High Energy Exoplanet Transits

Joe Llama, Evgenya Shkolnik

Research output: Contribution to journalArticle

Abstract

X-ray and ultraviolet transits of exoplanets allow us to probe the atmospheres of these worlds. High energy transits have been shown to be deeper but also more variable than in the optical. By simulating exoplanet transits using high-energy observations of the Sun, we can test the limits of our ability to accurately measure the properties of these planets in the presence of stellar activity. We use both disk-resolved images of the Solar disk spanning soft X-rays, the ultraviolet, and the optical and also disk-integrated Sun-as-a-star observations of the Lyα irradiance to simulate transits over a wide wavelength range. We find that for stars with activity levels similar to the Sun, the planet-to-star radius ratio can be overestimated by up to 50% if the planet occults an active region at high energies. We also compare our simulations to high energy transits of WASP-12b, HD 189733, 55 Cnc b, and GJ 436b.

Original languageEnglish (US)
Pages (from-to)356-362
Number of pages7
JournalProceedings of the International Astronomical Union
Volume12
DOIs
StatePublished - 2016

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extrasolar planets
transit
sun
planet
planets
energy
stars
stellar activity
optical disks
irradiance
probe
wavelength
x rays
atmosphere
atmospheres
radii
probes
simulation
wavelengths

Keywords

  • (stars:) planetary systems
  • stars: activity
  • stars: spots
  • Sun: activity

ASJC Scopus subject areas

  • Astronomy and Astrophysics

Cite this

High Energy Exoplanet Transits. / Llama, Joe; Shkolnik, Evgenya.

In: Proceedings of the International Astronomical Union, Vol. 12, 2016, p. 356-362.

Research output: Contribution to journalArticle

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