Search

Your search keyword '"Wasserman, L.H."' showing total 28 results
Start Over Author "Wasserman, L.H."
28 results on '"Wasserman, L.H."'

5. The mass ratio of Charon to Pluto from Hubble Space Telescope astrometry with the fine guidance sensors

Author

Olkin, C.B., Wasserman, L.H., and Franz, O.G.

Subjects
Charon (Satellite) -- Research, Pluto (Planet) -- Research, Astronomy, Earth sciences
Abstract

The mass ratio of Charon to Pluto is a basic parameter describing the binary system and is necessary for determining the individual masses and densities of these two bodies. Previous measurements of the mass ratio have been made, but the solutions differ significantly (Null et al., 1993; Young et al., 1994; Null and Owen, 1996; Foust et al., 1997; Tholen and Buie, 1997). We present the first observations of Pluto and Charon with a well-calibrated astrometric instrument--the fine guidance sensors on the Hubble Space Telescope. We observed the motion of Pluto and Charon about the system barycenter over 4.4 days (69% of an orbital period) and determined the mass ratio to be 0.122 [+ or -] 0.008 which implies a density of 1.8 to 2.1 g [cm.sup.-3] for Pluto and 1.6 to 1.8 g [cm.sup.-3] for Charon. The resulting rock-mass fractions for Pluto and Charon are higher than expected for bodies formed in the outer solar nebula, possibly indicating significant postaccretion loss of volatiles. Keywords: Pluto; Charon

Published
2003

6. Lower atmosphere and pressure evolution on Pluto from ground-based stellar occultations, 1988-2016

Author

Meza, E. Sicardy, B. Assafin, M. Ortiz, J.L. Bertrand, T. Lellouch, E. Desmars, J. Forget, F. Bérard, D. Doressoundiram, A. Lecacheux, J. Marques Oliveira, J. Roques, F. Widemann, T. Colas, F. Vachier, F. Renner, S. Leiva, R. Braga-Ribas, F. Benedetti-Rossi, G. Camargo, J.I.B. Dias-Oliveira, A. Morgado, B. Gomes-Júnior, A.R. Vieira-Martins, R. Behrend, R. Castro Tirado, A. Duffard, R. Morales, N. Santos-Sanz, P. Jelínek, M. Cunniffe, R. Querel, R. Harnisch, M. Jansen, R. Pennell, A. Todd, S. Ivanov, V.D. Opitom, C. Gillon, M. Jehin, E. Manfroid, J. Pollock, J. Reichart, D.E. Haislip, J.B. Ivarsen, K.M. LaCluyze, A.P. Maury, A. Gil-Hutton, R. Dhillon, V. Littlefair, S. Marsh, T. Veillet, C. Bath, K.-L. Beisker, W. Bode, H.-J. Kretlow, M. Herald, D. Gault, D. Kerr, S. Pavlov, H. Faragó, O. Klös, O. Frappa, E. Lavayssière, M. Cole, A.A. Giles, A.B. Greenhill, J.G. Hill, K.M. Buie, M.W. Olkin, C.B. Young, E.F. Young, L.A. Wasserman, L.H. Devogèle, M. French, R.G. Bianco, F.B. Marchis, F. Brosch, N. Kaspi, S. Polishook, D. Manulis, I. Ait Moulay Larbi, M. Benkhaldoun, Z. Daassou, A. El Azhari, Y. Moulane, Y. Broughton, J. Milner, J. Dobosz, T. Bolt, G. Lade, B. Gilmore, A. Kilmartin, P. Allen, W.H. Graham, P.B. Loader, B. McKay, G. Talbot, J. Parker, S. Abe, L. Bendjoya, P. Rivet, J.-P. Vernet, D. Di Fabrizio, L. Lorenzi, V. Magazzú, A. Molinari, E. Gazeas, K. Tzouganatos, L. Carbognani, A. Bonnoli, G. Marchini, A. Leto, G. Zanmar Sanchez, R. Mancini, L. Kattentidt, B. Dohrmann, M. Guhl, K. Rothe, W. Walzel, K. Wortmann, G. Eberle, A. Hampf, D. Ohlert, J. Krannich, G. Murawsky, G. Gährken, B. Gloistein, D. Alonso, S. Román, A. Communal, J.-E. Jabet, F. DeVisscher, S. Sérot, J. Janik, T. Moravec, Z. MacHado, P. Selva, A. Perelló, C. Rovira, J. Conti, M. Papini, R. Salvaggio, F. Noschese, A. Tsamis, V. Tigani, K. Barroy, P. Irzyk, M. Neel, D. Godard, J.P. Lanoiselée, D. Sogorb, P. Vérilhac, D. Bretton, M. Signoret, F. Ciabattari, F. Naves, R. Boutet, M. De Queiroz, J. Lindner, P. Lindner, K. Enskonatus, P. Dangl, G. Tordai, T. Eichler, H. Hattenbach, J. Peterson, C. Molnar, L.A. Howell, R.R.

Abstract

Context. The tenuous nitrogen (N2) atmosphere on Pluto undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has recently (July 2015) been observed by the New Horizons spacecraft. Aims. The main goals of this study are (i) to construct a well calibrated record of the seasonal evolution of surface pressure on Pluto and (ii) to constrain the structure of the lower atmosphere using a central flash observed in 2015. Methods. Eleven stellar occultations by Pluto observed between 2002 and 2016 are used to retrieve atmospheric profiles (density, pressure, temperature) between altitude levels of ∼5 and ∼380 km (i.e. pressures from ∼10 μbar to 10 nbar). Results. (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N2 ice are derived. (ii) A central flash observed on 2015 June 29 is consistent with New Horizons REX profiles, provided that (a) large diurnal temperature variations (not expected by current models) occur over Sputnik Planitia; and/or (b) hazes with tangential optical depth of ∼0.3 are present at 4-7 km altitude levels; and/or (c) the nominal REX density values are overestimated by an implausibly large factor of ∼20%; and/or (d) higher terrains block part of the flash in the Charon facing hemisphere. © E. Meza et al. 2019.

Published
2019

7. The thermal structure of Triton's atmosphere: results from the 1993 and 1995 occultations

Author

Olkin, C.B., Elliot, J.L., Hammel, H.B., Cooray, A.R., McDonald, S.W., Foust, J.A., Bosh, A.S., Buie, M.W., Millis, R.L., Wasserman, L.H., Dunham, E.W., Young, L.A., Howell, R.R., Hubbard, W.B., Hill, R., Marcialis, R.L., McDonald, J.S., Rank, D.M., Holbrook, J.C., and Reitsema, H.J.

Subjects
Triton (Satellite) -- Observations, Atmosphere -- Analysis, Astronomy, Earth sciences
Abstract

This paper presents new results about Triton's atmospheric structure from the analysis of all ground-based stellar occultation data recorded to date, including one single-chord occultation recorded on 1993 July 10 and nine occultation lightcurves from the double-star event on 1995 August 14. These stellar occultation observations made both in the visible and in the infrared have good spatial coverage of Triton, including the first Triton central-flash observations, and are the first data to probe the altitude level 20-100 km on Triton. The small-planet lightcurve model of J. L. Elliot and L. A. Young (1992, Astron. J. 103, 991-1015) was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude, indicating that Triton's atmosphere is spherically symmetric at [approximately]50-km altitude to within the error of the measurements; however, asymmetry observed in the central flash indicates the atmosphere is not homogeneous at the lowest levels probed ([approximately]20-km altitude). From the average of the 1995 occultation data, the equivalent-isothermal temperature of the atmosphere is 47 [+ or -] 1 K and the atmospheric pressure at 1400-km radius ([approximately]50-km altitude) is 1.4 [+ or -] 0.1 [micro]bar. Both of these are not consistent with a model based on Voyager UVS and RSS observation in 1989 (D. F. Strobel, X. Zhu, M. E. Summers, and M. H. Stevens, 1996, Icarus 120, 266-289). The atmospheric temperature from the occultation is 5 K colder than that predicted by the model and the observed pressure is a factor of 1.8 greater than the model. In our opinion, the disagreement in temperature and pressure is probably due to modeling problems at the microbar level, since measurements at this level have not previously been made. Alternatively, the difference could be due to seasonal change in Triton's atmospheric structure.

Published
1997

8. Pluto's radius and atmosphere: results from the entire 9 June 1988 occultation data set

Author

Millis, R.L., Wasserman, L.H., Franz, O.G., Nye, R.A., Elliot, J.L., Dunham, E.W., Bosh, A.S., Young, L.A., Slivan, S.M., Gilmore, A.C., Kilmartin, P.M., Allen, W.H., Watson, R.D., Dieters, S.W., Hill, K.M., Giles, A.B., Blow, G., Priestley, J., Kissling, W.M., Walker, W.S.G., Marino, B.F., Dix, D.G., Page, A.A., Ross, J.E., and Avey, H.P.

Subjects
Pluto (Planet) -- Surface, Photometry -- Usage, Occultations -- Analysis, Planets -- Atmosphere, Astronomy, Earth sciences
Abstract

The radius of the planet Pluto and its atmospheric composition are determined by photometric observations of the occultation of star P8 by Pluto on Jun 9, 1988. The haze model is used as the basis for determining the parameters and the thermal gradient model is used to explain the obtained results. The radius of the planet is 1195 kilometers. The atmosphere of Pluto is uniform all over the planet.

Published
1993

10. Global warning on Triton

Author

Elliot, J.L., Hammel, H.B., Wasserman, L.H., Franz, O.G., McDonald, S.W., Person, M.J., Olkin, C.B., Dunham, E.W., Spencer, J.R., Stansberry, J.A., Buie, M.W., Pasachoff, J.M., Babcock, B.A., and McConnochie, T.H.

Subjects
Triton (Satellite) -- Research, Global warming -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Triton, the largest moon of Neptune, has experienced a period of global warming since 1989, according to research based on observations of recent stellar occultation. Basic seasonal models of long-term frost migration indicate monotonic long-term transfer of most of Triton's nitrogen frost to the poles, which have the minimum seasonally averaged insolation. It is possible that the observed global warming of Triton is the result of increased insolation of a permanent south polar cap.

Published
1998

11. Results for Titan's atmosphere from its occultation of 28 Sagittarii

Author

Hubbard, W.B., Hunten, D.M., Reitsema, H.J., Brosch, N., Nevo, Y., Carreira, E., Rossi, F., and Wasserman, L.H.

Subjects
Vatican City -- Buildings and facilities, Israel -- Buildings and facilities, Titan (Satellite), Satellites -- Saturn, Occultations -- Observations, Environmental issues, Science and technology, Zoology and wildlife conservation, The University of Arizona. Lunar and Planetary Laboratory -- Research, Lowell Observatory -- Research
Published
1990

12. Evidence that Pluto's atmosphere does not collapse from occultations including the 2013 May 04 event

Author

National Aeronautics and Space Administration (US), Olkin, C.B., Young, L.A., Borncamp, D., Pickles, A., Sicardy, B., Assafin, M., Bianco, F.B., Buie, M.W., De Oliveira, A.D., Gillon, M., French, R.G., Ramos Gomes, A., Jehin, E., Morales, N., Opitom, C., Ortiz, José Luis, Maury, A., Norbury, M., Braga-Ribas, F., Smith, R., Wasserman, L.H., Young, E.F., Zacharias, M., Zacharias, N., National Aeronautics and Space Administration (US), Olkin, C.B., Young, L.A., Borncamp, D., Pickles, A., Sicardy, B., Assafin, M., Bianco, F.B., Buie, M.W., De Oliveira, A.D., Gillon, M., French, R.G., Ramos Gomes, A., Jehin, E., Morales, N., Opitom, C., Ortiz, José Luis, Maury, A., Norbury, M., Braga-Ribas, F., Smith, R., Wasserman, L.H., Young, E.F., Zacharias, M., and Zacharias, N.

Abstract

© 2014 The Authors. Combining stellar occultation observations probing Pluto's atmosphere from 1988 to 2013, and models of energy balance between Pluto's surface and atmosphere, we find the preferred models are consistent with Pluto retaining a collisional atmosphere throughout its 248-year orbit. The occultation results show an increasing atmospheric pressure with time in the current epoch, a trend present only in models with a high thermal inertia and a permanent N2 ice cap at Pluto's north rotational pole.

Published
2015

13. Stardust-NExT, Deep Impact, and the accelerating spin of 9P/Tempel 1

Author

Belton, M.J.S., Meech, K.J., Chesley, S., Pittichová, J., Carcich, B., Drahus, M., Harris, A., Gillam, S., Veverka, J., Mastrodemos, N., Owen, W., A'Hearn, M.F., Bagnulo, S., Bai, J., Barrera, L., Bastien, F., Bauer, J.M., Bedient, J., Bhatt, B.C., Boehnhardt, H., Brosch, N., Buie, M., Candia, P., Chen, W.-P., Chiang, P., Choi, Y.-J., Cochran, A., Crockett, C.J., Duddy, S., Farnham, T., Fernández, Y.R., Gutiérrez, P., Hainaut, O.R., Hampton, D., Herrmann, K.A., Hsieh, H., Kadooka, M.A., Kaluna, H., Keane, J., Kim, M.-J., Klaasen, K., Kleyna, J., Krisciunas, K., Lara, L.M., Lauer, T.R., Li, J.-Y., Licandro, J., Lisse, C.M., Lowry, S.C., McFadden, L., Moskovitz, N., Mueller, B., Polishook, D., Raja, N.S., Riesen, T., Sahu, D.K., Samarasinha, N., Sarid, G., Sekiguchi, T., Sonnett, S., Suntzeff, N.B., Taylor, B.W., Thomas, P., Tozzi, G.P., Vasundhara, R., Vincent, J.-B., Wasserman, L.H., Webster-Schultz, B., Yang, B., Zenn, T., Zhao, H., Belton, M.J.S., Meech, K.J., Chesley, S., Pittichová, J., Carcich, B., Drahus, M., Harris, A., Gillam, S., Veverka, J., Mastrodemos, N., Owen, W., A'Hearn, M.F., Bagnulo, S., Bai, J., Barrera, L., Bastien, F., Bauer, J.M., Bedient, J., Bhatt, B.C., Boehnhardt, H., Brosch, N., Buie, M., Candia, P., Chen, W.-P., Chiang, P., Choi, Y.-J., Cochran, A., Crockett, C.J., Duddy, S., Farnham, T., Fernández, Y.R., Gutiérrez, P., Hainaut, O.R., Hampton, D., Herrmann, K.A., Hsieh, H., Kadooka, M.A., Kaluna, H., Keane, J., Kim, M.-J., Klaasen, K., Kleyna, J., Krisciunas, K., Lara, L.M., Lauer, T.R., Li, J.-Y., Licandro, J., Lisse, C.M., Lowry, S.C., McFadden, L., Moskovitz, N., Mueller, B., Polishook, D., Raja, N.S., Riesen, T., Sahu, D.K., Samarasinha, N., Sarid, G., Sekiguchi, T., Sonnett, S., Suntzeff, N.B., Taylor, B.W., Thomas, P., Tozzi, G.P., Vasundhara, R., Vincent, J.-B., Wasserman, L.H., Webster-Schultz, B., Yang, B., Zenn, T., and Zhao, H.

Abstract

The evolution of the spin rate of Comet 9P/Tempel 1 through two perihelion passages (in 2000 and 2005) is determined from 1922 Earth-based observations taken over a period of 13. year as part of a World-Wide observing campaign and from 2888 observations taken over a period of 50 days from the Deep Impact spacecraft. We determine the following sidereal spin rates (periods): 209.023 ± 0.025°/dy (41.335 ± 0.005. h) prior to the 2000 perihelion passage, 210.448 ± 0.016°/dy (41.055 ± 0.003. h) for the interval between the 2000 and 2005 perihelion passages, 211.856 ± 0.030°/dy (40.783 ± 0.006. h) from Deep Impact photometry just prior to the 2005 perihelion passage, and 211.625 ± 0.012°/dy (40.827 ± 0.002. h) in the interval 2006-2010 following the 2005 perihelion passage. The period decreased by 16.8 ± 0.3. min during the 2000 passage and by 13.7 ± 0.2. min during the 2005 passage suggesting a secular decrease in the net torque. The change in spin rate is asymmetric with respect to perihelion with the maximum net torque being applied on approach to perihelion. The Deep Impact data alone show that the spin rate was increasing at a rate of 0.024 ± 0.003°/dy/dy at JD2453530.60510 (i.e., 25.134 dy before impact), which provides independent confirmation of the change seen in the Earth-based observations.The rotational phase of the nucleus at times before and after each perihelion and at the Deep Impact encounter is estimated based on the Thomas et al. (Thomas et al. [2007]. Icarus 187, 4-15) pole and longitude system. The possibility of a 180° error in the rotational phase is assessed and found to be significant. Analytical and physical modeling of the behavior of the spin rate through of each perihelion is presented and used as a basis to predict the rotational state of the nucleus at the time of the nominal (i.e., prior to February 2010) Stardust-NExT encounter on 2011 February 14 at 20:42.We find that a net torque in the range of 0.3-2.5×107kgm2s-2 acts on the nucleus duri

Published
2011

14. EPOXI: Comet 103P/Hartley 2 observations from a worldwide campaign

Author

Meech, K.J., A'Hearn, M.F., Adams, J.A., Bacci, P., Bai, J., Barrera, L., Battelino, M., Bauer, J.M., Becklin, E., Bhatt, B., Biver, N., Bockelée-Morvan, D., Bodewits, D., Böhnhardt, H., Boissier, J., Bonev, B.P., Borghini, W., Brucato, J.R., Bryssinck, E., Buie, M.W., Canovas, H., Castellano, D., Charnley, S.B., Chen, W.P., Chiang, P., Choi, Y.-J., Christian, D.J., Chuang, Y.-L., Cochran, A.L., Colom, P., Combi, M.R., Coulson, I.M., Crovisier, J., Dello Russo, N., Dennerl, K., DeWahl, K., DiSanti, M.A., Facchini, M., Farnham, T.L., Fernández, Y., Floren, H.G., Frisk, U., Fujiyoshi, T., Furusho, R., Fuse, T., Galli, G., Garci­a-Hernández, D.A., Gersch, A., Getu, Z., Gibb, E.L., Gillon, M., Guido, E., Guillermo, R.A., Hadamcik, E., Hainaut, O., Hammel, H.B., Harker, D.E., Harmon, J.K., Harris, W.M., Hartogh, P., Hashimoto, M., Hausler, B., Herter, T., Hjalmarson, A., Holland, S.T., Honda, M., Hosseini, S., Howell, E.S., Howes, N., Hsieh, H.H., Hsiao, H.-Y., Hutsemékers, D., Immler, S.M., Jackson, W.M., Jeffers, S.V., Jehin, E., Jones, T.J., De Juan Ovelar, M., Kaluna, H.M., Karlsson, T., Kawakita, H., Keane, J.V., Keller, L.D., Kelley, M.S., Kinoshita, D., Kiselev, N.N., Kleyna, J., Knight, M.M., Kobayashi, H., Kobulnicky, H.A., Kolokolova, L., Kreiny, M., Kuan, Y.-J., Küppers, M., Lacruz, J.M., Landsman, W.B., Lara, L.M., Lecacheux, A., Levasseur-Regourd, A.C., Li, B., Licandro, J., Ligustri, R., Lin, Z.-Y., Lippi, M., Lis, D.C., Lisse, C.M., Lovell, A.J., Lowry, S.C., Lu, H., Lundin, S., Magee-Sauer, K., Magain, P., Manfroid, J., Mazzotta Epifani, E., McKay, A., Melita, M.D., Mikuz, H., Milam, S.N., Milani, G., Min, M., Moreno, R., Mueller, B.E.A., Mumma, M.J., Nicolini, M., Nolan, M.C., Nordh, H.L., Nowajewski, P.B., Team, O., Ootsubo, T., Paganini, L., Perrella, C., Pittichová, J., Prosperi, E., Radeva, Y.L., Reach, W.T., Remijan, A.J., Rengel, M., Riesen, T.E., Rodenhuis, M., Rodríguez, D.P., Russell, R.W., Sahu, D.K., Samarasinha, N.H., Sánchez Caso, A., Sandqvist, A., Sarid, G., Sato, M., Schleicher, D.G., Schwieterman, E.W., Sen, A.K., Shenoy, D., Shi, J.-C., Shinnaka, Y., Skvarc, J., Snodgrass, C., Sitko, M.L., Sonnett, S., Sosseini, S., Sostero, G., Sugita, S., Swinyard, B.M., Szutowicz, S., Takato, N., Tanga, P., Taylor, P.A., Tozzi, G.-P., Trabatti, R., Trigo-Rodríguez, J.M., Tubiana, C., De Val-Borro, M., Vacca, W., Vandenbussche, B., Vaubaillion, J., Velichko, F.P., Velichko, S.F., Vervack, R.J., Vidal-Nunez, M.J., Villanueva, G.L., Vinante, C., Vincent, J.-B., Wang, M., Wasserman, L.H., Watanabe, J., Weaver, H.A., Weissman, P.R., Wolk, S., Wooden, D.H., Woodward, C.E., Yamaguchi, M., Yamashita, T., Yanamandra-Fischer, P.A., Yang, B., Yao, J.-S., Yeomans, D.K., Zenn, T., Zhao, H., Ziffer, J.E., Meech, K.J., A'Hearn, M.F., Adams, J.A., Bacci, P., Bai, J., Barrera, L., Battelino, M., Bauer, J.M., Becklin, E., Bhatt, B., Biver, N., Bockelée-Morvan, D., Bodewits, D., Böhnhardt, H., Boissier, J., Bonev, B.P., Borghini, W., Brucato, J.R., Bryssinck, E., Buie, M.W., Canovas, H., Castellano, D., Charnley, S.B., Chen, W.P., Chiang, P., Choi, Y.-J., Christian, D.J., Chuang, Y.-L., Cochran, A.L., Colom, P., Combi, M.R., Coulson, I.M., Crovisier, J., Dello Russo, N., Dennerl, K., DeWahl, K., DiSanti, M.A., Facchini, M., Farnham, T.L., Fernández, Y., Floren, H.G., Frisk, U., Fujiyoshi, T., Furusho, R., Fuse, T., Galli, G., Garci­a-Hernández, D.A., Gersch, A., Getu, Z., Gibb, E.L., Gillon, M., Guido, E., Guillermo, R.A., Hadamcik, E., Hainaut, O., Hammel, H.B., Harker, D.E., Harmon, J.K., Harris, W.M., Hartogh, P., Hashimoto, M., Hausler, B., Herter, T., Hjalmarson, A., Holland, S.T., Honda, M., Hosseini, S., Howell, E.S., Howes, N., Hsieh, H.H., Hsiao, H.-Y., Hutsemékers, D., Immler, S.M., Jackson, W.M., Jeffers, S.V., Jehin, E., Jones, T.J., De Juan Ovelar, M., Kaluna, H.M., Karlsson, T., Kawakita, H., Keane, J.V., Keller, L.D., Kelley, M.S., Kinoshita, D., Kiselev, N.N., Kleyna, J., Knight, M.M., Kobayashi, H., Kobulnicky, H.A., Kolokolova, L., Kreiny, M., Kuan, Y.-J., Küppers, M., Lacruz, J.M., Landsman, W.B., Lara, L.M., Lecacheux, A., Levasseur-Regourd, A.C., Li, B., Licandro, J., Ligustri, R., Lin, Z.-Y., Lippi, M., Lis, D.C., Lisse, C.M., Lovell, A.J., Lowry, S.C., Lu, H., Lundin, S., Magee-Sauer, K., Magain, P., Manfroid, J., Mazzotta Epifani, E., McKay, A., Melita, M.D., Mikuz, H., Milam, S.N., Milani, G., Min, M., Moreno, R., Mueller, B.E.A., Mumma, M.J., Nicolini, M., Nolan, M.C., Nordh, H.L., Nowajewski, P.B., Team, O., Ootsubo, T., Paganini, L., Perrella, C., Pittichová, J., Prosperi, E., Radeva, Y.L., Reach, W.T., Remijan, A.J., Rengel, M., Riesen, T.E., Rodenhuis, M., Rodríguez, D.P., Russell, R.W., Sahu, D.K., Samarasinha, N.H., Sánchez Caso, A., Sandqvist, A., Sarid, G., Sato, M., Schleicher, D.G., Schwieterman, E.W., Sen, A.K., Shenoy, D., Shi, J.-C., Shinnaka, Y., Skvarc, J., Snodgrass, C., Sitko, M.L., Sonnett, S., Sosseini, S., Sostero, G., Sugita, S., Swinyard, B.M., Szutowicz, S., Takato, N., Tanga, P., Taylor, P.A., Tozzi, G.-P., Trabatti, R., Trigo-Rodríguez, J.M., Tubiana, C., De Val-Borro, M., Vacca, W., Vandenbussche, B., Vaubaillion, J., Velichko, F.P., Velichko, S.F., Vervack, R.J., Vidal-Nunez, M.J., Villanueva, G.L., Vinante, C., Vincent, J.-B., Wang, M., Wasserman, L.H., Watanabe, J., Weaver, H.A., Weissman, P.R., Wolk, S., Wooden, D.H., Woodward, C.E., Yamaguchi, M., Yamashita, T., Yanamandra-Fischer, P.A., Yang, B., Yao, J.-S., Yeomans, D.K., Zenn, T., Zhao, H., and Ziffer, J.E.

Abstract

Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was 16.4hr. Starting in 2010 August the period changed from 16.6hr to near 19hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO2-driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production. © 2011. The American Astronomical Society. All rights reserved.

Published
2011

15. Binary Star Astrometry with the Hubble Space Telescope: One Millisecond of ARC Accuracy and Beyond

Author

Franz, O., primary, Kreidl, K.J., additional, Wasserman, L.H., additional, Bradley, A.J., additional, Benedict, G.F., additional, Duncombe, R.L., additional, Hemenway, P.D., additional, Jefferys, W.H., additional, McArthur, B., additional, Nelan, E., additional, Shelus, P.J., additional, Story, D., additional, Whipple, A.L., additional, Fredrick, L.W., additional, and Van Altena, W.F., additional

Published
1995
Full Text
View/download PDF

16. HST in Search of Binaries among Faint Members of the Hyades Cluster

Author

Franz, O., primary, Kreidl, K.J., additional, Wasserman, L.H., additional, Bradley, A.J., additional, Benedict, G.F., additional, Duncombe, R.L., additional, Hemenway, P.D., additional, Jefferys, W.H., additional, McArthur, B., additional, Nelan, E., additional, Shelus, P.J., additional, Story, D., additional, Whipple, A.L., additional, Fredrick, L.W., additional, and Van Altena, W.F., additional

Published
1995
Full Text
View/download PDF

21. The size, shape, density, and Albedo of Ceres from its occultation of BD+8°471

Author

Millis, R.L., Wasserman, L.H., Franz, O.G., Nye, R.A., Oliver, R.C., Kreidl, T.J., Jones, S.E., Hubbard, W., Lebofsky, L., Goff, R., Marcialis, R., Sykes, M., Frecker, J., Hunten, D., Zellner, B., Reitsema, H., Schneider, G., Dunham, E., Klavetter, J., Meech, K., Oswalt, T., Rafert, J., Strother, E., Smith, J., Povenmire, H., Jones, B., Kornbluh, D., Reed, L., Izor, K., A'Hearn, M.F., Schnurr, R., Osborn, W., Parker, D., Douglas, W.T., Beish, J.D., Klemola, A.R., Rios, M., Sanchez, A., Piironen, J., Mooney, M., Ireland, R.S., and Leibow, D.

Abstract

The occultation of BD+8°471 by Ceres on 13 November 1984 was observed photoelectrically at 13 sites in Mexico, Florida, and the Caribbean. These observations indicate that Ceres is an oblate spheroid having an equatorial radius of 479.6±2.4 km and a polar radius of 453.4±4.5 km. The mean density of this minor planet is 2.7 g/cm3±5%, and its visual geometric albedo is 0.073. While the surface appears globally to be in hydrostatic equilibrium, firm evidence of real limb irregularities is seen in the data.

Published
1987
Full Text
View/download PDF

24. Pluto's atmosphere

Author

Elliot, J.L., primary, Dunham, E.W., additional, Bosh, A.S., additional, Slivan, S.M., additional, Young, L.A., additional, Wasserman, L.H., additional, and Millis, R.L., additional

Published
1989
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results