A SEARCH for Hα ABSORPTION AROUND KELT-3 b and GJ 436 b

P. Wilson Cauley, Seth Redfield, Adam G. Jensen

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Observations of extended atmospheres around hot planets have generated exciting results concerning the dynamics of escaping planetary material. The configuration of the escaping planetary gas can result in asymmetric transit features, producing both pre- and post-transit absorption in specific atomic transitions. Measuring the velocity and strength of the absorption can provide constraints on the mass loss mechanism, and potentially clues to the interactions between the planet and the host star. Here we present a search for Hα absorption in the circumplanetary environments of the hot planets KELT-3 b and GJ 436 b. We find no evidence for absorption around either planet at any point during the two separate transit epochs for which each system was observed. We provide upper limits on the radial extent and density of the excited hydrogen atmospheres around both planets. The null detection for GJ 436 b contrasts with the strong Lyα absorption measured for the same system, suggesting that the large cloud of neutral hydrogen is almost entirely in the ground state. The only confirmed exoplanetary Hα absorption to date has been made around the active star HD 189733 b. KELT-3 and GJ 436 are less active than HD 189733, hinting that exoplanet atmospheres exposed to EUV photons from active stars are better suited for detection of Hα absorption.

Original languageEnglish (US)
Article number81
JournalAstronomical Journal
Volume153
Issue number2
DOIs
StatePublished - Feb 2017

Keywords

  • planets and satellites: atmospheres
  • planets and satellites: individual (GJ 436 b, KELT-3 b)
  • techniques: spectroscopic

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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