High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood

TL;DR

This study investigates the high-energy irradiation and mass loss rates of nearby hot Jupiters, using X-ray observations and Lyman alpha estimates to understand atmospheric escape and its impact on planetary evolution.

Contribution

It provides new measurements of high-energy irradiation and mass loss rates for nine hot Jupiters near the Sun, identifying candidates for Lyman alpha transit spectroscopy.

Findings

WASP-80 b, WASP-77 b, and WASP-43 b have the highest mass loss rates.

Seven out of nine targets are suitable for Lyman alpha transit spectroscopy.

Weak evidence for angular momentum transfer in some binary systems.

Abstract

Giant gas planets in close proximity to their host stars experience strong irradiation. In extreme cases photoevaporation causes a transonic, planetary wind and the persistent mass loss can possibly affect the planetary evolution. We have identified nine hot Jupiter systems in the vicinity of the Sun, in which expanded planetary atmospheres should be detectable through Lyman alpha transit spectroscopy according to predictions. We use X-ray observations with Chandra and XMM-Newton of seven of these targets to derive the high-energy irradiation level of the planetary atmospheres and the resulting mass loss rates. We further derive improved Lyman alpha luminosity estimates for the host stars including interstellar absorption. According to our estimates WASP-80 b, WASP-77 b, and WASP-43 b experience the strongest mass loss rates, exceeding the mass loss rate of HD 209458 b, where an expanded atmosphere has been confirmed. Furthermore, seven out of nine targets might be amenable to Lyman alpha transit spectroscopy. Finally, we check the possibility of angular momentum transfer from the hot Jupiters to the host stars in the three binary systems among our sample, but find only weak indications for increased stellar rotation periods of WASP-77 and HAT-P-20.