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Detectability of atmospheric features of Earth-like planets in the habitable zone around M dwarfs

Wunderlich, Fabian and Godolt, Mareike and Grenfell, John Lee and Städt, Steffen and Smith, Alexis M. S. and Gebauer, Stefanie and Schreier, Franz and Hedelt, Pascal and Rauer, Heike (2019) Detectability of atmospheric features of Earth-like planets in the habitable zone around M dwarfs. Astronomy & Astrophysics, 624, pp. 1-17. EDP Sciences. doi: 10.1051/0004-6361/201834504. ISSN 0004-6361.

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Official URL: http://dx.doi.org/10.1051/0004-6361/201834504


Context. The characterisation of the atmosphere of exoplanets is one of the main goals of exoplanet science in the coming decades. Aims. We investigate the detectability of atmospheric spectral features of Earth-like planets in the habitable zone (HZ) around M dwarfs with the future James Webb Space Telescope (JWST). Methods. We used a coupled 1D climate-chemistry-model to simulate the influence of a range of observed and modelled M-dwarf spectra on Earth-like planets. The simulated atmospheres served as input for the calculation of the transmission spectra of the hypothetical planets, using a line-by-line spectral radiative transfer model. To investigate the spectroscopic detectability of absorption bands with JWST we further developed a signal-to-noise ratio (S/N) model and applied it to our transmission spectra. Results. High abundances of methane (CH4) and water (H2O) in the atmosphere of Earth-like planets around mid to late M dwarfs increase the detectability of the corresponding spectral features compared to early M-dwarf planets. Increased temperatures in the middle atmosphere of mid- to late-type M-dwarf planets expand the atmosphere and further increase the detectability of absorption bands. To detect CH4, H2O, and carbon dioxide (CO2) in the atmosphere of an Earth-like planet around a mid to late M dwarf observing only one transit with JWST could be enough up to a distance of 4 pc and less than ten transits up to a distance of 10 pc. As a consequence of saturation limits of JWST and less pronounced absorption bands, the detection of spectral features of hypothetical Earth-like planets around most early M dwarfs would require more than ten transits. We identify 276 existing M dwarfs (including GJ 1132, TRAPPIST-1, GJ 1214, and LHS 1140) around which atmospheric absorption features of hypothetical Earth-like planets could be detected by co-adding just a few transits. Conclusions. The TESS satellite will likely find new transiting terrestrial planets within 15 pc from the Earth. We show that using transmission spectroscopy, JWST could provide enough precision to be able to partly characterise the atmosphere of TESS findings with an Earth-like composition around mid to late M dwarfs.

Item URL in elib:https://elib.dlr.de/127614/
Document Type:Article
Title:Detectability of atmospheric features of Earth-like planets in the habitable zone around M dwarfs
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Wunderlich, Fabianfabian.wunderlich (at) dlr.deUNSPECIFIED
Godolt, Mareikemareike.godolt (at) dlr.deUNSPECIFIED
Grenfell, John Leelee.grenfell (at) dlr.deUNSPECIFIED
Städt, SteffenSteffen.Staedt (at) dlr.deUNSPECIFIED
Smith, Alexis M. S.alexis.smith (at) dlr.deUNSPECIFIED
Gebauer, StefanieStefanie.Gebauer (at) dlr.deUNSPECIFIED
Schreier, FranzFranz.Schreier (at) dlr.dehttps://orcid.org/0000-0001-7196-6599
Hedelt, PascalPascal.Hedelt (at) dlr.dehttps://orcid.org/0000-0002-1752-0040
Rauer, HeikeHeiker.Rauer (at) dlr.deUNSPECIFIED
Date:April 2019
Journal or Publication Title:Astronomy & Astrophysics
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
DOI :10.1051/0004-6361/201834504
Page Range:pp. 1-17
Publisher:EDP Sciences
Keywords:planets and satellites: terrestrial planets, techniques: spectroscopic, stars: low-mass
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Space Exploration
DLR - Research theme (Project):R - Vorhaben Planetary Evolution and Life (old)
Location: Berlin-Adlershof , Oberpfaffenhofen
Institutes and Institutions:Institute of Planetary Research > Extrasolar Planets and Atmospheres
Remote Sensing Technology Institute > Atmospheric Processors
Deposited By: Grenfell, John Lee
Deposited On:14 Jun 2019 09:03
Last Modified:31 Jul 2019 20:25

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