The High Albedo of the Hot Jupiter Kepler-7 B
Hot Jupiters are expected to be dark from both observations (albedo upper limits) and theory (alkali metals and/or TiO and VO absorption). However, only a handful of hot Jupiters have been observed with high enough photometric precision at visible wavelengths to investigate these expectations. The N...
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| Format: | Article |
| Language: | en_US |
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IOP Publishing
2012
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| Online Access: | http://hdl.handle.net/1721.1/74166 https://orcid.org/0000-0002-6892-6948 |
| _version_ | 1811095003355676672 |
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| author | Demory, Brice-Olivier Seager, Sara |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Demory, Brice-Olivier Seager, Sara |
| author_sort | Demory, Brice-Olivier |
| collection | MIT |
| description | Hot Jupiters are expected to be dark from both observations (albedo upper limits) and theory (alkali metals and/or TiO and VO absorption). However, only a handful of hot Jupiters have been observed with high enough photometric precision at visible wavelengths to investigate these expectations. The NASA Kepler mission provides a means to widen the sample and to assess the extent to which hot Jupiter albedos are low. We present a global analysis of Kepler-7 b based on Q0-Q4 data, published radial velocities, and asteroseismology constraints. We measure an occultation depth in the Kepler bandpass of 44 ± 5 ppm. If directly related to the albedo, this translates to a Kepler geometric albedo of 0.32 ± 0.03, the most precise value measured so far for an exoplanet. We also characterize the planetary orbital phase light curve with an amplitude of 42 ± 4 ppm. Using atmospheric models, we find it unlikely that the high albedo is due to a dominant thermal component and propose two solutions to explain the observed planetary flux. First, we interpret the Kepler-7 b albedo as resulting from an excess reflection over what can be explained solely by Rayleigh scattering, along with a nominal thermal component. This excess reflection might indicate the presence of a cloud or haze layer in the atmosphere, motivating new modeling and observational efforts. Alternatively, the albedo can be explained by Rayleigh scattering alone if Na and K are depleted in the atmosphere by a factor of 10-100 below solar abundances. |
| first_indexed | 2024-09-23T16:08:59Z |
| format | Article |
| id | mit-1721.1/74166 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:08:59Z |
| publishDate | 2012 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/741662022-10-02T06:38:46Z The High Albedo of the Hot Jupiter Kepler-7 B Demory, Brice-Olivier Seager, Sara Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Demory, Brice-Olivier Seager, Sara Hot Jupiters are expected to be dark from both observations (albedo upper limits) and theory (alkali metals and/or TiO and VO absorption). However, only a handful of hot Jupiters have been observed with high enough photometric precision at visible wavelengths to investigate these expectations. The NASA Kepler mission provides a means to widen the sample and to assess the extent to which hot Jupiter albedos are low. We present a global analysis of Kepler-7 b based on Q0-Q4 data, published radial velocities, and asteroseismology constraints. We measure an occultation depth in the Kepler bandpass of 44 ± 5 ppm. If directly related to the albedo, this translates to a Kepler geometric albedo of 0.32 ± 0.03, the most precise value measured so far for an exoplanet. We also characterize the planetary orbital phase light curve with an amplitude of 42 ± 4 ppm. Using atmospheric models, we find it unlikely that the high albedo is due to a dominant thermal component and propose two solutions to explain the observed planetary flux. First, we interpret the Kepler-7 b albedo as resulting from an excess reflection over what can be explained solely by Rayleigh scattering, along with a nominal thermal component. This excess reflection might indicate the presence of a cloud or haze layer in the atmosphere, motivating new modeling and observational efforts. Alternatively, the albedo can be explained by Rayleigh scattering alone if Na and K are depleted in the atmosphere by a factor of 10-100 below solar abundances. United States. National Aeronautics and Space Administration (Kepler Participating Science Program NNX10AD67G) 2012-10-22T12:58:10Z 2012-10-22T12:58:10Z 2011-06 2011-03 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/74166 Demory, Brice-Olivier et al. “The High Albedo of the Hot Jupiter Kepler-7 B.” The Astrophysical Journal 735.1 (2011): L12. © 2011 IOP Publishing https://orcid.org/0000-0002-6892-6948 en_US http://dx.doi.org/10.1088/2041-8205/735/1/l12 Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing IOP |
| spellingShingle | Demory, Brice-Olivier Seager, Sara The High Albedo of the Hot Jupiter Kepler-7 B |
| title | The High Albedo of the Hot Jupiter Kepler-7 B |
| title_full | The High Albedo of the Hot Jupiter Kepler-7 B |
| title_fullStr | The High Albedo of the Hot Jupiter Kepler-7 B |
| title_full_unstemmed | The High Albedo of the Hot Jupiter Kepler-7 B |
| title_short | The High Albedo of the Hot Jupiter Kepler-7 B |
| title_sort | high albedo of the hot jupiter kepler 7 b |
| url | http://hdl.handle.net/1721.1/74166 https://orcid.org/0000-0002-6892-6948 |
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