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Title: A Coupled Analysis of Atmospheric Mass Loss and Tidal Evolution in XUV Irradiated Exoplanets: The TRAPPIST-1 Case Study

Abstract

Exoplanets residing close to their stars can experience evolution of both their physical structures and their orbits due to the influence of their host stars. In this work, we present a coupled analysis of dynamical tidal dissipation and atmospheric mass loss for exoplanets in X-ray and ultraviolet (XUV) irradiated environments. As our primary application, we use this model to study the TRAPPIST-1 system and place constraints on the interior structure and orbital evolution of the planets. We start by reporting on an ultraviolet continuum flux measurement (centered around ∼1900 Å) for the star TRAPPIST-1, based on 300 ks of Neil Gehrels Swift Observatory data, and which enables an estimate of the XUV-driven thermal escape arising from XUV photodissociation for each planet. We find that the X-ray flaring luminosity, measured from our X-ray detections, of TRAPPIST-1 is 5.6 × 10{sup −4} L {sub *}, while the full flux including non-flaring periods is 6.1 × 10{sup −5} L {sub *}, when L {sub *} is TRAPPIST-1's bolometric luminosity. We then construct a model that includes both atmospheric mass loss and tidal evolution and requires the planets to attain their present-day orbital elements during this coupled evolution. We use this model to constrain the ratio Q{sup ′}=3Q/2k{submore » 2} for each planet. Finally, we use additional numerical models implemented with the Virtual Planet Simulator VPLanet to study ocean retention for these planets using our derived system parameters.« less

Authors:
; ;  [1];  [2];  [3]
  1. Department of Astronomy, University of Michigan, Ann Arbor, MI 48104 (United States)
  2. Code 662, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  3. Department of Astronomy, University of Washington, Seattle, WA (United States)
Publication Date:
OSTI Identifier:
23013238
Resource Type:
Journal Article
Journal Name:
Astronomical Journal (New York, N.Y. Online)
Additional Journal Information:
Journal Volume: 159; Journal Issue: 6; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1538-3881
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BOLOMETERS; DISSOCIATION; LUMINOSITY; MASS TRANSFER; ORBITS; PHOTOLYSIS; PLANETS; STAR EVOLUTION; STARS; STELLAR WINDS; ULTRAVIOLET RADIATION; X RADIATION

Citation Formats

Becker, Juliette, Gallo, Elena, Adams, Fred C., Hodges-Kluck, Edmund, and Barnes, Rory. A Coupled Analysis of Atmospheric Mass Loss and Tidal Evolution in XUV Irradiated Exoplanets: The TRAPPIST-1 Case Study. United States: N. p., 2020. Web. doi:10.3847/1538-3881/AB8FB0.
Becker, Juliette, Gallo, Elena, Adams, Fred C., Hodges-Kluck, Edmund, & Barnes, Rory. A Coupled Analysis of Atmospheric Mass Loss and Tidal Evolution in XUV Irradiated Exoplanets: The TRAPPIST-1 Case Study. United States. https://doi.org/10.3847/1538-3881/AB8FB0
Becker, Juliette, Gallo, Elena, Adams, Fred C., Hodges-Kluck, Edmund, and Barnes, Rory. 2020. "A Coupled Analysis of Atmospheric Mass Loss and Tidal Evolution in XUV Irradiated Exoplanets: The TRAPPIST-1 Case Study". United States. https://doi.org/10.3847/1538-3881/AB8FB0.
@article{osti_23013238,
title = {A Coupled Analysis of Atmospheric Mass Loss and Tidal Evolution in XUV Irradiated Exoplanets: The TRAPPIST-1 Case Study},
author = {Becker, Juliette and Gallo, Elena and Adams, Fred C. and Hodges-Kluck, Edmund and Barnes, Rory},
abstractNote = {Exoplanets residing close to their stars can experience evolution of both their physical structures and their orbits due to the influence of their host stars. In this work, we present a coupled analysis of dynamical tidal dissipation and atmospheric mass loss for exoplanets in X-ray and ultraviolet (XUV) irradiated environments. As our primary application, we use this model to study the TRAPPIST-1 system and place constraints on the interior structure and orbital evolution of the planets. We start by reporting on an ultraviolet continuum flux measurement (centered around ∼1900 Å) for the star TRAPPIST-1, based on 300 ks of Neil Gehrels Swift Observatory data, and which enables an estimate of the XUV-driven thermal escape arising from XUV photodissociation for each planet. We find that the X-ray flaring luminosity, measured from our X-ray detections, of TRAPPIST-1 is 5.6 × 10{sup −4} L {sub *}, while the full flux including non-flaring periods is 6.1 × 10{sup −5} L {sub *}, when L {sub *} is TRAPPIST-1's bolometric luminosity. We then construct a model that includes both atmospheric mass loss and tidal evolution and requires the planets to attain their present-day orbital elements during this coupled evolution. We use this model to constrain the ratio Q{sup ′}=3Q/2k{sub 2} for each planet. Finally, we use additional numerical models implemented with the Virtual Planet Simulator VPLanet to study ocean retention for these planets using our derived system parameters.},
doi = {10.3847/1538-3881/AB8FB0},
url = {https://www.osti.gov/biblio/23013238}, journal = {Astronomical Journal (New York, N.Y. Online)},
issn = {1538-3881},
number = 6,
volume = 159,
place = {United States},
year = {2020},
month = {6}
}