THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS
It is now understood that the accretion of terrestrial planets naturally involves giant collisions, the moon-forming impact being a well-known example. In the aftermath of such collisions, the surface of the surviving planet is very hot and potentially detectable. Here we explore the atmospheric che...
| Main Authors: | , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/92946 https://orcid.org/0000-0002-7791-5124 |
| _version_ | 1826196221351428096 |
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| author | Lupu, R. E. Zahnle, Kevin Marley, Mark S. Schaefer, Laura Fegley, Bruce Morley, Caroline V. Cahoy, Kerri Freedman, Richard S. Fortney, Jonathan J. |
| author2 | Massachusetts Institute of Technology. Department of Aeronautics and Astronautics |
| author_facet | Massachusetts Institute of Technology. Department of Aeronautics and Astronautics Lupu, R. E. Zahnle, Kevin Marley, Mark S. Schaefer, Laura Fegley, Bruce Morley, Caroline V. Cahoy, Kerri Freedman, Richard S. Fortney, Jonathan J. |
| author_sort | Lupu, R. E. |
| collection | MIT |
| description | It is now understood that the accretion of terrestrial planets naturally involves giant collisions, the moon-forming impact being a well-known example. In the aftermath of such collisions, the surface of the surviving planet is very hot and potentially detectable. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting predominantly of CO[subscript 2] and H[subscript 2]O. The atmospheric chemistry and structure are computed self-consistently for atmospheres in equilibrium with hot surfaces with composition reflecting either the bulk silicate Earth (which includes the crust, mantle, atmosphere, and oceans) or Earth's continental crust. We account for all major molecular and atomic opacity sources including collision-induced absorption. We find that these atmospheres are dominated by H[subscript 2]O and CO[subscript 2], while the formation of CH[subscript 4] and NH[subscript 3] is quenched because of short dynamical timescales. Other important constituents are HF, HCl, NaCl, and SO[subscript 2]. These are apparent in the emerging spectra and can be indicative that an impact has occurred. The use of comprehensive opacities results in spectra that are a factor of two lower brightness temperature in the spectral windows than predicted by previous models. The estimated luminosities show that the hottest post-giant-impact planets will be detectable with near-infrared coronagraphs on the planned 30 m class telescopes. The 1-4 μm will be most favorable for such detections, offering bright features and better contrast between the planet and a potential debris disk. We derive cooling timescales on the order of 10[superscript 5-6] yr on the basis of the modeled effective temperatures. This leads to the possibility of discovering tens of such planets in future surveys. |
| first_indexed | 2024-09-23T10:23:26Z |
| format | Article |
| id | mit-1721.1/92946 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:23:26Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/929462022-09-30T20:46:42Z THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS Lupu, R. E. Zahnle, Kevin Marley, Mark S. Schaefer, Laura Fegley, Bruce Morley, Caroline V. Cahoy, Kerri Freedman, Richard S. Fortney, Jonathan J. Massachusetts Institute of Technology. Department of Aeronautics and Astronautics Cahoy, Kerri It is now understood that the accretion of terrestrial planets naturally involves giant collisions, the moon-forming impact being a well-known example. In the aftermath of such collisions, the surface of the surviving planet is very hot and potentially detectable. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting predominantly of CO[subscript 2] and H[subscript 2]O. The atmospheric chemistry and structure are computed self-consistently for atmospheres in equilibrium with hot surfaces with composition reflecting either the bulk silicate Earth (which includes the crust, mantle, atmosphere, and oceans) or Earth's continental crust. We account for all major molecular and atomic opacity sources including collision-induced absorption. We find that these atmospheres are dominated by H[subscript 2]O and CO[subscript 2], while the formation of CH[subscript 4] and NH[subscript 3] is quenched because of short dynamical timescales. Other important constituents are HF, HCl, NaCl, and SO[subscript 2]. These are apparent in the emerging spectra and can be indicative that an impact has occurred. The use of comprehensive opacities results in spectra that are a factor of two lower brightness temperature in the spectral windows than predicted by previous models. The estimated luminosities show that the hottest post-giant-impact planets will be detectable with near-infrared coronagraphs on the planned 30 m class telescopes. The 1-4 μm will be most favorable for such detections, offering bright features and better contrast between the planet and a potential debris disk. We derive cooling timescales on the order of 10[superscript 5-6] yr on the basis of the modeled effective temperatures. This leads to the possibility of discovering tens of such planets in future surveys. United States. National Aeronautics and Space Administration (Origins Program) 2015-01-16T17:43:46Z 2015-01-16T17:43:46Z 2014-02 2013-08 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/92946 Lupu, R. E., Kevin Zahnle, Mark S. Marley, Laura Schaefer, Bruce Fegley, Caroline Morley, Kerri Cahoy, Richard Freedman, and Jonathan J. Fortney. “THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS.” The Astrophysical Journal 784, no. 1 (February 28, 2014): 27. © 2014 The American Astronomical Society https://orcid.org/0000-0002-7791-5124 en_US http://dx.doi.org/10.1088/0004-637x/784/1/27 The 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 American Astronomical Society |
| spellingShingle | Lupu, R. E. Zahnle, Kevin Marley, Mark S. Schaefer, Laura Fegley, Bruce Morley, Caroline V. Cahoy, Kerri Freedman, Richard S. Fortney, Jonathan J. THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS |
| title | THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS |
| title_full | THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS |
| title_fullStr | THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS |
| title_full_unstemmed | THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS |
| title_short | THE ATMOSPHERES OF EARTHLIKE PLANETS AFTER GIANT IMPACT EVENTS |
| title_sort | atmospheres of earthlike planets after giant impact events |
| url | http://hdl.handle.net/1721.1/92946 https://orcid.org/0000-0002-7791-5124 |
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