Atmospheric escape from the TRAPPIST-1 planets and implications for habitability

@article{Dong2017AtmosphericEF,
  title={Atmospheric escape from the TRAPPIST-1 planets and implications for habitability},
  author={Chuanfei Dong and Meng Jin and Manasvi Lingam and Vladimir S. Airapetian and Yingjuan Ma and Bart van der Holst},
  journal={Proceedings of the National Academy of Sciences},
  year={2017},
  volume={115},
  pages={260 - 265}
}
Significance The search for exoplanets has rapidly emerged as one of the most important endeavors in astronomy. This field received a major impetus with the recent discovery of seven temperate Earth-sized exoplanets orbiting the nearby ultracool dwarf star TRAPPIST-1. One of the most crucial requirements for conventional (surface-based) planetary habitability is the presence of an atmosphere over long timescales. We determine the atmospheric escape rates numerically and analytically for the… 

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References

SHOWING 1-10 OF 72 REFERENCES
A combined transmission spectrum of the Earth-sized exoplanets TRAPPIST-1 b and c
TLDR
Observations of the combined transmission spectrum of the two inner planets during their simultaneous transits on 4 May 2016 rule out cloud-free hydrogen-dominated atmospheres for each planet at ≥10σ levels; TRAPPIST-1 b and c are therefore unlikely to have an extended gas envelope as they occupy a region of parameter space in which high-altitude cloud/haze formation is not expected to be significant for hydrogen- dominated atmospheres.
Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
TLDR
The observations reveal that at least seven planets with sizes and masses similar to those of Earth revolve around TRAPPIST-1, and the six inner planets form a near-resonant chain, such that their orbital periods are near-ratios of small integers.
The Habitability of Planets Orbiting M-dwarf Stars
Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST
Nine transiting Earth-sized planets have recently been discovered around nearby late M dwarfs, including the TRAPPIST-1 planets and two planets discovered by the MEarth survey, GJ 1132b and LHS
Water loss from terrestrial planets orbiting ultracool dwarfs: implications for the planets of TRAPPIST-1
Ultracool dwarfs (UCD) encompass the population of extremely low mass stars (later than M6-type) and brown dwarfs. Because UCDs cool monotonically, their habitable zone (HZ) sweeps inward in time.
Reconnaissance of the TRAPPIST-1 exoplanet system in the Lyman-$\alpha$ line
  • 2017
Enhanced interplanetary panspermia in the TRAPPIST-1 system
  • M. Lingam, A. Loeb
  • Physics, Geology
    Proceedings of the National Academy of Sciences
  • 2017
TLDR
A simple model for estimating the probability of interplanetary panspermia in the recently discovered system of seven planets orbiting the ultracool dwarf star TRAPPIST-1 is presented and it is found that panspermIA is potentially orders of magnitude more likely to occur in the TRAPPist-1 system compared with the Earth-to-Mars case.
Kepler-1649b: An Exo-Venus in the Solar Neighborhood
The Kepler mission has revealed that Earth-sized planets are common, and dozens have been discovered to orbit in or near their host star's habitable zone. A major focus in astronomy is to determine
The Surface UV Environment on Planets Orbiting M Dwarfs: Implications for Prebiotic Chemistry and the Need for Experimental Follow-up
Potentially-habitable planets orbiting M-dwarfs are of intense astrobiological interest because they are the only rocky worlds accessible to biosignature search over the next 10+ years due to a
Temperate Earth-sized planets transiting a nearby ultracool dwarf star
TLDR
Observations of three short-period Earth-sized planets transiting an ultracool dwarf star only 12 parsecs away suggest that 11 orbits remain possible for the third planet, the most likely resulting in irradiation significantly less than that received by Earth.
...
...