The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). Part II: Moist Cases -- The Two Waterworlds

Sergeev, Denis E.; Fauchez, Thomas J.; Turbet, Martin; Boutle, Ian A.; Tsigaridis, Kostas; Way, Michael J.; Wolf, Eric T.; Domagal-Goldman, Shawn D.; Forget, Francois; Haqq-Misra, Jacob; Kopparapu, Ravi K.; Lambert, F. Hugo; Manners, James; Mayne, Nathan J.

doi:10.48550/arxiv.2109.11459

Cited by 9 publications

(9 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…LP 890-9 is the second-coolest star found to host planets after TRAPPIST-1. The seven terrestrial planets orbiting TRAPPIST-1 have garnered the interest of a broad community across very diverse scientific disciplines: planet formation and evolution (e.g., Ormel et al 2017;Coleman et al 2019;Raymond et al 2022), star-planet interactions (e.g., Bolmont et al 2017;O'Malley-James & Kaltenegger 2017;Dong et al 2018), multi-planet dynamics (e.g., Grimm et al 2018;Agol et al 2021;Teyssandier et al 2022), interior modelling (e.g., Dorn et al 2018;Barr et al 2018;Barth et al 2021), atmospheric observations (e.g., de Wit et al 2016Bourrier et al 2017;de Wit et al 2018) and modelling (e.g., Lustig-Yaeger et al 2019;Pidhorodetska et al 2020;Lin et al 2021), or climate predictions (e.g., Turbet et al 2018Turbet et al , 2021Sergeev et al 2021), among others. The discovery of the remarkable LP 890-9 system presented in this work offers another rare opportunity to study temperate terrestrial planets around our smallest and coolest neighbours.…”

Section: Discussionmentioning

confidence: 99%

Two temperate super-Earths transiting a nearby late-type M dwarf

Delrez

Murray

Pozuelos

et al. 2022

A&A

View full text Add to dashboard Cite

Context. In the age of JWST, temperate terrestrial exoplanets transiting nearby late-type M dwarfs provide unique opportunities for characterising their atmospheres, as well as searching for biosignature gases. In this context, the benchmark TRAPPIST-1 planetary system has garnered the interest of a broad scientific community. Aims. We report here the discovery and validation of two temperate super-Earths transiting LP 890-9 (TOI-4306, SPECULOOS-2), a relatively low-activity nearby (32 pc) M6V star. The inner planet, LP 890-9 b, was first detected by TESS (and identified as TOI-4306.01) based on four sectors of data. Intensive photometric monitoring of the system with the SPECULOOS Southern Observatory then led to the discovery of a second outer transiting planet, LP 890-9 c (also identified as SPECULOOS-2 c), previously undetected by TESS. The orbital period of this second planet was later confirmed by MuSCAT3 follow-up observations. Methods. We first inferred the properties of the host star by analyzing its Lick/Kast optical and IRTF/SpeX near-infrared spectra, as well as its broadband spectral energy distribution, and Gaia parallax. We then derived the properties of the two planets by modelling multi-colour transit photometry from TESS, SPECULOOS-South, MuSCAT3, ExTrA, TRAPPIST-South, and SAINT-EX. Archival imaging, Gemini-South/Zorro high-resolution imaging, and Subaru/IRD radial velocities also support our planetary interpretation.Results. With a mass of 0.118 ± 0.002 M ⊙ , a radius of 0.1556 ± 0.0086 R ⊙ , and an effective temperature of 2850 ± 75 K, LP 890-9 is the secondcoolest star found to host planets, after TRAPPIST-1. The inner planet has an orbital period of 2.73 d, a radius of 1.320 +0.053 −0.027 R ⊕ , and receives an incident stellar flux of 4.09 ± 0.12 S ⊕ . The outer planet has a similar size of 1.367 +0.055 −0.039 R ⊕ and an orbital period of 8.46 d. With an incident stellar flux of 0.906 ± 0.026 S ⊕ , it is located within the conservative habitable zone, very close to its inner limit (runaway greenhouse). Although the masses of the two planets remain to be measured, we estimated their potential for atmospheric characterisation via transmission spectroscopy using a mass-radius relationship and found that, after the TRAPPIST-1 planets, LP 890-9 c is the second-most favourable habitable-zone terrestrial planet known so far (assuming for this comparison a similar atmosphere for all planets). Conclusions. The discovery of this remarkable system offers another rare opportunity to study temperate terrestrial planets around our smallest and coolest neighbours.

show abstract

Section: Discussionmentioning

confidence: 99%

Two temperate super-Earths transiting a nearby late-type M dwarf

Delrez

Murray

Pozuelos

et al. 2022

A&A

View full text Add to dashboard Cite

show abstract

“…Other studies have used GCMs, coupled with synthetic planetary spectrum generators, to simulate observations of transmission spectroscopy for transiting exoplanets (Arney et al 2017;Lines et al 2018;Boutle et al 2020;Suissa et al 2020;May et al 2021), enhancing the value of these models as an aid to interpreting observational data (Louden & Wheatley 2015;Brogi et al 2016). However, gaps in our understanding of the physics driving atmospheric phenomena on tidally locked planets, partly driven by differences in model structure and parameterizations (Sergeev et al 2020;Fauchez et al 2020;Sergeev et al 2021;Turbet et al 2021), may cause misinterpretations of atmospheric observations. Global 3D models of tidally locked planets exhibit an area of deep convection around the substellar point (Yang et al 2013;Kopparapu et al 2016;Hammond & Lewis 2021), leading to permanent cloud cover and heavy precipitation in this region (Yang et al 2013;Boutle et al 2017;Labonté & Merlis 2020;Sergeev et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Longitudinally Asymmetric Stratospheric Oscillation on a Tidally Locked Exoplanet

Cohen

Bollasina

Palmer

et al. 2022

ApJ

Self Cite

View full text Add to dashboard Cite

Using a three-dimensional general circulation model, we show that the atmospheric dynamics on a tidally locked Earth-like exoplanet, simulated with the planetary and orbital parameters of Proxima Centauri b, support a longitudinally asymmetric stratospheric wind oscillation (LASO), analogous to Earth’s quasi-biennial oscillation (QBO). In our simulations, the LASO has a vertical extent of 35–55 km, a period of 5–6.5 months, and a peak-to-peak wind speed amplitude of −70 to +130 m s−1 with a maximum at an altitude of 41 km. Unlike the QBO, the LASO displays longitudinal asymmetries related to the asymmetric thermal forcing of the planet and to interactions with the resulting stationary Rossby waves. The equatorial gravity wave sources driving the LASO are localized in the deep convection region at the substellar point and in a jet exit region near the western terminator, unlike the QBO, for which these sources are distributed uniformly around the planet. Longitudinally, the western terminator experiences the highest wind speeds and undergoes reversals earlier than other longitudes. The antistellar point only experiences a weak oscillation with a very brief, low-speed westward phase. The QBO on Earth is associated with fluctuations in the abundances of water vapor and trace gases such as ozone, which are also likely to occur on exoplanets if these gases are present. Strong fluctuations in temperature and the abundances of atmospheric species at the terminators will need to be considered when interpreting atmospheric observations of tidally locked exoplanets.

show abstract

“…Whether these parameterization schemes can be applied to exoplanet conditions is unknown, and different models employ different parameterization schemes. Recent model intercomparisons for tidally locked planets (Yang et al 2019b;Fauchez et al 2020;Sergeev et al 2021) have shown that there are large differences among the models in simulating the climate. Under a given stellar flux, a given greenhouse gas concentration, and the same boundary conditions (such as a uniform slab ocean at the surface), the simulated surface temperature differences in the global mean could be as large as 20-30 K. The underlying reasons are mainly due to cloud parameterization, the radiation calculation accuracy for water vapor, and differences in the relative humidity (which is associated with large-scale atmospheric circulation); the largest difference comes from clouds (Yang et al 2016(Yang et al , 2019b.…”

Section: Introductionmentioning

confidence: 99%

Idealized 2D Cloud-resolving Simulations for Tidally Locked Habitable Planets

Song

Yang

Luo

et al. 2022

ApJ

View full text Add to dashboard Cite

Cloud is critical for planetary climate and habitability, but it is also one of the most challenging aspects of studying planets in and beyond the solar system. Here we use a cloud-resolving model (CRM) with high resolution (2 km) in a 2D configuration to simulate the clouds and circulation on tidally locked aquaplanets. We find that the substellar area is covered by deep convective clouds, the nightside is dominated by low-level clouds, and the two are linked by a global-scale Walker circulation. We further find that uniform surface warming causes the substellar cloud width to decrease, but a reduction in the day–night surface temperature contrast or an increase in the longwave radiative cooling rate causes the substellar cloud width to increase. These relationships can be roughly interpreted in accordance with simple thermodynamic theories. Comparing the results between the CRM and the global 3D general circulation model (GCM), we find that they are qualitatively consistent, including the Walker circulation, the substellar clouds, and the responses of the substellar ascending area and strength to changes in the surface temperature or in its zonal contrast. But large quantitative differences exist, such as the magnitude of the cloud water path, the cloud width, and their responses to external forcings. These results increase our confidence in using GCMs to model exoplanetary climates, although large quantitative uncertainties are always likely to exist. Future work is required to use 3D CRMs with realistic radiative transfer and the Coriolis force to examine the clouds and climates of tidally locked planets.

show abstract

The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). Part II: Moist Cases -- The Two Waterworlds

Cited by 9 publications

References 84 publications

Two temperate super-Earths transiting a nearby late-type M dwarf

Two temperate super-Earths transiting a nearby late-type M dwarf

Longitudinally Asymmetric Stratospheric Oscillation on a Tidally Locked Exoplanet

Idealized 2D Cloud-resolving Simulations for Tidally Locked Habitable Planets

Contact Info

Product

Resources

About