Temporal Evolution of the High-energy Irradiation and Water Content of TRAPPIST-1 Exoplanets

  title={Temporal Evolution of the High-energy Irradiation and Water Content of TRAPPIST-1 Exoplanets},
  author={V.Bourrier and Julien de Wit and E.Bolmont and V.Stamenkovic and P.J.Wheatley and Adam J. Burgasser and L.Delrez and B.-O.Demory and D.Ehrenreich and M.Gillon and E.Jehin and J.Leconte and S.M.Lederer and N.Lewis and A.H.M.J.Triaud and Val{\'e}rie Van Grootel},
  journal={The Astronomical Journal},
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… 
Surface and Oceanic Habitability of Trappist-1 Planets under the Impact of Flares.
It is found that for non-oxygenic planets, UV-resistant life-forms would survive on the surface of planets f and g, and more fragile organisms (i.e., Escherichia coli) could be protected from the hazardous UV effects at ocean depths greater than 8 m.
A Coupled Analysis of Atmospheric Mass Loss and Tidal Evolution in XUV Irradiated Exoplanets: The TRAPPIST-1 Case Study
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
Tidal heating and the habitability of the TRAPPIST-1 exoplanets
Context. New estimates of the masses and radii of the seven planets orbiting the ultracool M-dwarf TRAPPIST-1 star permit improved modelling of their compositions, heating by tidal dissipation, and
Water delivery to the TRAPPIST-1 planets
Three of the seven rocky planets (e, f, and g) in TRAPPIST-1 system orbit in the habitable zone of the host star. Therefore, water can be in liquid state at their surface being essential for life.
A Review of Possible Planetary Atmospheres in the TRAPPIST-1 System
It is shown that (i) Hubble Space Telescope transit observations, (ii) bulk density measurements comparison with H2-rich planets mass-radius relationships, (iii) atmospheric escape modelling, and (iv) gas accretion modelling altogether offer solid evidence against the presence of hydrogen-dominated—cloud-free and cloudy—atmospheres around TRAPPIST-1 planets.
Atmospheric reconnaissance of the habitable-zone Earth-sized planets orbiting TRAPPIST-1
Seven temperate Earth-sized exoplanets readily amenable for atmospheric studies transit the nearby ultracool dwarf star TRAPPIST-1 (refs 1,2). Their atmospheric regime is unknown and could range from
Interior Structures and Tidal Heating in the TRAPPIST-1 Planets
With seven planets, the TRAPPIST-1 system has the largest number of exoplanets discovered in a single system so far. The system is of astrobiological interest, because three of its planets orbit in
Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: The TRAPPIST-1 System
The high energy radiation environment around M dwarf stars strongly impacts the characteristics of close-in exoplanet atmospheres, but these wavelengths are difficult to observe due to geocoronal and
The nature of the TRAPPIST-1 exoplanets.
Context. The TRAPPIST-1 system hosts seven Earth-sized, temperate exoplanets orbiting an ultra-cool dwarf star. As such, it represents a remarkable setting to study the formation and evolution of
The high-energy environment and atmospheric escape of the mini-Neptune K2-18 b
K2-18 b is a transiting mini-Neptune that orbits a nearby (38 pc), cool M3 dwarf and is located inside its region of temperate irradiation. We report on the search for hydrogen escape from the


A combined transmission spectrum of the Earth-sized exoplanets TRAPPIST-1 b and c
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.
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.
UV surface habitability of the TRAPPIST-1 system
With the discovery of rocky planets in the temperate habitable zone (HZ) of the close-by cool star TRAPPIST-1 the question of whether such planets could harbour life arises. Habitable planets around
Reconnaissance of the TRAPPIST-1 exoplanet system in the Lyman-α line
The TRAPPIST-1 system offers the opportunity to characterize terrestrial, potentially habitable planets orbiting a nearby ultracool dwarf star. We performed a four-orbit reconnaissance with the Space
Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1
We present an XMM-Newton X-ray observation of TRAPPIST-1, which is an ultracool dwarf star recently discovered to host three transiting and temperate Earth-sized planets. We find the star is a
A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
In the ultraviolet the Neptune-mass exoplanet GJ 436b (also known as Gliese 436b) has transit depths of 56.3 ± 3.5% (1σ), far beyond the 0.69% optical transit depth, and it is inferred that the planet is surrounded and trailed by a large exospheric cloud composed mainly of hydrogen atoms.
Formation of TRAPPIST-1 and other compact systems
TRAPPIST-1 is a nearby 0.08  M ⊙ M-star that was recently found to harbor a planetary system of at least seven Earth-sized planets, all within 0.1 au. The configuration confounds theorists as the
Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
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.
Extreme water loss and abiotic O2 buildup on planets throughout the habitable zones of M dwarfs.
In general, it is found that the initial phase of high luminosity may compromise the habitability of many terrestrial planets orbiting low-mass stars.
Updated Masses for the TRAPPIST-1 Planets
The newly detected TRAPPIST-1 system, with seven low-mass, roughly Earth-sized planets transiting a nearby ultra-cool dwarf, is one of the most important exoplanet discoveries to date. The short