PROSPECTS FOR CHARACTERIZING THE ATMOSPHERE OF PROXIMA CENTAURI b

Kreidberg, Laura; Loeb, Abraham

doi:10.3847/2041-8205/832/1/l12

Cited by 98 publications

(95 citation statements)

References 52 publications

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“…In reality, we wish to note there are many possibilities for the atmospheric composition of PCb, provided that it even exists (Ribas et al 2016;Turbet et al 2016;Goldblatt 2016). A clearer picture regarding the existence and composition of the atmosphere may emerge via the JWST (Kreidberg & Loeb 2016). …”

Section: Physical Model and Computational Methodologymentioning

confidence: 99%

Is Proxima Centauri b Habitable? A Study of Atmospheric Loss

Dong

Lingam

et al. 2017

ApJL

184

192

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We address the important question of whether the newly discovered exoplanet, Proxima Centauri b (PCb), is capable of retaining an atmosphere over long periods of time. This is done by adapting a sophisticated multi-species MHD model originally developed for Venus and Mars, and computing the ion escape losses from PCb. The results suggest that the ion escape rates are about two orders of magnitude higher than the terrestrial planets of our Solar system if PCb is unmagnetized. In contrast, if the planet does have an intrinsic dipole magnetic field, the rates are lowered for certain values of the stellar wind dynamic pressure, but they are still higher than the observed values for our Solar system's terrestrial planets. These results must be interpreted with due caution, since most of the relevant parameters for PCb remain partly or wholly unknown.

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Section: Physical Model and Computational Methodologymentioning

confidence: 99%

Is Proxima Centauri b Habitable? A Study of Atmospheric Loss

Dong

Lingam

et al. 2017

ApJL

184

192

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“…It has been pointed out that it is sufficiently close to Earth as to be directly observable by the next generation of space telescopes such as WFIRST and JWST, in addition to planned 30-meter class ground-based telescopes Kreidberg & Loeb 2016).…”

Section: Introductionmentioning

confidence: 99%

THE SPACE WEATHER OF PROXIMA CENTAURI b

Garraffo

Drake

Cohen

2016

ApJL

159

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A planet orbiting in the "habitable zone" of our closest neighboring star, Proxima Centauri, has recently been discovered, and the next natural question is whether or not Proxima b is"habitable". Stellar winds are likely a source of atmospheric erosion that could be particularly severe in the case of M dwarf habitable zone planets that reside close to their parent star. Here we study the stellar wind conditions that Proxima b experiences over its orbit. We construct 3-D MHD models of the wind and magnetic field around Proxima Centauri using a surface magnetic field map for a star of the same spectral type and scaled to match the observed ∼ 600 G surface magnetic field strength of Proxima. We examine the wind conditions and dynamic pressure over different plausible orbits that sample the constrained parameters of the orbit of Proxima b. For all the parameter space explored, the planet is subject to stellar wind pressures of more than 2000 times those experienced by Earth from the solar wind. During an orbit, Proxima b is also subject to pressure changes of 1 to 3 orders of magnitude on timescales of a day. Its magnetopause standoff distance consequently undergoes sudden and periodic changes by a factor of 2 to 5. Proxima b will traverse the interplanetary current sheet twice each orbit, and likely crosses into regions of subsonic wind quite frequently. These effects should be taken into account in any physically realistic assessment or prediction of its atmospheric reservoir, characteristics and loss.

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“…For the thermal model, we used the simple physical model described in Kreidberg & Loeb (2016), as implemented in spiderman. The free parameters of this model are the planetary Bond albedo, and a day-to-night heat redistribution parameter, while the incident flux on the planet (required by the model) is obtained from the stellar and planetary parameters from the previous sections.…”

Section: Secondary Eclipse and Phase Curve Of K2-141bmentioning

confidence: 99%

An Ultra-short Period Rocky Super-Earth with a Secondary Eclipse and a Neptune-like Companion around K2-141

Malavolta

Mayo

Louden

et al. 2018

Self Cite

147

119

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Ultra-short period (USP) planets are a class of low-mass planets with periods shorter than one day. Their origin is still unknown, with photo-evaporation of mini-Neptunes and in situ formation being the most credited hypotheses. Formation scenarios differ radically in the predicted composition of USP planets, and it is therefore extremely important to increase the still limited sample of USP planets with precise and accurate mass and density measurements. We report here the characterization of a USP planet with a period of 0.28 days around K2-141 (EPIC 246393474), and the validation of an outer planet with a period of 7.7 days in a grazing transit configuration. We derived the radii of the planets from the K2 light curve and used high-precision radial velocities gathered with the HARPS-N spectrograph for mass measurements. For K2-141b, we thus inferred a radius of 1.51±0.05R Å and a mass of 5.08±0.41M Å , consistent with a rocky composition and lack of a thick atmosphere. K2-141c is likely a Neptune-like planet, although due to the grazing transits and the non-detection in the RV data set, we were not able to put a strong constraint on its density. We also report the detection of secondary eclipses and phase curve variations for K2-141b. The phase variation can be modeled either by a planet with a geometric albedo of 0.30±0.06 in the Kepler bandpass, or by thermal emission from the surface of the planet at ∼3000 K. Only follow-up observations at longer wavelengths will allow us to distinguish between these two scenarios.

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PROSPECTS FOR CHARACTERIZING THE ATMOSPHERE OF PROXIMA CENTAURI b

Cited by 98 publications

References 52 publications

Is Proxima Centauri b Habitable? A Study of Atmospheric Loss

Is Proxima Centauri b Habitable? A Study of Atmospheric Loss

THE SPACE WEATHER OF PROXIMA CENTAURI b

An Ultra-short Period Rocky Super-Earth with a Secondary Eclipse and a Neptune-like Companion around K2-141

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