title: Detection of carbon monoxide and water absorption lines in an exoplanet atmosphere.
abstract: Determining the atmospheric structure and chemical composition of an exoplanet remains a formidable goal. Fortunately, advancements in the study of exoplanets and their atmospheres have come in the form of direct imaging--spatially resolving the planet from its parent star--which enables high-resolution spectroscopy of self-luminous planets in jovian-like orbits. Here, we present a spectrum with numerous, well-resolved molecular lines from both water and carbon monoxide from a massive planet orbiting less than 40 astronomical units from the star HR 8799. These data reveal the planet's chemical composition, atmospheric structure, and surface gravity, confirming that it is indeed a young planet. The spectral lines suggest an atmospheric carbon-to-oxygen ratio that is greater than that of the host star, providing hints about the planet's formation.
authors.affiliation: Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada. konopacky@di.utoronto.ca
authors.forename: Quinn M
authors.initials: QM
authors.lastname: Konopacky
authors.forename: Travis S
authors.initials: TS
authors.lastname: Barman
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Macintosh
authors.forename: Christian
authors.initials: C
authors.lastname: Marois
mesh_terms: D001272:Atmosphere; D002248:Carbon Monoxide; D019419:Evolution, Planetary; D005118:Extraterrestrial Environment; D006112:Gravitation; D016083:Planets; D013057:Spectrum Analysis; D014867:Water
chemical_list: D014867:Water; D002248:Carbon Monoxide