X-ray Studies of Planetary Systems: An Astro2010 Decadal Survey White Paper

TL;DR

X-ray astronomy offers valuable insights into planetary systems by studying stellar activity, planetary atmospheres, and space weather, with upcoming observatories enabling new research in these areas.

Contribution

This paper highlights six innovative studies enabled by the planned International X-ray Observatory to advance planetary science understanding.

Findings

X-ray irradiation impacts protoplanetary disk turbulence.

Charge-exchange X-ray emission reveals planetary and cometary processes.

Stellar magnetic activity influences planetary atmosphere evaporation.

Abstract

While it may seem counterintuitive that X-ray astronomy should give any insights into low-temperature planetary systems, planets orbit stars whose magnetized surfaces divert a small fraction of the stellar energy into high energy products: coronal UV and X-rays, flare X-rays and energetic particles, and a high-velocity stellar wind. In our Solar System, X-ray emission gives unique insights into the solar activity, planetary atmospheres, cometary comae, charge exchange physics, and space weather across the Solar System. The stellar activity of young stars is greatly elevated and can substantially affect protoplanetary disks and planet formation processes. We highlight six studies achievable with the planned International X-ray Observatory which address in unique ways issues in planetary sciences: probing X-ray irradiation of protoplanetary disks with the iron fluorescent line and its effects on disk turbulence; study the complex charge-exchange X-ray emission from Jupiter and the Martian exosphere; elucidate charge-exchange processes in cometary comae; understanding heliospheric charge-exchange emission and the interpretation of the soft X-ray background; and examining the magnetic activity of planet-hosting stars and its evaporation of planetary atmospheres.