Global 3D hydrodynamic modeling of absorption in Lyα and He 10830 A lines at transits of GJ3470b

Шайхисламов, И. Ф.; Khodachenko, M. L.; Lämmer, H.; Berezutsky, A. G.; Мирошниченко, И. Б.; Руменских, М. С.

doi:10.1093/mnras/staa2367

Cited by 21 publications

(13 citation statements)

References 29 publications

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“…Lanza 2010;Poppenhaeger & Wolk 2014;Mancini et al 2017). Fossati et al (2021) modeled the impact of stellar wind on WASP-80b using a three-dimensional hydrodynamical model (Shaikhislamov et al 2021;, and showed that it does not suppress the helium signal enough to match their non-detection. They modeled stellar mass-loss rates up to ∼ 10 Ṁ , but at early times the wind can be even stronger.…”

Section: Low Mass-loss Rates For Wasp-80b and Wasp-52bmentioning

confidence: 99%

“…Fossati et al (2021) modeled the composition of WASP-80b's outflow and showed that helium depletion (with n He /n H ∼ 0.01) might plausibly explain these data. Previous studies of HD 209458b, HD 189733b, and GJ 3470b have sought to quantify the fractional abundances of hydrogen and helium in planetary outflows by comparing the magnitude of absorption measured in both the Lyman-α and metastable helium lines to Parker wind models (Lampón et al 2020(Lampón et al , 2021a or 3D hydrodynamical models (Shaikhislamov et al 2021). However, Lyman-α is a poor tracer for the density distribution in the planetary thermosphere, typically probing above the exobase at high velocities (e.g.…”

Section: Low Mass-loss Rates For Wasp-80b and Wasp-52bmentioning

confidence: 99%

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The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

Vissapragada¹,

Knutson²,

Greklek-McKeon³

et al. 2022

Preprint

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Transit surveys indicate that there is a deficit of Neptune-sized planets on close-in orbits. If this "Neptune desert" is entirely cleared out by atmospheric mass loss, then planets at its upper edge should only be marginally stable against photoevaporation, exhibiting strong outflow signatures in tracers like the metastable helium triplet. We test this hypothesis by carrying out a 12-night photometric survey of the metastable helium feature with Palomar/WIRC, targeting seven gas-giant planets orbiting K-type host stars. Eight nights of data are analyzed here for the first time along with reanalyses of four previously-published datasets. We strongly detect helium absorption signals for WASP-69b, HAT-P-18b, and HAT-P-26b; tentatively detect signals for WASP-52b and NGTS-5b; and do not detect signals for WASP-177b and WASP-80b. We interpret these measured excess absorption signals using grids of isothermal Parker wind models to derive mass-loss rates, which are typically around 10 10 − 10 11 g s −1 . Our empirically constrained mass-loss rates are in good agreement with predictions from the 1D hydrodynamical outflow code ATES for all planets except WASP-52b and WASP-80b, where our data suggest that the outflows are much smaller than predicted. Excluding these two planets, the outflows for the rest of the sample are consistent with a mean energy-limited outflow efficiency of ε = 0.41 +0.16 −0.13 . Even when we make the relatively conservative assumption that gas-giant planets experience energy-limited outflows at this efficiency for their entire lives, photoevaporation would still be too inefficient to carve the upper boundary of the Neptune desert. We conclude that this feature of the exoplanet population is a pristine tracer of giant planet formation and migration mechanisms.

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Section: Low Mass-loss Rates For Wasp-80b and Wasp-52bmentioning

confidence: 99%

Section: Low Mass-loss Rates For Wasp-80b and Wasp-52bmentioning

confidence: 99%

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

Vissapragada¹,

Knutson²,

Greklek-McKeon³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…They argued that a high H/He number ratio larger than 90/10 is required to fit the observation. Besides, 3D simulations were also performed to explain the He 10830 absorption in WASP-107b, GJ 3470b, and WASP-69b (Wang & Dai 2021a;Khodachenko et al 2021a;Wang & Dai 2021b;Khodachenko et al 2021b;Shaikhislamov et al 2021;Rumenskikh et al 2022). A 3D simulation can reproduce the asymmetry features in the transit light curves and transmission spectra well but is time-consuming in parameter exploration.…”

Section: Introductionmentioning

confidence: 99%

Modeling the Hα and He 10830 Transmission Spectrum of WASP-52b

Yan

Seon

Guo

et al. 2022

ApJ

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Escaping atmosphere has been detected by the excess absorption of Lyα, Hα and He triplet (λ10830) lines. Simultaneously modeling the absorption of the Hα and He λ10830 lines can provide useful constraints about the exoplanetary atmosphere. In this paper, we use a hydrodynamic model combined with a non−local thermodynamic model and a new Monte Carlo simulation model to obtain the H(2) and He(23 S) populations. The Monte Carlo simulations of Lyα radiative transfer are performed with assumptions of a spherical stellar Lyα radiation and a spherical planetary atmosphere, for the first time, to calculate the Lyα mean intensity distribution inside the planetary atmosphere, necessary in estimating the H(2) population. We model the transmission spectra of the Hα and He λ10830 lines simultaneously in hot Jupiter WASP-52b. We find that models with many different H/He ratios can reproduce the Hα observations well if the host star has (1) a high X-ray and extreme-ultraviolet (XUV) flux (F XUV) and a relatively low X-ray fraction in XUV radiation (β m ) or (2) a low F XUV and a high β m . The simulations of the He λ10830 triplet suggest that a high H/He ratio (∼98/2) is required to fit the observation. The models that fit both lines well confine F XUV to be about 0.5 times the fiducial value and β m to have a value around 0.3. The models also suggest that hydrogen and helium originate from the escaping atmosphere, and the mass-loss rate is about 2.8 × 1011 g s−1.

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“…However, similar tools can be used to predict and interpret observations at 1083 nm. The first examples of that approach, focused on modeling individual planets with reported helium detections, have recently been presented by Khodachenko et al (2021); Shaikhislamov et al (2021); Wang & Dai (2020a,b).…”

Section: Introductionmentioning

confidence: 99%

Stellar Wind Confinement of Evaporating Exoplanet Atmospheres and its Signatures in 1083 nm Observations

MacLeod,

Oklopčić

2021

Preprint

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Atmospheric escape from close-in exoplanets is thought to be crucial in shaping observed planetary populations. Recently, significant progress has been made in observing this process in action through excess absorption in transit spectra and narrowband light curves. We present a 3D hydrodynamic simulation and radiative transfer post-processing method for modeling the interacting flows of escaping planetary atmosphere and stellar winds. We focus on synthetic transmission spectra of the helium 1083 nm line, and discuss a planetary outflow of fixed mass-loss rate that interacts with stellar winds of varying order of magnitude. The morphology of these outflows in differing stellar wind environments changes dramatically, from torii that completely encircle the star when the ram pressure of the stellar wind is low, to cometary tails of planetary outflow when the stellar wind ram pressure is high. Our results demonstrate that this interaction leaves important traces on line kinematics and spectral phase curves in the helium 1083 nm triplet. In particular, the confinement of outflows through wind-wind collisions leads to absorption that extends in phase and time well beyond the optical transit. We further demonstrate that these differences are reflected in light curves of He 1083 nm equivalent width as a function of transit phase. Our results suggest that combining high-resolution spectroscopy with narrowband photometry offers a path to observationally probe how stellar wind environments shape exoplanetary atmosphere escape.

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Global 3D hydrodynamic modeling of absorption in Lyα and He 10830 A lines at transits of GJ3470b

Cited by 21 publications

References 29 publications

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

Modeling the Hα and He 10830 Transmission Spectrum of WASP-52b

Stellar Wind Confinement of Evaporating Exoplanet Atmospheres and its Signatures in 1083 nm Observations

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