Near-infrared study of Titan's resolved disk in spectro-imaging with CFHT/OASIS
International audience We present observations of Titan taken on November 17, 2000, with the near-infrared spectro-imaging system OASIS, mounted downstream of the CFHT/PUEO adaptive optics system. We have spatially resolved Titan's disk at Greatest Eastern Elongation. Our spectra cover the 0.86...
Published in: | Planetary and Space Science |
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Main Authors: | , , , , , , , |
Other Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2005
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Subjects: | |
Online Access: | https://hal.science/hal-00077307 https://doi.org/10.1016/j.pss.2004.08.006 |
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ftuniversailles:oai:HAL:hal-00077307v1 |
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Open Polar |
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Université de Versailles Saint-Quentin-en-Yvelines: HAL-UVSQ |
op_collection_id |
ftuniversailles |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Hirtzig, M. Coustenis, A. Lai, Olivier Emsellem, Eric Pecontal, Arlette Rannou, Pascal Negrao, A. Schmitt, B. Near-infrared study of Titan's resolved disk in spectro-imaging with CFHT/OASIS |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience We present observations of Titan taken on November 17, 2000, with the near-infrared spectro-imaging system OASIS, mounted downstream of the CFHT/PUEO adaptive optics system. We have spatially resolved Titan's disk at Greatest Eastern Elongation. Our spectra cover the 0.86– range with a spectral resolution of 1800. By studying Titan at these wavelengths, we have recovered several pieces of information on the vertical and latitudinal structure of the atmosphere and surface of the satellite. The observing conditions were sufficiently good (AO-corrected seeing of 0.34”) so as to allow us to separate the disk into 7 independent elements. From the flux contained in the methane band, we find that at higher altitudes on Titan, the North–South asymmetry is undergoing changes with respect to previous years when the South was much brighter than the North. This asymmetry still prevails in the troposphere, but at higher levels the well-known “Titan smile”—previously reported—disappears. We believe that we even have evidence for a reversal. The year 2000 may then represent the beginning of a seasonal change in Titan's haze distribution in the near-infrared, something which has been confirmed since but was not visible in the previous years. By comparing regions on Titan's disk with similar surface and stratospheric characteristics, we find an differences in the latitudinal distribution of the aerosol content in the intermediate altitude levels. Reflectivity measurements derived in the window (and hence pertaining to the surface conditions) show that the equatorial regions of the leading side are brighter than the surrounding areas, due to the presence of the large bright zone observed since 1994. Given our spatial resolution, we find this region to be 6% brighter than northern latitudes, 7% brighter than the South pole and in total we have a contrast of 9% between the darker and the brighter areas distinguishable on our images. The methane window yields a geometric albedo of about 0.26 for the bright ... |
author2 |
Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA) Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS) Centre de Recherche Astrophysique de Lyon (CRAL) École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL) Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Service d'aéronomie (SA) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Laboratoire de Planétologie de Grenoble (LPG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Hirtzig, M. Coustenis, A. Lai, Olivier Emsellem, Eric Pecontal, Arlette Rannou, Pascal Negrao, A. Schmitt, B. |
author_facet |
Hirtzig, M. Coustenis, A. Lai, Olivier Emsellem, Eric Pecontal, Arlette Rannou, Pascal Negrao, A. Schmitt, B. |
author_sort |
Hirtzig, M. |
title |
Near-infrared study of Titan's resolved disk in spectro-imaging with CFHT/OASIS |
title_short |
Near-infrared study of Titan's resolved disk in spectro-imaging with CFHT/OASIS |
title_full |
Near-infrared study of Titan's resolved disk in spectro-imaging with CFHT/OASIS |
title_fullStr |
Near-infrared study of Titan's resolved disk in spectro-imaging with CFHT/OASIS |
title_full_unstemmed |
Near-infrared study of Titan's resolved disk in spectro-imaging with CFHT/OASIS |
title_sort |
near-infrared study of titan's resolved disk in spectro-imaging with cfht/oasis |
publisher |
HAL CCSD |
publishDate |
2005 |
url |
https://hal.science/hal-00077307 https://doi.org/10.1016/j.pss.2004.08.006 |
genre |
South pole |
genre_facet |
South pole |
op_source |
ISSN: 0032-0633 Planetary and Space Science https://hal.science/hal-00077307 Planetary and Space Science, 2005, 53, pp.535-556. ⟨10.1016/j.pss.2004.08.006⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.pss.2004.08.006 hal-00077307 https://hal.science/hal-00077307 doi:10.1016/j.pss.2004.08.006 |
op_doi |
https://doi.org/10.1016/j.pss.2004.08.006 |
container_title |
Planetary and Space Science |
container_volume |
53 |
container_issue |
5 |
container_start_page |
535 |
op_container_end_page |
556 |
_version_ |
1799467021980663808 |
spelling |
ftuniversailles:oai:HAL:hal-00077307v1 2024-05-19T07:48:42+00:00 Near-infrared study of Titan's resolved disk in spectro-imaging with CFHT/OASIS Hirtzig, M. Coustenis, A. Lai, Olivier Emsellem, Eric Pecontal, Arlette Rannou, Pascal Negrao, A. Schmitt, B. Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA) Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS) Centre de Recherche Astrophysique de Lyon (CRAL) École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL) Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Service d'aéronomie (SA) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) Laboratoire de Planétologie de Grenoble (LPG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) 2005 https://hal.science/hal-00077307 https://doi.org/10.1016/j.pss.2004.08.006 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.pss.2004.08.006 hal-00077307 https://hal.science/hal-00077307 doi:10.1016/j.pss.2004.08.006 ISSN: 0032-0633 Planetary and Space Science https://hal.science/hal-00077307 Planetary and Space Science, 2005, 53, pp.535-556. ⟨10.1016/j.pss.2004.08.006⟩ [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2005 ftuniversailles https://doi.org/10.1016/j.pss.2004.08.006 2024-04-25T00:14:31Z International audience We present observations of Titan taken on November 17, 2000, with the near-infrared spectro-imaging system OASIS, mounted downstream of the CFHT/PUEO adaptive optics system. We have spatially resolved Titan's disk at Greatest Eastern Elongation. Our spectra cover the 0.86– range with a spectral resolution of 1800. By studying Titan at these wavelengths, we have recovered several pieces of information on the vertical and latitudinal structure of the atmosphere and surface of the satellite. The observing conditions were sufficiently good (AO-corrected seeing of 0.34”) so as to allow us to separate the disk into 7 independent elements. From the flux contained in the methane band, we find that at higher altitudes on Titan, the North–South asymmetry is undergoing changes with respect to previous years when the South was much brighter than the North. This asymmetry still prevails in the troposphere, but at higher levels the well-known “Titan smile”—previously reported—disappears. We believe that we even have evidence for a reversal. The year 2000 may then represent the beginning of a seasonal change in Titan's haze distribution in the near-infrared, something which has been confirmed since but was not visible in the previous years. By comparing regions on Titan's disk with similar surface and stratospheric characteristics, we find an differences in the latitudinal distribution of the aerosol content in the intermediate altitude levels. Reflectivity measurements derived in the window (and hence pertaining to the surface conditions) show that the equatorial regions of the leading side are brighter than the surrounding areas, due to the presence of the large bright zone observed since 1994. Given our spatial resolution, we find this region to be 6% brighter than northern latitudes, 7% brighter than the South pole and in total we have a contrast of 9% between the darker and the brighter areas distinguishable on our images. The methane window yields a geometric albedo of about 0.26 for the bright ... Article in Journal/Newspaper South pole Université de Versailles Saint-Quentin-en-Yvelines: HAL-UVSQ Planetary and Space Science 53 5 535 556 |