The Astronomical Journal (Jan 2024)

High-resolution Dayside Spectroscopy of WASP-189 b: Detection of Iron during the GHOST/Gemini South System Verification Run

  • Emily K. Deibert,
  • Adam B. Langeveld,
  • Mitchell E. Young,
  • Laura Flagg,
  • Jake D. Turner,
  • Peter C. B. Smith,
  • Ernst J. W. de Mooij,
  • Ray Jayawardhana,
  • Kristin Chiboucas,
  • Roberto Gamen,
  • Christian R. Hayes,
  • Jeong-Eun Heo,
  • Miji Jeong,
  • Venu Kalari,
  • Eder Martioli,
  • Vinicius M. Placco,
  • Siyi Xu,
  • Ruben Diaz,
  • Manuel Gomez-Jimenez,
  • Carlos Quiroz,
  • Roque Ruiz-Carmona,
  • Chris Simpson,
  • Alan W. McConnachie,
  • John Pazder,
  • Gregory Burley,
  • Michael Ireland,
  • Fletcher Waller,
  • Trystyn A. M. Berg,
  • J. Gordon Robertson,
  • David O. Jones,
  • Kathleen Labrie,
  • Susan Ridgway,
  • Joanna Thomas-Osip

DOI
https://doi.org/10.3847/1538-3881/ad643f
Journal volume & issue
Vol. 168, no. 4
p. 148

Abstract

Read online

With high equilibrium temperatures and tidally locked rotation, ultra-hot Jupiters (UHJs) are unique laboratories within which to probe extreme atmospheric physics and chemistry. In this paper, we present high-resolution dayside spectroscopy of the UHJ WASP-189 b obtained with the new Gemini High-resolution Optical SpecTrograph (GHOST) at the Gemini South Observatory. The observations, which cover 3 hr of post-eclipse orbital phases, were obtained during the instrument’s System Verification run. We detect the planet’s atmosphere via the Doppler cross-correlation technique, and recover a detection of neutral iron in the planet’s dayside atmosphere at a significance of 7.5 σ in the red arm of the data, verifying the presence of a thermal inversion. We also investigate the presence of other species in the atmosphere and discuss the implications of model injection/recovery tests. These results represent the first atmospheric characterization of an exoplanet with GHOST’s high-resolution mode, and demonstrate the potential of this new instrument in detecting and studying ultra-hot exoplanet atmospheres.

Keywords