Detection of Ionized Calcium in the Atmosphere of the Ultra-hot Jupiter KELT-9b
AuthorTurner, Jake D.
de Mooij, Ernst J. W.
Young, Mitchell E.
Lothringer, Joshua D.
AffiliationUniv Arizona, Lunar & Planetary Lab
Extrasolar gas giants
Exoplanet atmospheric composition
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationTurner, J. D., de Mooij, E. J., Jayawardhana, R., Young, M. E., Fossati, L., Koskinen, T., ... & Karjalainen, M. (2020). Detection of Ionized Calcium in the Atmosphere of the Ultra-hot Jupiter KELT-9b. The Astrophysical Journal Letters, 888(1), L13.
JournalASTROPHYSICAL JOURNAL LETTERS
RightsCopyright © 2020. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractWith a dayside temperature in excess of 4500 K, comparable to a mid-K-type star, KELT-9b is the hottest planet known. Its extreme temperature makes KELT-9b a particularly interesting test bed for investigating the nature and diversity of gas giant planets. We observed the transit of KELT-9b at high spectral resolution (R similar to 94,600) with the CARMENES instrument on the Calar Alto 3.5 m telescope. Using these data, we detect for the first time ionized calcium (Ca ii triplet) absorption in the atmosphere of KELT-9b; this is the second time that Ca ii has been observed in a hot Jupiter. Our observations also reveal prominent H alpha absorption, confirming the presence of an extended hydrogen envelope around KELT-9b. We compare our detections with an atmospheric model and find that all four lines form between atmospheric temperatures of 6100 and 8000 K and that the Ca ii lines form at pressures between 50 and 100 nbar while the H alpha line forms at a lower pressure (similar to 10 nbar), higher up in the atmosphere. The altitude that the core of H alpha line forms is found to be similar to 1.4 R-p, well within the planetary Roche lobe (similar to 1.9 R-p). Therefore, rather than probing the escaping upper atmosphere directly, the H alpha line and the other observed Balmer and metal lines serve as atmospheric thermometers enabling us to probe the planet's temperature profile, thus the energy budget.
VersionFinal published version
SponsorsGerman Max-Planck Gesellschaft (MPG); Spanish Consejo Superior de Investigaciones Cientificas (CSIC) Consejo Superior de Investigaciones Cientificas (CSIC); European Union through FEDER/ERF [FICTS-2011-02]; CARMENES Consortium; Spanish Ministry of Science Spanish Government; German Science Foundation (DFG) German Research Foundation (DFG); Klaus Tschira Stiftung; states of Baden-Wurttemberg and Niedersachsen; Junta de Andalucia Junta de Andalucia; NIST's Standard Reference Data Program (SRDP); NIST's Systems Integration for Manufacturing Applications (SIMA) Program