P., Elliott, H. A., Gladstone, G. R., Grundy, W. M., Hill, M. E., Horanyi, M., Jennings, D. E., Kavelaars, J. J., Linscott, I. R., McComas, D. J., McNutt, R. L., Jr., Protopapa, S., Reuter, D. C., Schenk, P. M., Showalter, M. R., Young, L. A., Zangari, A. M., Abedin, A. Y., Beddingfield, C. B., Benecchi, S. D., Bernardoni, E., Bierson, C. J., Borncamp, D., Bray, V. J., Chaikin, A. L., Dhingra, R. D., Fuentes, C., Fuse, T., Gay, P. L., Gwyn, S. D. J., Hamilton, D. P., Hofgartner, J. D., Holman, M. J., Howard, A. D., Howett, C. J. A., Karoji, H., Kaufmann, D. E., Kinczyk, M., May, B. H., Mountain, M., Patzold, M., Petit, J. M., Piquette, M. R., Reid, I. N., Reitsema, H. J., Runyon, K. D., Sheppard, S. S., Stansberry, J. A., Stryk, T., Tanga, P., Tholen, D. J., Trilling, D. E., Wasserman, L. H., Spencer, J. R., Stern, S. A., Moore, J. M., Weaver, H. A., Singer, K. N., Olkin, C. B., Verbiscer, A. J., McKinnon, W. B., Parker, J. Wm., Beyer, R. A., Keane, J. T., Lauer, T. R., Porter, S. B., White, O. L., Buratti, B. J., El-Maarry, M. R., Lisse, C. M., Parker, A. H., Throop, H. B., Robbins, S. J., Umurhan, O. M., Binzel, R. P., Britt, D. T., Buie, M. W., Cheng, A. F., Cruikshank, D. P., Elliott, H. A., Gladstone, G. R., Grundy, W. M., Hill, M. E., Horanyi, M., Jennings, D. E., Kavelaars, J. J., Linscott, I. R., McComas, D. J., McNutt, R. L., Jr., Protopapa, S., Reuter, D. C., Schenk, P. M., Showalter, M. R., Young, L. A., Zangari, A. M., Abedin, A. Y., Beddingfield, C. B., Benecchi, S. D., Bernardoni, E., Bierson, C. J., Borncamp, D., Bray, V. J., Chaikin, A. L., Dhingra, R. D., Fuentes, C., Fuse, T., Gay, P. L., Gwyn, S. D. J., Hamilton, D. P., Hofgartner, J. D., Holman, M. J., Howard, A. D., Howett, C. J. A., Karoji, H., Kaufmann, D. E., Kinczyk, M., May, B. H., Mountain, M., Patzold, M., Petit, J. M., Piquette, M. R., Reid, I. N., Reitsema, H. J., Runyon, K. D., Sheppard, S. S., Stansberry, J. A., Stryk, T., Tanga, P., Tholen, D. J., Trilling, D. E., and Wasserman, L. H.
Abstract: The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU69). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.
Published: 2020

13. Color, composition, and thermal environment of Kuiper Belt object (486958) Arrokoth

Author: Grundy, W. M., Bird, M. K., Britt, D. T., Cook, J. C., Cruikshank, D. P., Howett, C. J. A., Krijt, S., Linscott, I. R., Olkin, C. B., Parker, A. H., Protopapa, S., Ruaud, M., Umurhan, O. M., Young, L. A., Ore, C. M. Dalle, Kavelaars, J. J., Keane, J. T., Pendleton, Y. J., Porter, S. B., Scipioni, F., Spencer, J. R., Stern, S. A., Verbiscer, A. J., Weaver, H. A., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A., Earle, A. M., Elliott, H. A., Gabasova, L., Gladstone, G. R., Hill, M. E., Horanyi, M., Jennings, D. E., Lunsford, A. W., McComas, D. J., McKinnon, W. B., McNutt, R. L., Jr., Moore, J. M., Parker, J. W., Quirico, E., Reuter, D. C., Schenk, P. M., Schmitt, B., Showalter, M. R., Singer, K. N., Weigle, G. E., II, Zangari, A. M., Grundy, W. M., Bird, M. K., Britt, D. T., Cook, J. C., Cruikshank, D. P., Howett, C. J. A., Krijt, S., Linscott, I. R., Olkin, C. B., Parker, A. H., Protopapa, S., Ruaud, M., Umurhan, O. M., Young, L. A., Ore, C. M. Dalle, Kavelaars, J. J., Keane, J. T., Pendleton, Y. J., Porter, S. B., Scipioni, F., Spencer, J. R., Stern, S. A., Verbiscer, A. J., Weaver, H. A., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A., Earle, A. M., Elliott, H. A., Gabasova, L., Gladstone, G. R., Hill, M. E., Horanyi, M., Jennings, D. E., Lunsford, A. W., McComas, D. J., McKinnon, W. B., McNutt, R. L., Jr., Moore, J. M., Parker, J. W., Quirico, E., Reuter, D. C., Schenk, P. M., Schmitt, B., Showalter, M. R., Singer, K. N., Weigle, G. E., II, and Zangari, A. M.
Abstract: The outer Solar System object (486958) Arrokoth (provisional designation 2014 MU69) has been largely undisturbed since its formation. We studied its surface composition using data collected by the New Horizons spacecraft. Methanol ice is present along with organic material, which may have formed through irradiation of simple molecules. Water ice was not detected. This composition indicates hydrogenation of carbon monoxide-rich ice and/or energetic processing of methane condensed on water ice grains in the cold, outer edge of the early Solar System. There are only small regional variations in color and spectra across the surface, which suggests that Arrokoth formed from a homogeneous or well-mixed reservoir of solids. Microwave thermal emission from the winter night side is consistent with a mean brightness temperature of 29 +/- 5 kelvin.
Published: 2020

14. Color, composition, and thermal environment of Kuiper Belt object (486958) Arrokoth

Author: Grundy, W. M., Bird, M. K., Britt, D. T., Cook, J. C., Cruikshank, D. P., Howett, C. J. A., Krijt, S., Linscott, I. R., Olkin, C. B., Parker, A. H., Protopapa, S., Ruaud, M., Umurhan, O. M., Young, L. A., Ore, C. M. Dalle, Kavelaars, J. J., Keane, J. T., Pendleton, Y. J., Porter, S. B., Scipioni, F., Spencer, J. R., Stern, S. A., Verbiscer, A. J., Weaver, H. A., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A., Earle, A. M., Elliott, H. A., Gabasova, L., Gladstone, G. R., Hill, M. E., Horanyi, M., Jennings, D. E., Lunsford, A. W., McComas, D. J., McKinnon, W. B., McNutt, R. L., Jr., Moore, J. M., Parker, J. W., Quirico, E., Reuter, D. C., Schenk, P. M., Schmitt, B., Showalter, M. R., Singer, K. N., Weigle, G. E., II, Zangari, A. M., Grundy, W. M., Bird, M. K., Britt, D. T., Cook, J. C., Cruikshank, D. P., Howett, C. J. A., Krijt, S., Linscott, I. R., Olkin, C. B., Parker, A. H., Protopapa, S., Ruaud, M., Umurhan, O. M., Young, L. A., Ore, C. M. Dalle, Kavelaars, J. J., Keane, J. T., Pendleton, Y. J., Porter, S. B., Scipioni, F., Spencer, J. R., Stern, S. A., Verbiscer, A. J., Weaver, H. A., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A., Earle, A. M., Elliott, H. A., Gabasova, L., Gladstone, G. R., Hill, M. E., Horanyi, M., Jennings, D. E., Lunsford, A. W., McComas, D. J., McKinnon, W. B., McNutt, R. L., Jr., Moore, J. M., Parker, J. W., Quirico, E., Reuter, D. C., Schenk, P. M., Schmitt, B., Showalter, M. R., Singer, K. N., Weigle, G. E., II, and Zangari, A. M.
Abstract: The outer Solar System object (486958) Arrokoth (provisional designation 2014 MU69) has been largely undisturbed since its formation. We studied its surface composition using data collected by the New Horizons spacecraft. Methanol ice is present along with organic material, which may have formed through irradiation of simple molecules. Water ice was not detected. This composition indicates hydrogenation of carbon monoxide-rich ice and/or energetic processing of methane condensed on water ice grains in the cold, outer edge of the early Solar System. There are only small regional variations in color and spectra across the surface, which suggests that Arrokoth formed from a homogeneous or well-mixed reservoir of solids. Microwave thermal emission from the winter night side is consistent with a mean brightness temperature of 29 +/- 5 kelvin.
Published: 2020

15. The geology and geophysics of Kuiper Belt object (486958) Arrokoth

Author: Spencer, J. R., Stern, S. A., Moore, J. M., Weaver, H. A., Singer, K. N., Olkin, C. B., Verbiscer, A. J., McKinnon, W. B., Parker, J. Wm., Beyer, R. A., Keane, J. T., Lauer, T. R., Porter, S. B., White, O. L., Buratti, B. J., El-Maarry, M. R., Lisse, C. M., Parker, A. H., Throop, H. B., Robbins, S. J., Umurhan, O. M., Binzel, R. P., Britt, D. T., Buie, M. W., Cheng, A. F., Cruikshank, D. P., Elliott, H. A., Gladstone, G. R., Grundy, W. M., Hill, M. E., Horanyi, M., Jennings, D. E., Kavelaars, J. J., Linscott, I. R., McComas, D. J., McNutt, R. L., Jr., Protopapa, S., Reuter, D. C., Schenk, P. M., Showalter, M. R., Young, L. A., Zangari, A. M., Abedin, A. Y., Beddingfield, C. B., Benecchi, S. D., Bernardoni, E., Bierson, C. J., Borncamp, D., Bray, V. J., Chaikin, A. L., Dhingra, R. D., Fuentes, C., Fuse, T., Gay, P. L., Gwyn, S. D. J., Hamilton, D. P., Hofgartner, J. D., Holman, M. J., Howard, A. D., Howett, C. J. A., Karoji, H., Kaufmann, D. E., Kinczyk, M., May, B. H., Mountain, M., Patzold, M., Petit, J. M., Piquette, M. R., Reid, I. N., Reitsema, H. J., Runyon, K. D., Sheppard, S. S., Stansberry, J. A., Stryk, T., Tanga, P., Tholen, D. J., Trilling, D. E., Wasserman, L. H., Spencer, J. R., Stern, S. A., Moore, J. M., Weaver, H. A., Singer, K. N., Olkin, C. B., Verbiscer, A. J., McKinnon, W. B., Parker, J. Wm., Beyer, R. A., Keane, J. T., Lauer, T. R., Porter, S. B., White, O. L., Buratti, B. J., El-Maarry, M. R., Lisse, C. M., Parker, A. H., Throop, H. B., Robbins, S. J., Umurhan, O. M., Binzel, R. P., Britt, D. T., Buie, M. W., Cheng, A. F., Cruikshank, D. P., Elliott, H. A., Gladstone, G. R., Grundy, W. M., Hill, M. E., Horanyi, M., Jennings, D. E., Kavelaars, J. J., Linscott, I. R., McComas, D. J., McNutt, R. L., Jr., Protopapa, S., Reuter, D. C., Schenk, P. M., Showalter, M. R., Young, L. A., Zangari, A. M., Abedin, A. Y., Beddingfield, C. B., Benecchi, S. D., Bernardoni, E., Bierson, C. J., Borncamp, D., Bray, V. J., Chaikin, A. L., Dhingra, R. D., Fuentes, C., Fuse, T., Gay, P. L., Gwyn, S. D. J., Hamilton, D. P., Hofgartner, J. D., Holman, M. J., Howard, A. D., Howett, C. J. A., Karoji, H., Kaufmann, D. E., Kinczyk, M., May, B. H., Mountain, M., Patzold, M., Petit, J. M., Piquette, M. R., Reid, I. N., Reitsema, H. J., Runyon, K. D., Sheppard, S. S., Stansberry, J. A., Stryk, T., Tanga, P., Tholen, D. J., Trilling, D. E., and Wasserman, L. H.
Abstract: The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU69). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.
Published: 2020

16. On the Origin and Thermal Stability of Arrokoths and Plutos Ices

Author: Lisse, C. M., Young, L. A., Cruikshank, D. P., Sandford, S. A., Schmitt, B., Stern, S. A., Weaver, H. A., Umurhan, O., Pendleton, Y. J., Keane, J. T., Gladstone, G. R., Parker, J. M., Binzel, R. P., Earle, A. M., Horanyi, M., El-Maarry, M., Cheng, A. F., Moore, J. M., McKinnon, W. B., Grundy, W. M., Kavelaars, J. J., Linscott, I. R., Lyra, W., Lewis, B. L., Britt, D. T., Spencer, J. R., Olkin, C. B., McNutt, R. L., Elliott, H. A., Dello-Russo, N., Steckloff, J. K., Neveu, M., Mousis, O., Lisse, C. M., Young, L. A., Cruikshank, D. P., Sandford, S. A., Schmitt, B., Stern, S. A., Weaver, H. A., Umurhan, O., Pendleton, Y. J., Keane, J. T., Gladstone, G. R., Parker, J. M., Binzel, R. P., Earle, A. M., Horanyi, M., El-Maarry, M., Cheng, A. F., Moore, J. M., McKinnon, W. B., Grundy, W. M., Kavelaars, J. J., Linscott, I. R., Lyra, W., Lewis, B. L., Britt, D. T., Spencer, J. R., Olkin, C. B., McNutt, R. L., Elliott, H. A., Dello-Russo, N., Steckloff, J. K., Neveu, M., and Mousis, O.
Abstract: We discuss in a thermodynamic, geologically empirical way the long-term nature of the stable majority ices that could be present in Kuiper Belt Object 2014 MU69 after its 4.6 Gyr residence in the EKB as a cold classical object. Considering the stability versus sublimation into vacuum for the suite of ices commonly found on comets, Centaurs, and KBOs at the average ~40K sunlit surface temperature of MU69 over Myr to Gyr, we find only 3 common ices that are truly refractory: HCN, CH3OH, and H2O (in order of increasing stability). NH3 and H2CO ices are marginally stable and may be removed by any positive temperature excursions in the EKB, as produced every 1e8 - 1e9 yrs by nearby supernovae and passing O/B stars. To date the NH team has reported the presence of abundant CH3OH and evidence for H2O on MU69s surface (Lisse et al. 2017, Grundy et al. 2020). NH3 has been searched for, but not found. We predict that future absorption feature detections will be due to an HCN or poly-H2CO based species. Consideration of the conditions present in the EKB region during the formation era of MU69 lead us to infer that it formed "in the dark", in an optically thick mid-plane, unable to see the nascent, variable, highly luminous Young Stellar Object-TTauri Sun, and that KBOs contain HCN and CH3OH ice phases in addition to the H2O ice phases found in their Short Period comet descendants. Finally, when we apply our ice thermal stability analysis to bodies/populations related to MU69, we find that methanol ice may be ubiquitous in the outer solar system; that if Pluto is not a fully differentiated body, then it must have gained its hypervolatile ices from proto-planetary disk sources in the first few Myr of the solar systems existence; and that hypervolatile rich, highly primordial comet C/2016 R2 was placed onto an Oort Cloud orbit on a similar timescale., Comment: 34 Pages, 5 Figures, 2 SOM Tables
Published: 2020
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17. The Geology and Geophysics of Kuiper Belt Object (486958) Arrokoth

Author: Spencer, J. R., Stern, S. A., Moore, J. M., Weaver, H. A., Singer, K. N., Olkin, C. B., Verbiscer, A. J., McKinnon, W. B., Parker, J. Wm., Beyer, R. A., Keane, J. T., Lauer, T. R., Porter, S. B., White, O. L., Buratti, B. J., El-Maarry, M. R., Lisse, C. M., Parker, A. H., Throop, H. B., Robbins, S. J., Umurhan, O. M., Binzel, R. P., Britt, D. T., Buie, M. W., Cheng, A. F., Cruikshank, D. P., Elliott, H. A., Gladstone, G. R., Grundy, W. M., Hill, M. E., Horanyi, M., Jennings, D. E., Kavelaars, J. J., Linscott, I. R., McComas, D. J., McNutt, R. L., Protopapa, S., Reuter, D. C., Schenk, P. M., Showalter, M. R., Young, L. A., Zangari, A. M., Abedin, A. Y., Beddingfield, C. B., Benecchi, S. D., Bernardoni, E., Bierson, C. J., Borncamp, D., Bray, V. J., Chaikin, A. L., Dhingra, R. D., Fuentes, C., Fuse, T., Gay, P. L, Gwyn, S. D. J., Hamilton, D. P., Hofgartner, J. D., Holman, M. J., Howard, A. D., Howett, C. J. A., Karoji, H., Kaufmann, D. E., Kinczyk, M., May, B. H., Mountain, M., Pätzold, M., Petit, J. M., Piquette, M. R., Reid, I. N., Reitsema, H. J., Runyon, K. D., Sheppard, S. S., Stansberry, J. A., Stryk, T., Tanga, P., Tholen, D. J., Trilling, D. E., Wasserman, L. H., Spencer, J. R., Stern, S. A., Moore, J. M., Weaver, H. A., Singer, K. N., Olkin, C. B., Verbiscer, A. J., McKinnon, W. B., Parker, J. Wm., Beyer, R. A., Keane, J. T., Lauer, T. R., Porter, S. B., White, O. L., Buratti, B. J., El-Maarry, M. R., Lisse, C. M., Parker, A. H., Throop, H. B., Robbins, S. J., Umurhan, O. M., Binzel, R. P., Britt, D. T., Buie, M. W., Cheng, A. F., Cruikshank, D. P., Elliott, H. A., Gladstone, G. R., Grundy, W. M., Hill, M. E., Horanyi, M., Jennings, D. E., Kavelaars, J. J., Linscott, I. R., McComas, D. J., McNutt, R. L., Protopapa, S., Reuter, D. C., Schenk, P. M., Showalter, M. R., Young, L. A., Zangari, A. M., Abedin, A. Y., Beddingfield, C. B., Benecchi, S. D., Bernardoni, E., Bierson, C. J., Borncamp, D., Bray, V. J., Chaikin, A. L., Dhingra, R. D., Fuentes, C., Fuse, T., Gay, P. L, Gwyn, S. D. J., Hamilton, D. P., Hofgartner, J. D., Holman, M. J., Howard, A. D., Howett, C. J. A., Karoji, H., Kaufmann, D. E., Kinczyk, M., May, B. H., Mountain, M., Pätzold, M., Petit, J. M., Piquette, M. R., Reid, I. N., Reitsema, H. J., Runyon, K. D., Sheppard, S. S., Stansberry, J. A., Stryk, T., Tanga, P., Tholen, D. J., Trilling, D. E., and Wasserman, L. H.
Abstract: The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, are primitive objects preserving information about Solar System formation. The New Horizons spacecraft flew past one of these objects, the 36 km long contact binary (486958) Arrokoth (2014 MU69), in January 2019. Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters diameter) within a radius of 8000 km, and has a lightly-cratered smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.
Published: 2020
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18. Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt Object

Author: Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Carcich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horányi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kollmann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., McNutt, R. L., Mehoke, Jr. D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Núñez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Pätzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendall, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffl, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. R., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Weigle II, G. E., Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Winters, H. L., Zangari, A. M., Zurbuchen, T. H., Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Carcich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horányi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kollmann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., McNutt, R. L., Mehoke, Jr. D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Núñez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Pätzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendall, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffl, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. R., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Weigle II, G. E., Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Winters, H. L., Zangari, A. M., and Zurbuchen, T. H.
Abstract: The Kuiper Belt is a distant region of the Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a Cold Classical Kuiper Belt Object, a class of objects that have never been heated by the Sun and are therefore well preserved since their formation. Here we describe initial results from these encounter observations. MU69 is a bi-lobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color and compositional heterogeneity. No evidence for satellites, ring or dust structures, gas coma, or solar wind interactions was detected. By origin MU69 appears consistent with pebble cloud collapse followed by a low velocity merger of its two lobes., Comment: 43 pages, 8 figure
Published: 2020
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19. Color, Composition, and Thermal Environment of Kuiper Belt Object (486958) Arrokoth

Author: Grundy, W. M., Bird, M. K., Britt, D. T., Cook, J. C., Cruikshank, D. P., Howett, C. J. A., Krijt, S., Linscott, I. R., Olkin, C. B., Parker, A. H., Protopapa, S., Ruaud, M., Umurhan, O. M., Young, L. A., Ore, C. M. Dalle, Kavelaars, J. J., Keane, J. T., Pendleton, Y. J., Porter, S. B., Scipioni, F., Spencer, J. R., Stern, S. A., Verbiscer, A. J., Weaver, H. A., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A., Earle, A. M., Elliott, H. A., Gabasova, L., Gladstone, G. R., Hill, M. E., Horanyi, M., Jennings, D. E., Lunsford, A. W., McComas, D. J., McKinnon, W. B., McNutt Jr., R. L., Moore, J. M., Parker, J. W., Quirico, E., Reuter, D. C., Schenk, P. M., Schmitt, B., Showalter, M. R., Singer, K. N., Weigle II, G. E., Zangari, A. M., Grundy, W. M., Bird, M. K., Britt, D. T., Cook, J. C., Cruikshank, D. P., Howett, C. J. A., Krijt, S., Linscott, I. R., Olkin, C. B., Parker, A. H., Protopapa, S., Ruaud, M., Umurhan, O. M., Young, L. A., Ore, C. M. Dalle, Kavelaars, J. J., Keane, J. T., Pendleton, Y. J., Porter, S. B., Scipioni, F., Spencer, J. R., Stern, S. A., Verbiscer, A. J., Weaver, H. A., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A., Earle, A. M., Elliott, H. A., Gabasova, L., Gladstone, G. R., Hill, M. E., Horanyi, M., Jennings, D. E., Lunsford, A. W., McComas, D. J., McKinnon, W. B., McNutt Jr., R. L., Moore, J. M., Parker, J. W., Quirico, E., Reuter, D. C., Schenk, P. M., Schmitt, B., Showalter, M. R., Singer, K. N., Weigle II, G. E., and Zangari, A. M.
Abstract: The outer Solar System object (486958) Arrokoth (provisional designation 2014 MU$_{69}$) has been largely undisturbed since its formation. We study its surface composition using data collected by the New Horizons spacecraft. Methanol ice is present along with organic material, which may have formed through radiation of simple molecules. Water ice was not detected. This composition indicates hydrogenation of carbon monoxide-rich ice and/ or energetic processing of methane condensed on water ice grains in the cold, outer edge of the early Solar System. There are only small regional variations in color and spectra across the surface, suggesting Arrokoth formed from a homogeneous or well-mixed reservoir of solids. Microwave thermal emission from the winter night side is consistent with a mean brightness temperature of 29$\pm$5 K., Comment: 31 pages, 8 figures
Published: 2020
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20. Pluto's Haze as a Surface Material

Author: Grundy, W. M., Bertrand, T., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A. F., Cook, J. C., Cruikshank, D. P., Devins, S. L., Ore, C. M. Dalle, Earle, A. M., Ennico, K., Forget, F., Gao, P., Gladstone1, G. R., Howett, C. J. A., Jennings, D. E., Kammer, J. A., Lauer, T. R., Linscott, I. R., Lisse, C. M., Lunsford, A. W., McKinnon, W. B., Olkin, C. B., Parker, A. H., Protopapa, S., Quirico, E., Reuter, D. C., Schmitt, B., Singer, K. N., Spencer, J. A., Stern, S. A., Strobel, D. F., Summers, M. E., Weaver, H. A., Weigle II, G. E., Wong, M. L., Young, E. F., Young, L. A., Zhang, X., Grundy, W. M., Bertrand, T., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A. F., Cook, J. C., Cruikshank, D. P., Devins, S. L., Ore, C. M. Dalle, Earle, A. M., Ennico, K., Forget, F., Gao, P., Gladstone1, G. R., Howett, C. J. A., Jennings, D. E., Kammer, J. A., Lauer, T. R., Linscott, I. R., Lisse, C. M., Lunsford, A. W., McKinnon, W. B., Olkin, C. B., Parker, A. H., Protopapa, S., Quirico, E., Reuter, D. C., Schmitt, B., Singer, K. N., Spencer, J. A., Stern, S. A., Strobel, D. F., Summers, M. E., Weaver, H. A., Weigle II, G. E., Wong, M. L., Young, E. F., Young, L. A., and Zhang, X.
Abstract: Pluto's atmospheric haze settles out rapidly compared with geological timescales. It needs to be accounted for as a surface material, distinct from Pluto's icy bedrock and from the volatile ices that migrate via sublimation and condensation on seasonal timescales. This paper explores how a steady supply of atmospheric haze might affect three distinct provinces on Pluto. We pose the question of why they each look so different from one another if the same haze material is settling out onto all of them. Cthulhu is a more ancient region with comparatively little present-day geological activity, where the haze appears to simply accumulate over time. Sputnik Planitia is a very active region where glacial convection, as well as sublimation and condensation rapidly refresh the surface, hiding recently deposited haze from view. Lowell Regio is a region of intermediate age featuring very distinct coloration from the rest of Pluto. Using a simple model haze particle as a colorant, we are not able to match the colors in both Lowell Regio and Cthulhu. To account for their distinct colors, we propose that after arrival at Pluto's surface, haze particles may be less inert than might be supposed from the low surface temperatures. They must either interact with local materials and environments to produce distinct products in different regions, or else the supply of haze must be non-uniform in time and/or location, such that different products are delivered to different places.
Published: 2019
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21. Radio thermal emission from Pluto and Charon during the New Horizons encounter

Author: Bird, M. K., Linscott, I. R., Tyler, G. L., Hinson, D. P., Paetzold, M., Summers, M. E., Strobel, D. F., Stern, S. A., Weaver, H. A., Olkin, C. B., Young, L. A., Ennico, K., Moore, J. M., Gladstone, G. R., Grundy, W. M., DeBoy, C. C., Vincent, M., Bird, M. K., Linscott, I. R., Tyler, G. L., Hinson, D. P., Paetzold, M., Summers, M. E., Strobel, D. F., Stern, S. A., Weaver, H. A., Olkin, C. B., Young, L. A., Ennico, K., Moore, J. M., Gladstone, G. R., Grundy, W. M., DeBoy, C. C., and Vincent, M.
Abstract: One component of the REX instrument on NASA's New Horizons spacecraft was an investigation of the radio continuum radiation from Pluto and Charon during the flyby on 14 July 2015. The planetary thermal emission was recorded at a wavelength of 4.17 cm (7.18 GHz) during approach, departure, and specifically on the non illuminated hemispheres of Pluto and Charon during the respective intervals between occultation ingress and egress. We derive the brightness temperatures for these disk-resolved and unresolved observations. The mean values and la deviations of brightness temperature for the unresolved sunlit disk are 33.2 +/- 1.4 K and 47.2 +/- 5.3 K for Pluto and Charon, respectively, consistent with the global albedos of the two bodies as well as with previous ground-based estimates at smaller wavelengths. A slightly colder temperature of 29.0 +/- 2.5 K was determined for the disk-integrated nightside of Pluto and a larger drop in temperature was observed for Charon (40.9 +/- 0.9 K), implying a smaller thermal inertia for Charon than Pluto. The measured brightness temperature of Pluto across the nightside diametric scan reached a maximum of 29.0 +/- 1.5 K in the center of the disk. The profile shape is attributed to an emissivity effect, which favors thermal emission toward higher elevation angles. As a first approximation, the effective emissivity for thermal emission is calculated for the case when Pluto and Charon are uniformly smooth homogenous spheres. Under this assumption, the effective emissivity for these observations is close to unity for all probable surface constituents, implying that the effective temperature of the Pluto subsurface is only a few percent higher than the observed brightness temperature. A considerably lower subsurface emissivity is implied, however, if the higher atmospheric temperatures near the surface determined from the REX occultation measurements are also valid for the subsurface.
Published: 2019

22. Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt object

Author: Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Careich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horanyi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kolmnann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., MeNutt, R. L., Jr., Mehoke, D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Nunez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Patzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendal, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffi, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. M., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Ii, G. E. Weigle, Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Wimters, H. L., Zangari, A. M., Zurbuchen, T. H., Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Careich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horanyi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kolmnann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., MeNutt, R. L., Jr., Mehoke, D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Nunez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Patzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendal, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffi, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. M., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Ii, G. E. Weigle, Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Wimters, H. L., Zangari, A. M., and Zurbuchen, T. H.
Abstract: The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.
Published: 2019

23. Radio thermal emission from Pluto and Charon during the New Horizons encounter

Author: Bird, M. K., Linscott, I. R., Tyler, G. L., Hinson, D. P., Paetzold, M., Summers, M. E., Strobel, D. F., Stern, S. A., Weaver, H. A., Olkin, C. B., Young, L. A., Ennico, K., Moore, J. M., Gladstone, G. R., Grundy, W. M., DeBoy, C. C., Vincent, M., Bird, M. K., Linscott, I. R., Tyler, G. L., Hinson, D. P., Paetzold, M., Summers, M. E., Strobel, D. F., Stern, S. A., Weaver, H. A., Olkin, C. B., Young, L. A., Ennico, K., Moore, J. M., Gladstone, G. R., Grundy, W. M., DeBoy, C. C., and Vincent, M.
Abstract: One component of the REX instrument on NASA's New Horizons spacecraft was an investigation of the radio continuum radiation from Pluto and Charon during the flyby on 14 July 2015. The planetary thermal emission was recorded at a wavelength of 4.17 cm (7.18 GHz) during approach, departure, and specifically on the non illuminated hemispheres of Pluto and Charon during the respective intervals between occultation ingress and egress. We derive the brightness temperatures for these disk-resolved and unresolved observations. The mean values and la deviations of brightness temperature for the unresolved sunlit disk are 33.2 +/- 1.4 K and 47.2 +/- 5.3 K for Pluto and Charon, respectively, consistent with the global albedos of the two bodies as well as with previous ground-based estimates at smaller wavelengths. A slightly colder temperature of 29.0 +/- 2.5 K was determined for the disk-integrated nightside of Pluto and a larger drop in temperature was observed for Charon (40.9 +/- 0.9 K), implying a smaller thermal inertia for Charon than Pluto. The measured brightness temperature of Pluto across the nightside diametric scan reached a maximum of 29.0 +/- 1.5 K in the center of the disk. The profile shape is attributed to an emissivity effect, which favors thermal emission toward higher elevation angles. As a first approximation, the effective emissivity for thermal emission is calculated for the case when Pluto and Charon are uniformly smooth homogenous spheres. Under this assumption, the effective emissivity for these observations is close to unity for all probable surface constituents, implying that the effective temperature of the Pluto subsurface is only a few percent higher than the observed brightness temperature. A considerably lower subsurface emissivity is implied, however, if the higher atmospheric temperatures near the surface determined from the REX occultation measurements are also valid for the subsurface.
Published: 2019

24. Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt object

Author: Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Careich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horanyi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kolmnann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., MeNutt, R. L., Jr., Mehoke, D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Nunez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Patzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendal, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffi, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. M., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Ii, G. E. Weigle, Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Wimters, H. L., Zangari, A. M., Zurbuchen, T. H., Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Careich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horanyi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kolmnann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., MeNutt, R. L., Jr., Mehoke, D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Nunez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Patzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendal, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffi, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. M., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Ii, G. E. Weigle, Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Wimters, H. L., Zangari, A. M., and Zurbuchen, T. H.
Abstract: The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.
Published: 2019

25. Pluto's Haze as a Surface Material

Author: Grundy, W. M., Bertrand, T., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A. F., Cook, J. C., Cruikshank, D. P., Devins, S. L., Ore, C. M. Dalle, Earle, A. M., Ennico, K., Forget, F., Gao, P., Gladstone1, G. R., Howett, C. J. A., Jennings, D. E., Kammer, J. A., Lauer, T. R., Linscott, I. R., Lisse, C. M., Lunsford, A. W., McKinnon, W. B., Olkin, C. B., Parker, A. H., Protopapa, S., Quirico, E., Reuter, D. C., Schmitt, B., Singer, K. N., Spencer, J. A., Stern, S. A., Strobel, D. F., Summers, M. E., Weaver, H. A., Weigle II, G. E., Wong, M. L., Young, E. F., Young, L. A., Zhang, X., Grundy, W. M., Bertrand, T., Binzel, R. P., Buie, M. W., Buratti, B. J., Cheng, A. F., Cook, J. C., Cruikshank, D. P., Devins, S. L., Ore, C. M. Dalle, Earle, A. M., Ennico, K., Forget, F., Gao, P., Gladstone1, G. R., Howett, C. J. A., Jennings, D. E., Kammer, J. A., Lauer, T. R., Linscott, I. R., Lisse, C. M., Lunsford, A. W., McKinnon, W. B., Olkin, C. B., Parker, A. H., Protopapa, S., Quirico, E., Reuter, D. C., Schmitt, B., Singer, K. N., Spencer, J. A., Stern, S. A., Strobel, D. F., Summers, M. E., Weaver, H. A., Weigle II, G. E., Wong, M. L., Young, E. F., Young, L. A., and Zhang, X.
Abstract: Pluto's atmospheric haze settles out rapidly compared with geological timescales. It needs to be accounted for as a surface material, distinct from Pluto's icy bedrock and from the volatile ices that migrate via sublimation and condensation on seasonal timescales. This paper explores how a steady supply of atmospheric haze might affect three distinct provinces on Pluto. We pose the question of why they each look so different from one another if the same haze material is settling out onto all of them. Cthulhu is a more ancient region with comparatively little present-day geological activity, where the haze appears to simply accumulate over time. Sputnik Planitia is a very active region where glacial convection, as well as sublimation and condensation rapidly refresh the surface, hiding recently deposited haze from view. Lowell Regio is a region of intermediate age featuring very distinct coloration from the rest of Pluto. Using a simple model haze particle as a colorant, we are not able to match the colors in both Lowell Regio and Cthulhu. To account for their distinct colors, we propose that after arrival at Pluto's surface, haze particles may be less inert than might be supposed from the low surface temperatures. They must either interact with local materials and environments to produce distinct products in different regions, or else the supply of haze must be non-uniform in time and/or location, such that different products are delivered to different places.
Published: 2019
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26. An upper limit on Pluto's ionosphere from radio occultation measurements with New Horizons

Author: Hinson, D. P., Linscott, I. R., Strobel, D. F., Tyler, G. L., Bird, M. K., Paetzold, M., Summers, M. E., Stern, S. A., Ennico, K., Gladstone, G. R., Olkin, C. B., Weaver, H. A., Woods, W. W., Young, L. A., Hinson, D. P., Linscott, I. R., Strobel, D. F., Tyler, G. L., Bird, M. K., Paetzold, M., Summers, M. E., Stern, S. A., Ennico, K., Gladstone, G. R., Olkin, C. B., Weaver, H. A., Woods, W. W., and Young, L. A.
Abstract: On 14 July 2015 New Horizons performed a radio occultation (RO) that sounded Pluto's neutral atmosphere and ionosphere. The solar zenith angle was 90.2 degrees (sunset) at entry and 89.8 degrees (sunrise) at exit. We examined the data for evidence of an ionosphere, using the same method of analysis as in a previous investigation of the neutral atmosphere (Hinson et al., 2017). No ionosphere was detected. The measurements are more accurate at occultation exit, where the 1-sigma sensitivity in integrated electron content (IEC) is 23 x 10(11) cm(-2). The corresponding upper bound on the peak electron density at the terminator is about 1000 cm(-3). We constructed a model for the ionosphere and used it to guide the analysis and interpretation of the RO data. Owing to the large abundance of CH4 at ionospheric heights, the dominant ions are molecular and the electron densities are relatively small. The model predicts a peak IEC of 1.8 x 10(11) cm(-2) for an occultation at the terminator, slightly smaller than the threshold of detection by New Horizons. (C) 2018 Elsevier Inc. All rights reserved.
Published: 2018

27. An upper limit on Pluto's ionosphere from radio occultation measurements with New Horizons

Author: Hinson, D. P., Linscott, I. R., Strobel, D. F., Tyler, G. L., Bird, M. K., Paetzold, M., Summers, M. E., Stern, S. A., Ennico, K., Gladstone, G. R., Olkin, C. B., Weaver, H. A., Woods, W. W., Young, L. A., Hinson, D. P., Linscott, I. R., Strobel, D. F., Tyler, G. L., Bird, M. K., Paetzold, M., Summers, M. E., Stern, S. A., Ennico, K., Gladstone, G. R., Olkin, C. B., Weaver, H. A., Woods, W. W., and Young, L. A.
Abstract: On 14 July 2015 New Horizons performed a radio occultation (RO) that sounded Pluto's neutral atmosphere and ionosphere. The solar zenith angle was 90.2 degrees (sunset) at entry and 89.8 degrees (sunrise) at exit. We examined the data for evidence of an ionosphere, using the same method of analysis as in a previous investigation of the neutral atmosphere (Hinson et al., 2017). No ionosphere was detected. The measurements are more accurate at occultation exit, where the 1-sigma sensitivity in integrated electron content (IEC) is 23 x 10(11) cm(-2). The corresponding upper bound on the peak electron density at the terminator is about 1000 cm(-3). We constructed a model for the ionosphere and used it to guide the analysis and interpretation of the RO data. Owing to the large abundance of CH4 at ionospheric heights, the dominant ions are molecular and the electron densities are relatively small. The model predicts a peak IEC of 1.8 x 10(11) cm(-2) for an occultation at the terminator, slightly smaller than the threshold of detection by New Horizons. (C) 2018 Elsevier Inc. All rights reserved.
Published: 2018

28. Radio occultation measurements of Pluto's neutral atmosphere with New Horizons

Author: Hinson, D. P., Linscott, I. R., Young, L. A., Tyler, G. L., Stern, S. A., Beyer, R. A., Bird, M. K., Ennico, K., Gladstone, G. R., Olkin, C. B., Paetzold, M., Schenk, P. M., Strobel, D. F., Summers, M. E., Weaver, H. A., Woods, W. W., Hinson, D. P., Linscott, I. R., Young, L. A., Tyler, G. L., Stern, S. A., Beyer, R. A., Bird, M. K., Ennico, K., Gladstone, G. R., Olkin, C. B., Paetzold, M., Schenk, P. M., Strobel, D. F., Summers, M. E., Weaver, H. A., and Woods, W. W.
Abstract: On 14 July 2015 New Horizons performed a radio occultation (RO) that sounded Pluto's atmosphere down to the surface. The sensitivity of the measurements was enhanced by a unique configuration of ground equipment and spacecraft instrumentation. Signals were transmitted simultaneously by four antennas of the NASA Deep Space Network, each radiating 20 kW at a wavelength of 4.2 cm. The polarization was right circular for one pair of signals and left circular for the other pair. New Horizons received the four signals and separated them by polarization for processing by two independent receivers, each referenced to a different ultra-stable oscillator. The two data streams were digitized, filtered, and stored on the spacecraft for later transmission to Earth. The results reported here are the first to utilize the complete set of observations. We calibrated each signal to remove effects not associated with Pluto's atmosphere, including the limb diffraction pattern. We then applied a specialized method of analysis to retrieve profiles of number density, pressure, and temperature from the combined phase measurements. Occultation entry sounded the atmosphere at sunset at 193.5 E, 17.0 S on the southeast margin of an ice-filled basin known informally as Sputnik Planitia (SP); occultation exit occurred at sunrise at 15.7 E, 15.1 degrees N - near the center of the Charon-facing hemisphere. Above 1215 km radius (similar to 25 km altitude) there is no discernible difference between the measurements at entry and exit, and the RO profiles are consistent with results derived from ground-based stellar occultation measurements. At lower altitudes the RO measurements reveal horizontal variations in atmospheric structure that had not been observed previously, and they are the first to reach the ground. The entry profile has a strong temperature inversion that ends 3.5 km above the surface, and the temperature in the cold boundary layer beneath the inversion is nearly constant, 38.9 +/- 2.
Published: 2017

29. Radio occultation measurements of Pluto's neutral atmosphere with New Horizons

Author: Hinson, D. P., Linscott, I. R., Young, L. A., Tyler, G. L., Stern, S. A., Beyer, R. A., Bird, M. K., Ennico, K., Gladstone, G. R., Olkin, C. B., Paetzold, M., Schenk, P. M., Strobel, D. F., Summers, M. E., Weaver, H. A., Woods, W. W., Hinson, D. P., Linscott, I. R., Young, L. A., Tyler, G. L., Stern, S. A., Beyer, R. A., Bird, M. K., Ennico, K., Gladstone, G. R., Olkin, C. B., Paetzold, M., Schenk, P. M., Strobel, D. F., Summers, M. E., Weaver, H. A., and Woods, W. W.
Abstract: On 14 July 2015 New Horizons performed a radio occultation (RO) that sounded Pluto's atmosphere down to the surface. The sensitivity of the measurements was enhanced by a unique configuration of ground equipment and spacecraft instrumentation. Signals were transmitted simultaneously by four antennas of the NASA Deep Space Network, each radiating 20 kW at a wavelength of 4.2 cm. The polarization was right circular for one pair of signals and left circular for the other pair. New Horizons received the four signals and separated them by polarization for processing by two independent receivers, each referenced to a different ultra-stable oscillator. The two data streams were digitized, filtered, and stored on the spacecraft for later transmission to Earth. The results reported here are the first to utilize the complete set of observations. We calibrated each signal to remove effects not associated with Pluto's atmosphere, including the limb diffraction pattern. We then applied a specialized method of analysis to retrieve profiles of number density, pressure, and temperature from the combined phase measurements. Occultation entry sounded the atmosphere at sunset at 193.5 E, 17.0 S on the southeast margin of an ice-filled basin known informally as Sputnik Planitia (SP); occultation exit occurred at sunrise at 15.7 E, 15.1 degrees N - near the center of the Charon-facing hemisphere. Above 1215 km radius (similar to 25 km altitude) there is no discernible difference between the measurements at entry and exit, and the RO profiles are consistent with results derived from ground-based stellar occultation measurements. At lower altitudes the RO measurements reveal horizontal variations in atmospheric structure that had not been observed previously, and they are the first to reach the ground. The entry profile has a strong temperature inversion that ends 3.5 km above the surface, and the temperature in the cold boundary layer beneath the inversion is nearly constant, 38.9 +/- 2.
Published: 2017

30. Inflight Radiometric Calibration of New Horizons' Multispectral Visible Imaging Camera (MVIC)

Author: Howett, C. J. A., Parker, A. H., Olkin, C. B., Reuter, D. C., Ennico, K., Grundy, W. M, Graps, A. L., Harrison, K. P., Throop, H. B., Buie, M. W., Lovering, J. R., Porter, S. B., Weaver, H. A., Young, L. A., Stern, S. A., Beyer, R. A., Binzell, R. P., Buratti, B. J., Cheng, A. F., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Jennings, D. E., Linscott, I. R., Lunsford, A. W., Parker, J. Wm., Phillippe, S., Protopapa, S., Quirico, E., Schenk, P. M., Schmitt, B., Singer, K. N., Spencer, J. R., Stansberry, J. A., Tsang, C. C. C., Weigle II, G. E., Verbiscer, A. J., Howett, C. J. A., Parker, A. H., Olkin, C. B., Reuter, D. C., Ennico, K., Grundy, W. M, Graps, A. L., Harrison, K. P., Throop, H. B., Buie, M. W., Lovering, J. R., Porter, S. B., Weaver, H. A., Young, L. A., Stern, S. A., Beyer, R. A., Binzell, R. P., Buratti, B. J., Cheng, A. F., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Jennings, D. E., Linscott, I. R., Lunsford, A. W., Parker, J. Wm., Phillippe, S., Protopapa, S., Quirico, E., Schenk, P. M., Schmitt, B., Singer, K. N., Spencer, J. R., Stansberry, J. A., Tsang, C. C. C., Weigle II, G. E., and Verbiscer, A. J.
Abstract: We discuss two semi-independent calibration techniques used to determine the in-flight radiometric calibration for the New Horizons' Multi-spectral Visible Imaging Camera (MVIC). The first calibration technique compares the observed stellar flux to modeled values. The difference between the two provides a calibration factor that allows the observed flux to be adjusted to the expected levels for all observations, for each detector. The second calibration technique is a channel-wise relative radiometric calibration for MVIC's blue, near-infrared and methane color channels using observations of Charon and scaling from the red channel stellar calibration. Both calibration techniques produce very similar results (better than 7% agreement), providing strong validation for the techniques used. Since the stellar calibration can be performed without a color target in the field of view and covers all of MVIC's detectors, this calibration was used to provide the radiometric keywords delivered by the New Horizons project to the Planetary Data System (PDS). These keywords allow each observation to be converted from counts to physical units; a description of how these keywords were generated is included. Finally, mitigation techniques adopted for the gain drift observed in the near-infrared detector and one of the panchromatic framing cameras is also discussed.
Published: 2016
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31. Surface Compositions Across Pluto and Charon

Author: Grundy, W. M., Binzel, R. P., Buratti, B. J., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Ennico, K., Howett, C. J. A., Lunsford, A. W., Olkin, C. B., Parker, A. H., Philippe, S., Protopapa, S., Quirico, E., Reuter, D. C., Schmitt, B., Singer, K. N., Verbiscer, A. J., Beyer, R. A., Buie, M. W., Cheng, A. F., Jennings, D. E., Linscott, I. R., Parker, J. Wm., Schenk, P. M., Spencer, J. R., Stansberry, J. A., Stern, S. A., Throop, H. B., Tsang, C. C. C., Weaver, H. A., Weigle II, G. E., Young, L. A., Team, the New Horizons Science, Grundy, W. M., Binzel, R. P., Buratti, B. J., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Ennico, K., Howett, C. J. A., Lunsford, A. W., Olkin, C. B., Parker, A. H., Philippe, S., Protopapa, S., Quirico, E., Reuter, D. C., Schmitt, B., Singer, K. N., Verbiscer, A. J., Beyer, R. A., Buie, M. W., Cheng, A. F., Jennings, D. E., Linscott, I. R., Parker, J. Wm., Schenk, P. M., Spencer, J. R., Stansberry, J. A., Stern, S. A., Throop, H. B., Tsang, C. C. C., Weaver, H. A., Weigle II, G. E., Young, L. A., and Team, the New Horizons Science
Abstract: The New Horizons spacecraft mapped colors and infrared spectra across the encounter hemispheres of Pluto and Charon. The volatile ices CH$_4$, CO, and N$_2$, that dominate Pluto's surface, have complicated spatial distributions resulting from sublimation, condensation, and glacial flow acting over seasonal and geological timescales. Pluto's H$_2$O ice "bedrock" is also mapped, with isolated outcrops occurring in a variety of settings. Pluto's surface exhibits complex regional color diversity associated with its distinct provinces. Charon's color pattern is simpler, dominated by neutral low latitudes and a reddish northern polar region. Charon near infrared spectra reveal highly localized areas with strong NH$_3$ absorption tied to small craters with relatively fresh-appearing impact ejecta., Comment: in Science 351, aad9189 (2016)
Published: 2016
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32. The Small Satellites of Pluto as Observed by New Horizons

Author: Weaver, H. A., Buie, M. W., Buratti, B. J., Grundy, W. M., Lauer, T. R., Olkin, C. B., Parker, A. H., Porter, S. B., Showalter, M. R., Spencer, J. R., Stern, S. A., Verbiscer, A. J., McKinnon, W. B., Moore, J. M., Robbins, S. J., Schenk, P., Singer, K. N., Barnouin, O. S., Cheng, A. F., Ernst, C. M., Lisse, C. M., Jennings, D. E., Lunsford, A. W., Reuter, D. C., Hamilton, D. P., Kaufmann, D. E., Ennico, K., Young, L. A., Beyer, R. A., Binzel, R. P., Bray, V. J., Chaikin, A. L., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Gladstone, G. R., Howett, C. J. A., Linscott, I. R., Nimmo, F., Parker, J. Wm., Philippe, S., Protopapa, S., Reitsema, H. J., Schmitt, B., Stryk, T., Summers, M. E., Tsang, C. C. C., Throop, H. H. B., White, O. L., Zangari, A. M., Weaver, H. A., Buie, M. W., Buratti, B. J., Grundy, W. M., Lauer, T. R., Olkin, C. B., Parker, A. H., Porter, S. B., Showalter, M. R., Spencer, J. R., Stern, S. A., Verbiscer, A. J., McKinnon, W. B., Moore, J. M., Robbins, S. J., Schenk, P., Singer, K. N., Barnouin, O. S., Cheng, A. F., Ernst, C. M., Lisse, C. M., Jennings, D. E., Lunsford, A. W., Reuter, D. C., Hamilton, D. P., Kaufmann, D. E., Ennico, K., Young, L. A., Beyer, R. A., Binzel, R. P., Bray, V. J., Chaikin, A. L., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Gladstone, G. R., Howett, C. J. A., Linscott, I. R., Nimmo, F., Parker, J. Wm., Philippe, S., Protopapa, S., Reitsema, H. J., Schmitt, B., Stryk, T., Summers, M. E., Tsang, C. C. C., Throop, H. H. B., White, O. L., and Zangari, A. M.
Abstract: The New Horizons mission has provided resolved measurements of Pluto's moons Styx, Nix, Kerberos, and Hydra. All four are small, with equivalent spherical diameters of $\approx$40 km for Nix and Hydra and ~10 km for Styx and Kerberos. They are also highly elongated, with maximum to minimum axis ratios of $\approx$2. All four moons have high albedos ( $\approx$50-90 %) suggestive of a water-ice surface composition. Crater densities on Nix and Hydra imply surface ages $\gtrsim$ 4 Ga. The small moons rotate much faster than synchronous, with rotational poles clustered nearly orthogonal to the common pole directions of Pluto and Charon. These results reinforce the hypothesis that the small moons formed in the aftermath of a collision that produced the Pluto-Charon binary., Comment: in Science 351, aae0030 (2016)
Published: 2016
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33. Surface Compositions Across Pluto and Charon

Author: Grundy, W. M., Binzel, R. P., Buratti, B. J., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Ennico, K., Howett, C. J. A., Lunsford, A. W., Olkin, C. B., Parker, A. H., Philippe, S., Protopapa, S., Quirico, E., Reuter, D. C., Schmitt, B., Singer, K. N., Verbiscer, A. J., Beyer, R. A., Buie, M. W., Cheng, A. F., Jennings, D. E., Linscott, I. R., Parker, J. Wm., Schenk, P. M., Spencer, J. R., Stansberry, J. A., Stern, S. A., Throop, H. B., Tsang, C. C. C., Weaver, H. A., Weigle II, G. E., Young, L. A., Team, the New Horizons Science, Grundy, W. M., Binzel, R. P., Buratti, B. J., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Ennico, K., Howett, C. J. A., Lunsford, A. W., Olkin, C. B., Parker, A. H., Philippe, S., Protopapa, S., Quirico, E., Reuter, D. C., Schmitt, B., Singer, K. N., Verbiscer, A. J., Beyer, R. A., Buie, M. W., Cheng, A. F., Jennings, D. E., Linscott, I. R., Parker, J. Wm., Schenk, P. M., Spencer, J. R., Stansberry, J. A., Stern, S. A., Throop, H. B., Tsang, C. C. C., Weaver, H. A., Weigle II, G. E., Young, L. A., and Team, the New Horizons Science
Abstract: The New Horizons spacecraft mapped colors and infrared spectra across the encounter hemispheres of Pluto and Charon. The volatile ices CH$_4$, CO, and N$_2$, that dominate Pluto's surface, have complicated spatial distributions resulting from sublimation, condensation, and glacial flow acting over seasonal and geological timescales. Pluto's H$_2$O ice "bedrock" is also mapped, with isolated outcrops occurring in a variety of settings. Pluto's surface exhibits complex regional color diversity associated with its distinct provinces. Charon's color pattern is simpler, dominated by neutral low latitudes and a reddish northern polar region. Charon near infrared spectra reveal highly localized areas with strong NH$_3$ absorption tied to small craters with relatively fresh-appearing impact ejecta., Comment: in Science 351, aad9189 (2016)
Published: 2016
Full Text: View/download PDF

34. The Small Satellites of Pluto as Observed by New Horizons

Author: Weaver, H. A., Buie, M. W., Buratti, B. J., Grundy, W. M., Lauer, T. R., Olkin, C. B., Parker, A. H., Porter, S. B., Showalter, M. R., Spencer, J. R., Stern, S. A., Verbiscer, A. J., McKinnon, W. B., Moore, J. M., Robbins, S. J., Schenk, P., Singer, K. N., Barnouin, O. S., Cheng, A. F., Ernst, C. M., Lisse, C. M., Jennings, D. E., Lunsford, A. W., Reuter, D. C., Hamilton, D. P., Kaufmann, D. E., Ennico, K., Young, L. A., Beyer, R. A., Binzel, R. P., Bray, V. J., Chaikin, A. L., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Gladstone, G. R., Howett, C. J. A., Linscott, I. R., Nimmo, F., Parker, J. Wm., Philippe, S., Protopapa, S., Reitsema, H. J., Schmitt, B., Stryk, T., Summers, M. E., Tsang, C. C. C., Throop, H. H. B., White, O. L., Zangari, A. M., Weaver, H. A., Buie, M. W., Buratti, B. J., Grundy, W. M., Lauer, T. R., Olkin, C. B., Parker, A. H., Porter, S. B., Showalter, M. R., Spencer, J. R., Stern, S. A., Verbiscer, A. J., McKinnon, W. B., Moore, J. M., Robbins, S. J., Schenk, P., Singer, K. N., Barnouin, O. S., Cheng, A. F., Ernst, C. M., Lisse, C. M., Jennings, D. E., Lunsford, A. W., Reuter, D. C., Hamilton, D. P., Kaufmann, D. E., Ennico, K., Young, L. A., Beyer, R. A., Binzel, R. P., Bray, V. J., Chaikin, A. L., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Gladstone, G. R., Howett, C. J. A., Linscott, I. R., Nimmo, F., Parker, J. Wm., Philippe, S., Protopapa, S., Reitsema, H. J., Schmitt, B., Stryk, T., Summers, M. E., Tsang, C. C. C., Throop, H. H. B., White, O. L., and Zangari, A. M.
Abstract: The New Horizons mission has provided resolved measurements of Pluto's moons Styx, Nix, Kerberos, and Hydra. All four are small, with equivalent spherical diameters of $\approx$40 km for Nix and Hydra and ~10 km for Styx and Kerberos. They are also highly elongated, with maximum to minimum axis ratios of $\approx$2. All four moons have high albedos ( $\approx$50-90 %) suggestive of a water-ice surface composition. Crater densities on Nix and Hydra imply surface ages $\gtrsim$ 4 Ga. The small moons rotate much faster than synchronous, with rotational poles clustered nearly orthogonal to the common pole directions of Pluto and Charon. These results reinforce the hypothesis that the small moons formed in the aftermath of a collision that produced the Pluto-Charon binary., Comment: in Science 351, aae0030 (2016)
Published: 2016
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35. Inflight Radiometric Calibration of New Horizons' Multispectral Visible Imaging Camera (MVIC)

Author: Howett, C. J. A., Parker, A. H., Olkin, C. B., Reuter, D. C., Ennico, K., Grundy, W. M, Graps, A. L., Harrison, K. P., Throop, H. B., Buie, M. W., Lovering, J. R., Porter, S. B., Weaver, H. A., Young, L. A., Stern, S. A., Beyer, R. A., Binzell, R. P., Buratti, B. J., Cheng, A. F., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Jennings, D. E., Linscott, I. R., Lunsford, A. W., Parker, J. Wm., Phillippe, S., Protopapa, S., Quirico, E., Schenk, P. M., Schmitt, B., Singer, K. N., Spencer, J. R., Stansberry, J. A., Tsang, C. C. C., Weigle II, G. E., Verbiscer, A. J., Howett, C. J. A., Parker, A. H., Olkin, C. B., Reuter, D. C., Ennico, K., Grundy, W. M, Graps, A. L., Harrison, K. P., Throop, H. B., Buie, M. W., Lovering, J. R., Porter, S. B., Weaver, H. A., Young, L. A., Stern, S. A., Beyer, R. A., Binzell, R. P., Buratti, B. J., Cheng, A. F., Cook, J. C., Cruikshank, D. P., Ore, C. M. Dalle, Earle, A. M., Jennings, D. E., Linscott, I. R., Lunsford, A. W., Parker, J. Wm., Phillippe, S., Protopapa, S., Quirico, E., Schenk, P. M., Schmitt, B., Singer, K. N., Spencer, J. R., Stansberry, J. A., Tsang, C. C. C., Weigle II, G. E., and Verbiscer, A. J.
Abstract: We discuss two semi-independent calibration techniques used to determine the in-flight radiometric calibration for the New Horizons' Multi-spectral Visible Imaging Camera (MVIC). The first calibration technique compares the observed stellar flux to modeled values. The difference between the two provides a calibration factor that allows the observed flux to be adjusted to the expected levels for all observations, for each detector. The second calibration technique is a channel-wise relative radiometric calibration for MVIC's blue, near-infrared and methane color channels using observations of Charon and scaling from the red channel stellar calibration. Both calibration techniques produce very similar results (better than 7% agreement), providing strong validation for the techniques used. Since the stellar calibration can be performed without a color target in the field of view and covers all of MVIC's detectors, this calibration was used to provide the radiometric keywords delivered by the New Horizons project to the Planetary Data System (PDS). These keywords allow each observation to be converted from counts to physical units; a description of how these keywords were generated is included. Finally, mitigation techniques adopted for the gain drift observed in the near-infrared detector and one of the panchromatic framing cameras is also discussed.
Published: 2016
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36. The Pluto system: Initial results from its exploration by New Horizons

Author: Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., Moore, J. M., Olkin, C. B., Spencer, J. R., Weaver, H. A., Young, L. A., Andert, T., Andrews, J., Banks, M., Bauer, B., Bauman, J., Barnouin, O. S., Bedini, P., Beisser, K., Beyer, R. A., Bhaskaran, S., Binzel, R. P., Birath, E., Bird, M., Bogan, D. J., Bowman, A., Bray, V. J., Brozovic, M., Bryan, C., Buckley, M. R., Buie, M. W., Buratti, B. J., Bushman, S. S., Calloway, A., Carcich, B., Cheng, A. F., Conard, S., Conrad, C. A., Cook, J. C., Cruikshank, D. P., Custodio, O. S., Ore, C. M. Dalle, Deboy, C., Dischner, Z. J. B., Dumont, P., Earle, A. M., Elliott, H. A., Ercol, J., Ernst, C. M., Finley, T., Flanigan, S. H., Fountain, G., Freeze, M. J., Greathouse, T., Green, J. L., Guo, Y., Hahn, M., Hamilton, D. P., Hamilton, S. A., Hanley, J., Harch, A., Hart, H. M., Hersman, C. B., Hill, A., Hill, M. E., Hinson, D. P., Holdridge, M. E., Horanyi, M., Howard, A. D., Howett, C. J. A., Jackman, C., Jacobson, R. A., Jennings, D. E., Kammer, J. A., Kang, H. K., Kaufmann, D. E., Kollmann, P., Krimigis, S. M., Kusnierkiewicz, D., Lauer, T. R., Lee, J. E., Lindstrom, K. L., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mallder, V. A., Martin, N., McComas, D. J., McNutt Jr., R. L., Mehoke, D., Mehoke, T., Melin, E. D., Mutchler, M., Nelson, D., Nimmo, F., Nunez, J. I., Ocampo, A., Owen, W. M., Paetzold, M., Page, B., Parker, A. H., Parker, J. W., Pelletier, F., Peterson, J., Pinkine, N., Piquette, M., Porter, S. B., Protopapa, S., Redfern, J., Reitsema, H. J., Reuter, D. C., Roberts, J. H., Robbins, S. J., Rogers, G., Rose, D., Runyon, K., Retherford, K. D., Ryschkewitsch, M. G., Schenk, P., Schindhelm, R., Sepan, B., Showalter, M. R., Singer, K. N., Soluri, M., Stanbridge, D., Steffl, A. J., Strobel, D. F., Stryk, T., Summers, M. E., Szalay, J. R., Tapley, M., Taylor, A., Taylor, H., Throop, H. B., Tsang, C. C. C., Tyler, G. L., Umurhan, O. M., Verbiscer, A. J., Versteeg, M. H., Vincent, M., Webbert, R., Weidner, S., Weigle II, G. E., White, O. L., Whittenburg, K., Williams, B. G., Williams, K., Williams, S., Woods, W. W., Zangari, A. M., Zirnstein, E., Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., Moore, J. M., Olkin, C. B., Spencer, J. R., Weaver, H. A., Young, L. A., Andert, T., Andrews, J., Banks, M., Bauer, B., Bauman, J., Barnouin, O. S., Bedini, P., Beisser, K., Beyer, R. A., Bhaskaran, S., Binzel, R. P., Birath, E., Bird, M., Bogan, D. J., Bowman, A., Bray, V. J., Brozovic, M., Bryan, C., Buckley, M. R., Buie, M. W., Buratti, B. J., Bushman, S. S., Calloway, A., Carcich, B., Cheng, A. F., Conard, S., Conrad, C. A., Cook, J. C., Cruikshank, D. P., Custodio, O. S., Ore, C. M. Dalle, Deboy, C., Dischner, Z. J. B., Dumont, P., Earle, A. M., Elliott, H. A., Ercol, J., Ernst, C. M., Finley, T., Flanigan, S. H., Fountain, G., Freeze, M. J., Greathouse, T., Green, J. L., Guo, Y., Hahn, M., Hamilton, D. P., Hamilton, S. A., Hanley, J., Harch, A., Hart, H. M., Hersman, C. B., Hill, A., Hill, M. E., Hinson, D. P., Holdridge, M. E., Horanyi, M., Howard, A. D., Howett, C. J. A., Jackman, C., Jacobson, R. A., Jennings, D. E., Kammer, J. A., Kang, H. K., Kaufmann, D. E., Kollmann, P., Krimigis, S. M., Kusnierkiewicz, D., Lauer, T. R., Lee, J. E., Lindstrom, K. L., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mallder, V. A., Martin, N., McComas, D. J., McNutt Jr., R. L., Mehoke, D., Mehoke, T., Melin, E. D., Mutchler, M., Nelson, D., Nimmo, F., Nunez, J. I., Ocampo, A., Owen, W. M., Paetzold, M., Page, B., Parker, A. H., Parker, J. W., Pelletier, F., Peterson, J., Pinkine, N., Piquette, M., Porter, S. B., Protopapa, S., Redfern, J., Reitsema, H. J., Reuter, D. C., Roberts, J. H., Robbins, S. J., Rogers, G., Rose, D., Runyon, K., Retherford, K. D., Ryschkewitsch, M. G., Schenk, P., Schindhelm, R., Sepan, B., Showalter, M. R., Singer, K. N., Soluri, M., Stanbridge, D., Steffl, A. J., Strobel, D. F., Stryk, T., Summers, M. E., Szalay, J. R., Tapley, M., Taylor, A., Taylor, H., Throop, H. B., Tsang, C. C. C., Tyler, G. L., Umurhan, O. M., Verbiscer, A. J., Versteeg, M. H., Vincent, M., Webbert, R., Weidner, S., Weigle II, G. E., White, O. L., Whittenburg, K., Williams, B. G., Williams, K., Williams, S., Woods, W. W., Zangari, A. M., and Zirnstein, E.
Abstract: The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition, its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected., Comment: 8 pages - Initial Science paper from NASA's New Horizons Pluto Encounter
Published: 2015
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37. The Pluto system: Initial results from its exploration by New Horizons

Author: Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., Moore, J. M., Olkin, C. B., Spencer, J. R., Weaver, H. A., Young, L. A., Andert, T., Andrews, J., Banks, M., Bauer, B., Bauman, J., Barnouin, O. S., Bedini, P., Beisser, K., Beyer, R. A., Bhaskaran, S., Binzel, R. P., Birath, E., Bird, M., Bogan, D. J., Bowman, A., Bray, V. J., Brozovic, M., Bryan, C., Buckley, M. R., Buie, M. W., Buratti, B. J., Bushman, S. S., Calloway, A., Carcich, B., Cheng, A. F., Conard, S., Conrad, C. A., Cook, J. C., Cruikshank, D. P., Custodio, O. S., Ore, C. M. Dalle, Deboy, C., Dischner, Z. J. B., Dumont, P., Earle, A. M., Elliott, H. A., Ercol, J., Ernst, C. M., Finley, T., Flanigan, S. H., Fountain, G., Freeze, M. J., Greathouse, T., Green, J. L., Guo, Y., Hahn, M., Hamilton, D. P., Hamilton, S. A., Hanley, J., Harch, A., Hart, H. M., Hersman, C. B., Hill, A., Hill, M. E., Hinson, D. P., Holdridge, M. E., Horanyi, M., Howard, A. D., Howett, C. J. A., Jackman, C., Jacobson, R. A., Jennings, D. E., Kammer, J. A., Kang, H. K., Kaufmann, D. E., Kollmann, P., Krimigis, S. M., Kusnierkiewicz, D., Lauer, T. R., Lee, J. E., Lindstrom, K. L., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mallder, V. A., Martin, N., McComas, D. J., McNutt, R. L., Jr., Mehoke, D., Mehoke, T., Melin, E. D., Mutchler, M., Nelson, D., Nimmo, F., Nunez, J. I., Ocampo, A., Owen, W. M., Paetzold, M., Page, B., Parker, A. H., Parker, J. W., Pelletier, F., Peterson, J., Pinkine, N., Piquette, M., Porter, S. B., Protopapa, S., Redfern, J., Reitsema, H. J., Reuter, D. C., Roberts, J. H., Robbins, S. J., Rogers, G., Rose, D., Runyon, K., Retherford, K. D., Ryschkewitsch, M. G., Schenk, P., Schindhelm, E., Sepan, B., Showalter, M. K., Singer, K. N., Soluri, M., Stanbridge, D., Steffl, A. J., Strobel, D. F., Stryk, T., Summers, M. E., Szalay, J. R., Tapley, M., Taylor, A., Taylor, H., Throop, H. B., Tsang, C. C. C., Tyler, G. L., Umurhan, O. M., Verbiscer, A. J., Versteeg, M. H., Vincent, M., Webber, R., Weidner, S., Weigle, G. E., II, White, O. L., Whittenburg, K., Williams, B. G., Williams, K., Williams, S., Woods, W. W., Zangari, A. M., Zirnstein, E., Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., Moore, J. M., Olkin, C. B., Spencer, J. R., Weaver, H. A., Young, L. A., Andert, T., Andrews, J., Banks, M., Bauer, B., Bauman, J., Barnouin, O. S., Bedini, P., Beisser, K., Beyer, R. A., Bhaskaran, S., Binzel, R. P., Birath, E., Bird, M., Bogan, D. J., Bowman, A., Bray, V. J., Brozovic, M., Bryan, C., Buckley, M. R., Buie, M. W., Buratti, B. J., Bushman, S. S., Calloway, A., Carcich, B., Cheng, A. F., Conard, S., Conrad, C. A., Cook, J. C., Cruikshank, D. P., Custodio, O. S., Ore, C. M. Dalle, Deboy, C., Dischner, Z. J. B., Dumont, P., Earle, A. M., Elliott, H. A., Ercol, J., Ernst, C. M., Finley, T., Flanigan, S. H., Fountain, G., Freeze, M. J., Greathouse, T., Green, J. L., Guo, Y., Hahn, M., Hamilton, D. P., Hamilton, S. A., Hanley, J., Harch, A., Hart, H. M., Hersman, C. B., Hill, A., Hill, M. E., Hinson, D. P., Holdridge, M. E., Horanyi, M., Howard, A. D., Howett, C. J. A., Jackman, C., Jacobson, R. A., Jennings, D. E., Kammer, J. A., Kang, H. K., Kaufmann, D. E., Kollmann, P., Krimigis, S. M., Kusnierkiewicz, D., Lauer, T. R., Lee, J. E., Lindstrom, K. L., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mallder, V. A., Martin, N., McComas, D. J., McNutt, R. L., Jr., Mehoke, D., Mehoke, T., Melin, E. D., Mutchler, M., Nelson, D., Nimmo, F., Nunez, J. I., Ocampo, A., Owen, W. M., Paetzold, M., Page, B., Parker, A. H., Parker, J. W., Pelletier, F., Peterson, J., Pinkine, N., Piquette, M., Porter, S. B., Protopapa, S., Redfern, J., Reitsema, H. J., Reuter, D. C., Roberts, J. H., Robbins, S. J., Rogers, G., Rose, D., Runyon, K., Retherford, K. D., Ryschkewitsch, M. G., Schenk, P., Schindhelm, E., Sepan, B., Showalter, M. K., Singer, K. N., Soluri, M., Stanbridge, D., Steffl, A. J., Strobel, D. F., Stryk, T., Summers, M. E., Szalay, J. R., Tapley, M., Taylor, A., Taylor, H., Throop, H. B., Tsang, C. C. C., Tyler, G. L., Umurhan, O. M., Verbiscer, A. J., Versteeg, M. H., Vincent, M., Webber, R., Weidner, S., Weigle, G. E., II, White, O. L., Whittenburg, K., Williams, B. G., Williams, K., Williams, S., Woods, W. W., Zangari, A. M., and Zirnstein, E.
Abstract: The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected.
Published: 2015

38. The Pluto system: Initial results from its exploration by New Horizons

Author: Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., Moore, J. M., Olkin, C. B., Spencer, J. R., Weaver, H. A., Young, L. A., Andert, T., Andrews, J., Banks, M., Bauer, B., Bauman, J., Barnouin, O. S., Bedini, P., Beisser, K., Beyer, R. A., Bhaskaran, S., Binzel, R. P., Birath, E., Bird, M., Bogan, D. J., Bowman, A., Bray, V. J., Brozovic, M., Bryan, C., Buckley, M. R., Buie, M. W., Buratti, B. J., Bushman, S. S., Calloway, A., Carcich, B., Cheng, A. F., Conard, S., Conrad, C. A., Cook, J. C., Cruikshank, D. P., Custodio, O. S., Ore, C. M. Dalle, Deboy, C., Dischner, Z. J. B., Dumont, P., Earle, A. M., Elliott, H. A., Ercol, J., Ernst, C. M., Finley, T., Flanigan, S. H., Fountain, G., Freeze, M. J., Greathouse, T., Green, J. L., Guo, Y., Hahn, M., Hamilton, D. P., Hamilton, S. A., Hanley, J., Harch, A., Hart, H. M., Hersman, C. B., Hill, A., Hill, M. E., Hinson, D. P., Holdridge, M. E., Horanyi, M., Howard, A. D., Howett, C. J. A., Jackman, C., Jacobson, R. A., Jennings, D. E., Kammer, J. A., Kang, H. K., Kaufmann, D. E., Kollmann, P., Krimigis, S. M., Kusnierkiewicz, D., Lauer, T. R., Lee, J. E., Lindstrom, K. L., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mallder, V. A., Martin, N., McComas, D. J., McNutt, R. L., Jr., Mehoke, D., Mehoke, T., Melin, E. D., Mutchler, M., Nelson, D., Nimmo, F., Nunez, J. I., Ocampo, A., Owen, W. M., Paetzold, M., Page, B., Parker, A. H., Parker, J. W., Pelletier, F., Peterson, J., Pinkine, N., Piquette, M., Porter, S. B., Protopapa, S., Redfern, J., Reitsema, H. J., Reuter, D. C., Roberts, J. H., Robbins, S. J., Rogers, G., Rose, D., Runyon, K., Retherford, K. D., Ryschkewitsch, M. G., Schenk, P., Schindhelm, E., Sepan, B., Showalter, M. K., Singer, K. N., Soluri, M., Stanbridge, D., Steffl, A. J., Strobel, D. F., Stryk, T., Summers, M. E., Szalay, J. R., Tapley, M., Taylor, A., Taylor, H., Throop, H. B., Tsang, C. C. C., Tyler, G. L., Umurhan, O. M., Verbiscer, A. J., Versteeg, M. H., Vincent, M., Webber, R., Weidner, S., Weigle, G. E., II, White, O. L., Whittenburg, K., Williams, B. G., Williams, K., Williams, S., Woods, W. W., Zangari, A. M., Zirnstein, E., Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., Moore, J. M., Olkin, C. B., Spencer, J. R., Weaver, H. A., Young, L. A., Andert, T., Andrews, J., Banks, M., Bauer, B., Bauman, J., Barnouin, O. S., Bedini, P., Beisser, K., Beyer, R. A., Bhaskaran, S., Binzel, R. P., Birath, E., Bird, M., Bogan, D. J., Bowman, A., Bray, V. J., Brozovic, M., Bryan, C., Buckley, M. R., Buie, M. W., Buratti, B. J., Bushman, S. S., Calloway, A., Carcich, B., Cheng, A. F., Conard, S., Conrad, C. A., Cook, J. C., Cruikshank, D. P., Custodio, O. S., Ore, C. M. Dalle, Deboy, C., Dischner, Z. J. B., Dumont, P., Earle, A. M., Elliott, H. A., Ercol, J., Ernst, C. M., Finley, T., Flanigan, S. H., Fountain, G., Freeze, M. J., Greathouse, T., Green, J. L., Guo, Y., Hahn, M., Hamilton, D. P., Hamilton, S. A., Hanley, J., Harch, A., Hart, H. M., Hersman, C. B., Hill, A., Hill, M. E., Hinson, D. P., Holdridge, M. E., Horanyi, M., Howard, A. D., Howett, C. J. A., Jackman, C., Jacobson, R. A., Jennings, D. E., Kammer, J. A., Kang, H. K., Kaufmann, D. E., Kollmann, P., Krimigis, S. M., Kusnierkiewicz, D., Lauer, T. R., Lee, J. E., Lindstrom, K. L., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mallder, V. A., Martin, N., McComas, D. J., McNutt, R. L., Jr., Mehoke, D., Mehoke, T., Melin, E. D., Mutchler, M., Nelson, D., Nimmo, F., Nunez, J. I., Ocampo, A., Owen, W. M., Paetzold, M., Page, B., Parker, A. H., Parker, J. W., Pelletier, F., Peterson, J., Pinkine, N., Piquette, M., Porter, S. B., Protopapa, S., Redfern, J., Reitsema, H. J., Reuter, D. C., Roberts, J. H., Robbins, S. J., Rogers, G., Rose, D., Runyon, K., Retherford, K. D., Ryschkewitsch, M. G., Schenk, P., Schindhelm, E., Sepan, B., Showalter, M. K., Singer, K. N., Soluri, M., Stanbridge, D., Steffl, A. J., Strobel, D. F., Stryk, T., Summers, M. E., Szalay, J. R., Tapley, M., Taylor, A., Taylor, H., Throop, H. B., Tsang, C. C. C., Tyler, G. L., Umurhan, O. M., Verbiscer, A. J., Versteeg, M. H., Vincent, M., Webber, R., Weidner, S., Weigle, G. E., II, White, O. L., Whittenburg, K., Williams, B. G., Williams, K., Williams, S., Woods, W. W., Zangari, A. M., and Zirnstein, E.
Abstract: The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected.
Published: 2015

39. The Pluto system: Initial results from its exploration by New Horizons

Author: Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., Moore, J. M., Olkin, C. B., Spencer, J. R., Weaver, H. A., Young, L. A., Andert, T., Andrews, J., Banks, M., Bauer, B., Bauman, J., Barnouin, O. S., Bedini, P., Beisser, K., Beyer, R. A., Bhaskaran, S., Binzel, R. P., Birath, E., Bird, M., Bogan, D. J., Bowman, A., Bray, V. J., Brozovic, M., Bryan, C., Buckley, M. R., Buie, M. W., Buratti, B. J., Bushman, S. S., Calloway, A., Carcich, B., Cheng, A. F., Conard, S., Conrad, C. A., Cook, J. C., Cruikshank, D. P., Custodio, O. S., Ore, C. M. Dalle, Deboy, C., Dischner, Z. J. B., Dumont, P., Earle, A. M., Elliott, H. A., Ercol, J., Ernst, C. M., Finley, T., Flanigan, S. H., Fountain, G., Freeze, M. J., Greathouse, T., Green, J. L., Guo, Y., Hahn, M., Hamilton, D. P., Hamilton, S. A., Hanley, J., Harch, A., Hart, H. M., Hersman, C. B., Hill, A., Hill, M. E., Hinson, D. P., Holdridge, M. E., Horanyi, M., Howard, A. D., Howett, C. J. A., Jackman, C., Jacobson, R. A., Jennings, D. E., Kammer, J. A., Kang, H. K., Kaufmann, D. E., Kollmann, P., Krimigis, S. M., Kusnierkiewicz, D., Lauer, T. R., Lee, J. E., Lindstrom, K. L., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mallder, V. A., Martin, N., McComas, D. J., McNutt Jr., R. L., Mehoke, D., Mehoke, T., Melin, E. D., Mutchler, M., Nelson, D., Nimmo, F., Nunez, J. I., Ocampo, A., Owen, W. M., Paetzold, M., Page, B., Parker, A. H., Parker, J. W., Pelletier, F., Peterson, J., Pinkine, N., Piquette, M., Porter, S. B., Protopapa, S., Redfern, J., Reitsema, H. J., Reuter, D. C., Roberts, J. H., Robbins, S. J., Rogers, G., Rose, D., Runyon, K., Retherford, K. D., Ryschkewitsch, M. G., Schenk, P., Schindhelm, R., Sepan, B., Showalter, M. R., Singer, K. N., Soluri, M., Stanbridge, D., Steffl, A. J., Strobel, D. F., Stryk, T., Summers, M. E., Szalay, J. R., Tapley, M., Taylor, A., Taylor, H., Throop, H. B., Tsang, C. C. C., Tyler, G. L., Umurhan, O. M., Verbiscer, A. J., Versteeg, M. H., Vincent, M., Webbert, R., Weidner, S., Weigle II, G. E., White, O. L., Whittenburg, K., Williams, B. G., Williams, K., Williams, S., Woods, W. W., Zangari, A. M., Zirnstein, E., Stern, S. A., Bagenal, F., Ennico, K., Gladstone, G. R., Grundy, W. M., McKinnon, W. B., Moore, J. M., Olkin, C. B., Spencer, J. R., Weaver, H. A., Young, L. A., Andert, T., Andrews, J., Banks, M., Bauer, B., Bauman, J., Barnouin, O. S., Bedini, P., Beisser, K., Beyer, R. A., Bhaskaran, S., Binzel, R. P., Birath, E., Bird, M., Bogan, D. J., Bowman, A., Bray, V. J., Brozovic, M., Bryan, C., Buckley, M. R., Buie, M. W., Buratti, B. J., Bushman, S. S., Calloway, A., Carcich, B., Cheng, A. F., Conard, S., Conrad, C. A., Cook, J. C., Cruikshank, D. P., Custodio, O. S., Ore, C. M. Dalle, Deboy, C., Dischner, Z. J. B., Dumont, P., Earle, A. M., Elliott, H. A., Ercol, J., Ernst, C. M., Finley, T., Flanigan, S. H., Fountain, G., Freeze, M. J., Greathouse, T., Green, J. L., Guo, Y., Hahn, M., Hamilton, D. P., Hamilton, S. A., Hanley, J., Harch, A., Hart, H. M., Hersman, C. B., Hill, A., Hill, M. E., Hinson, D. P., Holdridge, M. E., Horanyi, M., Howard, A. D., Howett, C. J. A., Jackman, C., Jacobson, R. A., Jennings, D. E., Kammer, J. A., Kang, H. K., Kaufmann, D. E., Kollmann, P., Krimigis, S. M., Kusnierkiewicz, D., Lauer, T. R., Lee, J. E., Lindstrom, K. L., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mallder, V. A., Martin, N., McComas, D. J., McNutt Jr., R. L., Mehoke, D., Mehoke, T., Melin, E. D., Mutchler, M., Nelson, D., Nimmo, F., Nunez, J. I., Ocampo, A., Owen, W. M., Paetzold, M., Page, B., Parker, A. H., Parker, J. W., Pelletier, F., Peterson, J., Pinkine, N., Piquette, M., Porter, S. B., Protopapa, S., Redfern, J., Reitsema, H. J., Reuter, D. C., Roberts, J. H., Robbins, S. J., Rogers, G., Rose, D., Runyon, K., Retherford, K. D., Ryschkewitsch, M. G., Schenk, P., Schindhelm, R., Sepan, B., Showalter, M. R., Singer, K. N., Soluri, M., Stanbridge, D., Steffl, A. J., Strobel, D. F., Stryk, T., Summers, M. E., Szalay, J. R., Tapley, M., Taylor, A., Taylor, H., Throop, H. B., Tsang, C. C. C., Tyler, G. L., Umurhan, O. M., Verbiscer, A. J., Versteeg, M. H., Vincent, M., Webbert, R., Weidner, S., Weigle II, G. E., White, O. L., Whittenburg, K., Williams, B. G., Williams, K., Williams, S., Woods, W. W., Zangari, A. M., and Zirnstein, E.
Abstract: The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition, its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected., Comment: 8 pages - Initial Science paper from NASA's New Horizons Pluto Encounter
Published: 2015
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