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9 results on '"Teanby, N"'

1. Variability in Titan's Mesospheric HCN and Temperature Structure as Observed by ALMA

Author

Thelen, A. E., Nixon, C. A., Cosentino, R., Cordiner, M. A., Teanby, N. A., Newman, C. E., Irwin, P. G. J., and Charnley, S. B.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Physics - Atmospheric and Oceanic Physics
Abstract

The temperature structure of Titan's upper atmosphere exhibits large variability resulting from numerous spatially and temporally irregular external energy sources, seasonal changes, and the influence of molecular species produced via photochemistry. In particular, Titan's relatively abundant HCN is thought to provide substantial cooling to the upper atmosphere through rotational emission, balancing UV/EUV heating and thermal conduction. Here, we present the analysis of ALMA observations of Titan from 2012, 2014, 2015, and 2017, corresponding to planetocentric solar longitudes of ~34-89$^{\circ}$, including vertical HCN and temperature profiles retrieved from the lower mesosphere through the thermosphere (~350-1200 km; $3\times10^{-2}$-$2\times10^{-8}$ mbar). Throughout the atmosphere, temperature profiles differ by 10 to 30 K between observations approximately one Earth year apart, particularly from 600-900 km. We find evidence for a large imbalance in Titan's upper atmospheric energy budget between 2014 and 2015, where the mesospheric thermal structure changes significantly and marks the transition between a mesopause located at ~600 km ($2\times10^{-4}$ mbar) and at ~800 km ($3\times10^{-6}$ mbar). The retrieved HCN abundances vary dramatically during the 2012 to 2017 time period as well, showing close to 2 orders of magnitude difference in abundance at 1000 km. However, the change in HCN abundance does not appear to fully account for the variation in mesospheric temperatures over the $L_S\sim$34-89$^{\circ}$ period. These measurements provide additional insight into the variability of Titan's mesospheric composition and thermal structure following its 2009 vernal equinox, and motivate continued investigation of the origins of such rapid changes in Titan's atmosphere throughout its seasonal cycle., Comment: Published in the Planetary Science Journal. 25 pages, 11 figures, 1 table

Published
2024
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2. Latitudinal Variations in Methane Abundance, Aerosol Opacity and Aerosol Scattering Efficiency in Neptune's Atmosphere Determined From VLT/MUSE

Author

Irwin, P. G. J., primary, Dobinson, J., additional, James, A., additional, Wong, M. H., additional, Fletcher, L. N., additional, Roman, M. T., additional, Teanby, N. A., additional, Toledo, D., additional, Orton, G. S., additional, Pérez‐Hoyos, S., additional, Sánchez‐Lavega, A., additional, Simon, A., additional, Morales‐Juberias, R., additional, and de Pater, I., additional

Published
2023
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3. Largest recent impact craters on Mars: Orbital imaging and surface seismic co-investigation

Author

Posiolova, L. V., primary, Lognonné, P., additional, Banerdt, W. B., additional, Clinton, J., additional, Collins, G. S., additional, Kawamura, T., additional, Ceylan, S., additional, Daubar, I. J., additional, Fernando, B., additional, Froment, M., additional, Giardini, D., additional, Malin, M. C., additional, Miljković, K., additional, Stähler, S. C., additional, Xu, Z., additional, Banks, M. E., additional, Beucler, É., additional, Cantor, B. A., additional, Charalambous, C., additional, Dahmen, N., additional, Davis, P., additional, Drilleau, M., additional, Dundas, C. M., additional, Durán, C., additional, Euchner, F., additional, Garcia, R. F., additional, Golombek, M., additional, Horleston, A., additional, Keegan, C., additional, Khan, A., additional, Kim, D., additional, Larmat, C., additional, Lorenz, R., additional, Margerin, L., additional, Menina, S., additional, Panning, M., additional, Pardo, C., additional, Perrin, C., additional, Pike, W. T., additional, Plasman, M., additional, Rajšić, A., additional, Rolland, L., additional, Rougier, E., additional, Speth, G., additional, Spiga, A., additional, Stott, A., additional, Susko, D., additional, Teanby, N. A., additional, Valeh, A., additional, Werynski, A., additional, Wójcicka, N., additional, and Zenhäusern, G., additional

Published
2022
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5. Hazy Blue Worlds: A Holistic Aerosol Model for Uranus and Neptune, Including Dark Spots

Author

Física aplicada I, Fisika aplikatua I, Irwin, P. G. J., Teanby, N. A., Fletcher, L. N., Toledo, D., Orton, G. S., Wong, M. H., Roman, M. T., Pérez Hoyos, Santiago, James, A., Dobinson, J., Física aplicada I, Fisika aplikatua I, Irwin, P. G. J., Teanby, N. A., Fletcher, L. N., Toledo, D., Orton, G. S., Wong, M. H., Roman, M. T., Pérez Hoyos, Santiago, James, A., and Dobinson, J.

Abstract

We present a reanalysis (using the Minnaert limb-darkening approximation) of visible/near-infrared (0.3-2.5 mu m) observations of Uranus and Neptune made by several instruments. We find a common model of the vertical aerosol distribution i.e., consistent with the observed reflectivity spectra of both planets, consisting of: (a) a deep aerosol layer with a base pressure >5-7 bar, assumed to be composed of a mixture of H2S ice and photochemical haze; (b) a layer of photochemical haze/ice, coincident with a layer of high static stability at the methane condensation level at 1-2 bar; and (c) an extended layer of photochemical haze, likely mostly of the same composition as the 1-2-bar layer, extending from this level up through to the stratosphere, where the photochemical haze particles are thought to be produced. For Neptune, we find that we also need to add a thin layer of micron-sized methane ice particles at similar to 0.2 bar to explain the enhanced reflection at longer methane-absorbing wavelengths. We suggest that methane condensing onto the haze particles at the base of the 1-2-bar aerosol layer forms ice/haze particles that grow very quickly to large size and immediately "snow out" (as predicted by Carlson et al. (1988), ), re-evaporating at deeper levels to release their core haze particles to act as condensation nuclei for H2S ice formation. In addition, we find that the spectral characteristics of "dark spots", such as the Voyager-2/ISS Great Dark Spot and the HST/WFC3 NDS-2018, are well modelled by a darkening or possibly clearing of the deep aerosol layer only.

Published
2022

8. SEIS achievement for Mars Seismology after 1000 sols of seismic monitoring

Author

Lognonne, P., Banerdt, William B., Giardini, D., Panning, M.P., Pike, W.T., Barakoui, S., Böse, Maren, Brinkman, Nienke, Charalambous, C., Compaire, Nicolas, Dahmen, N., Drilleau, M., Fernando, B., Garcia, R., Hobiger, M., Huang, Q., Hurst, K., Jacob, A., Karakostas, F., Kawamura, T., Kedar, S., Khan, A., Kim, D., Knapmeyer‐Endrun, Brigitte, Knapmeyer, Martin, Li, Jiaqi, Menina, S., Murdoch, N., Onodera, K, Perrin, C, Pou, L., Rajsic, A., Samuel, H., Savoie, D., Schimmel, M., Sollberger, D., Stähler, S., Stott, A., Gyalay, S, Van Driel, M., Wojcicka, N., Zweifel, P., Beghein, C., Beucler, E., Antonangeli, D., Banfield, D., Bowles, Neil, Bozdag, E., Christensen, Ulrich, Clinton, J., Collins, G., Daubar, I., Irving, J. C. E., Lorenz, R. D., Margerin, L., Michaut, Chloe, Mimoun, D., Nimmo, Francis, Plesa, Ana-Catalina, Schmerr, N., Smrekar, S., Spiga, A., Teanby, N., Tromp, J., Weber, R., Wieczorek, M., Agard, C., Barrett, Elizabeth, Berenguer, J.L., Ceylan, S., Conejero, V., Duran, C., Froment, M., Horleston, A., Ferrier, C., Fuji, N., Gabsi, T., Gaudin, E., Jaillant, B., Jullien, A., Meunier, F., Pardo, C., ten Pierick, J., Plasman, M., Rochas, L., Sainton, G., Stutzmann, Éléonore, Xu, Z., Yana, Charles, Zenhäusern, Geraldine, and InSight/SEIS, Science Team

Subjects
Mars InSight SEIS
Published
2022

9. Atacama Large Aperture Submillimeter Telescope (AtLAST) science: Planetary and cometary atmospheres.

Author

Cordiner M, Thelen A, Cavalie T, Cosentino R, Fletcher LN, Gurwell M, de Kleer K, Kuan YJ, Lellouch E, Moullet A, Nixon C, de Pater I, Teanby N, Butler B, Charnley S, Milam S, Moreno R, Booth M, Klaassen P, Cicone C, Mroczkowski T, Di Mascolo L, Johnstone D, van Kampen E, Lee M, Liu D, Maccarone T, Saintonge A, Smith M, and Wedemeyer S

Abstract

The study of planets and small bodies within our Solar System is fundamental for understanding the formation and evolution of the Earth and other planets. Compositional and meteorological studies of the giant planets provide a foundation for understanding the nature of the most commonly observed exoplanets, while spectroscopic observations of the atmospheres of terrestrial planets, moons, and comets provide insights into the past and present-day habitability of planetary environments, and the availability of the chemical ingredients for life. While prior and existing (sub)millimeter observations have led to major advances in these areas, progress is hindered by limitations in the dynamic range, spatial and temporal coverage, as well as sensitivity of existing telescopes and interferometers. Here, we summarize some of the key planetary science use cases that factor into the design of the Atacama Large Aperture Submillimeter Telescope (AtLAST), a proposed 50-m class single dish facility: (1) to more fully characterize planetary wind fields and atmospheric thermal structures, (2) to measure the compositions of icy moon atmospheres and plumes, (3) to obtain detections of new, astrobiologically relevant gases and perform isotopic surveys of comets, and (4) to perform synergistic, temporally-resolved measurements in support of dedicated interplanetary space missions. The improved spatial coverage (several arcminutes), resolution (~ 1.2'' - 12''), bandwidth (several tens of GHz), dynamic range (~ 10 5 ) and sensitivity (~ 1 mK km s -1 ) required by these science cases would enable new insights into the chemistry and physics of planetary environments, the origins of prebiotic molecules and the habitability of planetary systems in general., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Cordiner M et al.)

Published
2024
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