Effect of UV radiation on the spectral fingerprints of earth-like planets orbiting M stars
File(s)
Published version
Author(s)
Rugheimer, S
Kaltenegger, L
Segura, A
Linsky, J
Mohanty, S
Type
Journal Article
Abstract
We model the atmospheres and spectra of Earth-like planets orbiting the entire grid of M dwarfs for active and inactive stellar models with Teff = 2300 K to Teff = 3800 K and for six observed MUSCLES M dwarfs with UV radiation data. We set the Earth-like planets at the 1 AU equivalent distance and show spectra from the visible to IR (0.4–20 μm) to compare detectability of features in different wavelength ranges with the James Webb Space Telescope and other future ground- and spaced-based missions to characterize exo-Earths. We focus on the effect of UV activity levels on detectable atmospheric features that indicate habitability on Earth, namely, H2O, O3, CH4, N2O, and CH3Cl. To observe signatures of life—O2/O3 in combination with reducing species like CH4—we find that early and active M dwarfs are the best targets of the M star grid for future telescopes. The O2 spectral feature at 0.76 μm is increasingly difficult to detect in reflected light of later M dwarfs owing to low stellar flux in that wavelength region. N2O, another biosignature detectable in the IR, builds up to observable concentrations in our planetary models around M dwarfs with low UV flux. CH3Cl could become detectable, depending on the depth of the overlapping N2O feature. We present a spectral database of Earth-like planets around cool stars for directly imaged planets as a framework for interpreting future light curves, direct imaging, and secondary eclipse measurements of the atmospheres of terrestrial planets in the habitable zone to design and assess future telescope capabilities.
Date Issued
2015-08-10
Date Acceptance
2015-06-10
Citation
Astrophysical Journal, 2015, 809 (1)
ISSN
1538-4357
Publisher
American Astronomical Society
Journal / Book Title
Astrophysical Journal
Volume
809
Issue
1
Copyright Statement
© 2015 The American Astronomical Society. All rights reserved.
Sponsor
Imperial College Trust
Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council [2006-2012]
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000361653500057&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
N/A
ST/K001051/1
ST/K001051/1
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
astrobiology
planets and satellites: atmospheres
planets and satellites: terrestrial planets
stars: low-mass
EXTRA-SOLAR PLANETS
DIGITAL SKY SURVEY
M-DWARF
HABITABLE ZONE
SUPER-EARTHS
ASTROPHYSICAL PARAMETERS
CHROMOSPHERIC ACTIVITY
ATMOSPHERIC CHEMISTRY
MAGNETIC ACTIVITY
HARPS SEARCH
Astronomy & Astrophysics
0201 Astronomical and Space Sciences
0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
0306 Physical Chemistry (incl. Structural)
Publication Status
Published
Article Number
ARTN 57