UV surface habitability of the TRAPPIST-1 system

O’Malley-James, Jack T.; Kaltenegger, Lisa

doi:10.1093/mnrasl/slx047

Cited by 80 publications

(26 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Among the most promising systems with planets in the HZ of low mass stars is the nearby TRAPPIST-1 system, located 12 pc away, discovered by Gillon et al (2016Gillon et al ( , 2017; Luger et al (2017) and composed of at least seven rocky planets with three of them in the HZ. The system's host star, TRAPPIST-1, is an active late M-dwarf (OMalley-James & Kaltenegger 2017;Wheatley et al 2017;Vida & Roettenbacher 2018) whose stellar flares could bathe the planetary environment with high energy radiation and plasma, creating severe obstacles to retaining an atmosphere or sustaining habitable conditions on their surface. Despite these difficult conditions, Bolmont et al (2017), Bourrier et al (2017) and Dong et al (2018) have argued that the TRAPPIST-1 planets could retain surface liquid water if they were formed with abundant initial water endowment.…”

Section: Introductionmentioning

confidence: 99%

Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System

Fauchez

Turbet

Villanueva

et al. 2019

ApJ

137

202

View full text Add to dashboard Cite

The TRAPPIST-1 system, consisting of an ultra-cool host star having seven known Earth-size planets will be a prime target for atmospheric characterization with JWST. However, the detectability of atmospheric molecular species may be severely impacted by the presence of clouds and/or hazes. In this work, we perform 3-D General Circulation Model (GCM) simulations with the LMD Generic model supplemented by 1-D photochemistry simulations at the terminator with the Atmos model to simulate several possible atmospheres for TRAPPIST-1e, 1f and 1g: 1) modern 2 Fauchez et al.Earth, 2) Archean Earth, and 3) CO 2 -rich atmospheres. JWST synthetic transit spectra were computed using the GSFC Planetary Spectrum Generator (PSG). We find that TRAPPIST-1e, 1f and 1g atmospheres, with clouds and/or hazes, could be detected using JWST's NIRSpec prism from the CO 2 absorption line at 4.3 µm in less than 15 transits at 3 σ or less than 35 transits at 5 σ. However, our analysis suggests that other gases would require hundreds (or thousands) of transits to be detectable. We also find that H 2 O, mostly confined in the lower atmosphere, is very challenging to detect for these planets or similar systems if the planets' atmospheres are not in a moist greenhouse state. This result demonstrates that the use of GCMs, self-consistently taking into account the effect of clouds and sub-saturation, is crucial to evaluate the detectability of atmospheric molecules of interest as well as for interpreting future detections in a more global (and thus robust and relevant) approach.

show abstract

Section: Introductionmentioning

confidence: 99%

Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System

Fauchez

Turbet

Villanueva

et al. 2019

ApJ

137

202

View full text Add to dashboard Cite

show abstract

“…TRAPPIST-1 is an active M dwarf star (O'Malley-James and Kaltenegger, 2017;Wheatley et al, 2017;Vida and Roettenbacher, 2018) which offers an environment very hostile to the survival of planetary atmospheres. However, Bolmont et al (2017) and Bourrier et al (2017) argued that depending on their initial water contents, the TRAPPIST-1 planets could have retained some water presently.…”

Section: Introductionmentioning

confidence: 99%

TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI): motivations and protocol version 1.0

et al. 2020

View full text Add to dashboard Cite

Upcoming telescopes such as the James Webb Space Telescope (JWST), the European Extremely Large Telescope (E-ELT), the Thirty Meter Telescope (TMT) or the Giant Magellan Telescope (GMT) may soon be able to characterize, through transmission, emission or reflection spectroscopy, the atmospheres of rocky exoplanets orbiting nearby M dwarfs. One of the most promising candidates is the late M dwarf system TRAPPIST-1 which has seven known transiting planets for which Transit Timing Variation (TTV) measurements suggest that they are terrestrial in nature, with a possible enrichment in volatiles.Among these seven planets, TRAPPIST-1e seems to be the most promising candidate to have habitable surface conditions, receiving ∼ 66% of the Earth's incident radiation, and thus needing only modest greenhouse gas inventories to raise surface temperatures to allow surface liquid water to exist. TRAPPIST-1e is therefore one of the prime targets for JWST atmospheric characterization. In this context, the modeling of its potential atmosphere is an essential step prior to observation. Global Climate Models (GCMs) offer the most detailed way to simulate planetary atmospheres. However, intrinsic differences exist between GCMs which can lead to different climate prediction and thus observability of gas and/or cloud features in transmission and thermal emission spectra. Such differences should preferably be known prior to observations. In this paper we present a protocol to inter-compare planetary GCMs. Four testing cases are considered for TRAPPIST-1e but the methodology is applicable to other rocky exoplanets in the Habitable Zone. The four test cases included two land planets composed with 1 a modern Earth and pure CO 2 atmospheres, respectively, and two aqua planets with the same atmospheric compositions.Currently, there are four participating models (LMDG, ROCKE-3D, ExoCAM, UM), however this protocol is intended to let other teams participate as well.

show abstract

“…Although the parameters of the TRAPPIST-1 planets remain dependent on the parameters of their host star, we can nevertheless compare the planets to one another. Furthermore, the planets have emerged from the same nebular environment, have experienced a similar history in terms of irradiation (notably in the XUV range; Wheatley et al 2017;Bourrier et al 2017;O'Malley-James & Kaltenegger 2017), and similar volatile delivery and atmospheric sculpting via cometary impacts (Kral et al submitted). Thus, any differences among the planets must be the result of distinctions in their development.…”

Section: Introductionmentioning

confidence: 99%

Early 2017 observations of TRAPPIST-1 with Spitzer

Delrez

Gillon

Triaud

et al. 2018

Monthly Notices of the Royal Astronomical Society

122

146

View full text Add to dashboard Cite

The recently detected TRAPPIST-1 planetary system, with its seven planets transiting a nearby ultracool dwarf star, offers the first opportunity to perform comparative exoplanetology of temperate Earth-sized worlds. To further advance our understanding of these planets' compositions, energy budgets, and dynamics, we are carrying out an intensive photometric monitoring campaign of their transits with the Spitzer Space Telescope. In this context, we present 60 new transits of the TRAPPIST-1 planets observed with Spitzer /IRAC in February and March 2017. We combine these observations with previously published Spitzer transit photometry and perform a global analysis of the resulting extensive dataset. This analysis refines the transit parameters and provides revised values for the planets' physical parameters, notably their radii, using updated properties for the star. As part of our study, we also measure precise transit timings that will be used in a companion paper to refine the planets' masses and compositions using the transit timing variations method. TRAPPIST-1 shows a very low level of low-frequency variability in the IRAC 4.5-µm band, with a photometric RMS of only 0.11% at a 123-s cadence. We do not detect any evidence of a (quasi-)periodic signal related to stellar rotation. We also analyze the transit light curves individually, to search for possible variations in the transit parameters of each planet due to stellar variability, and find that the Spitzer transits of the planets are mostly immune to the effects of stellar variations. These results are encouraging for forthcoming transmission spectroscopy observations of the TRAPPIST-1 planets with the James Webb Space Telescope.

show abstract

UV surface habitability of the TRAPPIST-1 system

Cited by 80 publications

References 40 publications

Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System

Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System

TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI): motivations and protocol version 1.0

Early 2017 observations of TRAPPIST-1 with Spitzer

Contact Info

Product

Resources

About