Reference : Temporal Evolution of the High-energy Irradiation and Water Content of TRAPPIST-1 Exo...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/216457
Temporal Evolution of the High-energy Irradiation and Water Content of TRAPPIST-1 Exoplanets
English
Bourrier, V. mailto [Observatoire de l’Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland <ID system="ORCID">0000-0002-9148-034X</ID>]
de Wit, J. [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA <ID system="ORCID">0000-0003-2415-2191</ID>]
Bolmont, E. [Laboratoire AIM Paris-Saclay, CEA/DRF—CNRS—Univ. Paris Diderot—IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex, France]
Stamenković, V. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA <ID system="ORCID">0000-0003-2416-3683</ID>]
Wheatley, P. J. [Department of Physics, University of Warwick, Coventry CV4 7AL, UK <ID system="ORCID">0000-0003-1452-2240</ID>]
Burgasser, A. J. [Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093, USA <ID system="ORCID">0000-0002-6523-9536</ID>]
Delrez, L. [Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE, UK]
Demory, B.-O. [University of Bern, Center for Space and Habitability, Sidlerstrasse 5, CH-3012, Bern, Switzerland <ID system="ORCID">0000-0002-9355-5165</ID>]
Ehrenreich, D. [Observatoire de l’Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland <ID system="ORCID">0000-0001-9704-5405</ID>]
Gillon, Michaël mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa) >]
Jehin, Emmanuel mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa) >]
Leconte, J. [Laboratoire dAstrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, F-33615 Pessac, France]
Lederer, S. M. [NASA Johnson Space Center, 2101 NASA Parkway, Houston, Texas, 77058, USA]
Lewis, N. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218, USA <ID system="ORCID">0000-0002-8507-1304</ID>]
Triaud, A. H. M. J. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK <ID system="ORCID">0000-0002-5510-8751</ID>]
Van Grootel, Valérie mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie >]
1-Sep-2017
Astronomical Journal
Institute of Physics (IoP)
154
Yes (verified by ORBi)
0004-6256
1538-3881
[en] planetary systems ; planets and satellites: atmospheres ; planets and satellites: terrestrial planets ; stars: individual: TRAPPIST-1 ; stars: low-mass ; ultraviolet: planetary systems
[en] The ultracool dwarf star TRAPPIST-1 hosts seven Earth-size transiting planets, some of which could harbor liquid water on their surfaces. Ultraviolet observations are essential to measuring their high-energy irradiation and searching for photodissociated water escaping from their putative atmospheres. Our new observations of the TRAPPIST-1 Lyα line during the transit of TRAPPIST-1c show an evolution of the star emission over three months, preventing us from assessing the presence of an extended hydrogen exosphere. Based on the current knowledge of the stellar irradiation, we investigated the likely history of water loss in the system. Planets b to d might still be in a runaway phase, and planets within the orbit of TRAPPIST-1g could have lost more than 20 Earth oceans after 8 Gyr of hydrodynamic escape. However, TRAPPIST-1e to h might have lost less than three Earth oceans if hydrodynamic escape stopped once they entered the habitable zone (HZ). We caution that these estimates remain limited by the large uncertainty on the planet masses. They likely represent upper limits on the actual water loss because our assumptions maximize the X-rays to ultraviolet-driven escape, while photodissociation in the upper atmospheres should be the limiting process. Late-stage outgassing could also have contributed significant amounts of water for the outer, more massive planets after they entered the HZ. While our results suggest that the outer planets are the best candidates to search for water with the JWST, they also highlight the need for theoretical studies and complementary observations in all wavelength domains to determine the nature of the TRAPPIST-1 planets and their potential habitability.
http://hdl.handle.net/2268/216457
10.3847/1538-3881/aa859c
http://adsabs.harvard.edu/abs/2017AJ....154..121B

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