Evolution of helium triplet transits of close-in gas giants orbiting K-dwarfs

Abstract

Atmospheric escape in exoplanets has traditionally been observed using hydrogen Lyman-$\alpha$ and H-$\alpha$ transmission spectroscopy, but more recent detections have utilised the metastable helium triplet at 1083 nm. Since this feature is accessible from the ground, it offers new possibilities for studying atmospheric escape. Our goal is to understand how the observability of escaping helium evolves during the lifetime of a highly irradiated gas giant. We extend our previous work on 1-D self-consistent hydrodynamic escape from hydrogen-only atmospheres as a function of planetary evolution to the first evolution-focused study of escaping hydrogen-helium atmospheres. Additionally, using these novel models we perform helium triplet transmission spectroscopy. We adapt our previous hydrodynamic escape model to now account for both hydrogen and helium heating and cooling processes and simultaneously solve for the population of helium in the triplet state. To account for the planetary evolution, we utilise evolving predictions of planetary radii for a close-in 0.3$M_{\mathrm{Jup}}$ gas giant and its received stellar flux in X-ray, hard and soft EUV, and mid-UV wavelength bins assuming a K dwarf stellar host. We find that the helium triplet signature diminishes with evolution. Our models suggest that young ($\lesssim 150$~Myr), close-in gas giants ($\sim 1$ to $2R_{\mathrm{Jup}}$) should produce helium 1083 nm transit absorptions of $\sim 4\%$ or $\sim 7\%$, for a slow or fast-rotating K dwarf, respectively, assuming a 2$\%$ helium abundance.

20 pages, 13 figures, 4 tables; published in MNRAS; Table 2 is now updated to correct an error in the radiative decay rate from the He(2${}^1$s) state and additional minor typographical errors, as now described in Appendix D

References in corpus (43)

• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• Atmospheric Escape from Hot Jupiters
• Stellar magnetism: empirical trends with age and rotation
• The active lives of stars: a complete description of rotation and XUV evolution of F, G, K, and M dwarfs
• High-resolution confirmation of an extended helium atmosphere around WASP-107b
• Heating efficiency in hydrogen-dominated upper atmospheres
• Confirmation of WASP-107b's extended Helium atmosphere with Keck II/NIRSPEC
• Limits on the Spin-Orbit Angle and Atmospheric Escape for the 22 Myr-old Planet AU Mic b
• The GAPS programme at TNG XXII. The GIARPS view of the extended helium atmosphere of HD189733 b accounting for stellar activity
• Detection of Atmospheric Escape from Four Young Mini Neptunes
• p-winds: an open-source Python code to model planetary outflows and upper atmospheres
• Detection of Ongoing Mass Loss from HD 63433c, a Young Mini Neptune
• Water and an escaping helium tail detected in the hazy and methane-depleted atmosphere of HAT-P-18b from JWST NIRISS/SOSS
• Stellar Wind Confinement of Evaporating Exoplanet Atmospheres and its Signatures in 1083 nm Observations
• No escaping helium from 55 Cnc e
• The post-transit tail of WASP-107b observed at 10830A
• Coupling thermal evolution of planets and hydrodynamic atmospheric escape in MESA
• Irradiation-driven escape of primordial planetary atmospheres I. The ATES photoionization hydrodynamics code
• TPCI: The PLUTO-CLOUDY Interface
• Effects of the stellar wind on the Ly-alpha transit of close-in planets
• Modelling the He I triplet absorption at 10830 Angstroms in the atmospheres of HD 189733 b and GJ 3470 b
• Metastable Helium Absorptions with 3D Hydrodynamics and Self-Consistent Photochemistry I: WASP-69b, Dimensionality, XUV Flux Level, Spectral Types, and Flares
• Metastable Helium Absorptions with 3D Hydrodynamics and Self-Consistent Photochemistry II: WASP-107b, Stellar Wind, Radiation Pressure, and Shear Instability
• The dichotomy of atmospheric escape in AU Mic b
• The impact of intrinsic magnetic field on the absorption signatures of elements probing the upper atmosphere of HD209458b
• The GAPS Programme at TNG. XXXII. The revealing non-detection of metastable HeI in the atmosphere of the hot Jupiter WASP-80b
• Constraining planetary mass-loss rates by simulating Parker wind profiles with Cloudy
• The mass-radius relation of intermediate-mass planets outlined by hydrodynamic escape and thermal evolution
• How does the mass and activity history of the host star affect the population of low-mass planets?
• Helium absorption in exoplanet atmospheres is connected to stellar coronal abundances
• Global 3D simulation of the upper atmosphere of HD189733b and absorption in metastable HeI and Lyα lines
• Universal Scaling Laws for Solar and Stellar Atmospheric Heating
• Modeling H$\alpha$ and He 10830 transmission spectrum of WASP-52b
• Zodiacal Exoplanets in Time (ZEIT) XIII: Planet Orbits and Atmospheres in the V1298 Tau System, a Keystone in Studies of Early Planetary Evolution
• Simulation of 10830 Å absorption with a 3D hydrodynamic model reveals the solar He abundance in upper atmosphere of WASP-107b
• Global 3D hydrodynamic modeling of absorption in Lyα and He 10830 A lines at transits of GJ3470b
• Planet(esimal)s Around Stars with TESS (PAST) III: A Search for Triplet He I in the Atmospheres of Two 200 Myr-old Planets
• HAZMAT. VIII. A Spectroscopic Analysis of the Ultraviolet Evolution of K Stars: Additional Evidence for K Dwarf Rotational Stalling in the First Gigayear
• Revisiting Kepler-444. II. Rotational, orbital and high-energy fluxes evolution of the system
• Hydrodynamic atmospheric escape in HD 189733 b: Signatures of carbon and hydrogen measured with the Hubble Space Telescope
• The key impact of the host star's rotational history on the evolution of TOI-849b
• Observations of planetary winds and outflows

Cited by in corpus (7)

• The MOPYS project: A survey of 70 planets in search of extended He I and H atmospheres. No evidence of enhanced evaporation in young planets
• The open-source sunbather code: modeling escaping planetary atmospheres and their transit spectra
• Helium in Exoplanet Exospheres: Orbital and Stellar Influences
• Using the helium triplet as a tracer of the physics of giant planet outflows
• Helium escape signatures are generally strongest during younger ages but this age dependence is lost in the diversity of observed exoplanets
• Modelling helium in exoplanet atmospheres. A revised network with photoelectron-driven processes
• The effects of stellar activity cycles on planetary atmospheric escape and the HeI 1083nm transit signature