Ionized calcium in the atmospheres of two ultra-hot exoplanets WASP-33b and KELT-9b

DOI: 
10.1051/0004-6361/201936396
Publication date: 
01/12/2019
Main author: 
Yan, F.
IAA authors: 
Amado, P. J.;Bauer, F. F.;Lara, L. M.;López-Puertas, M.;Sánchez-López, A.
Authors: 
Yan, F.;Casasayas-Barris, N.;Molaverdikhani, K.;Alonso-Floriano, F. J.;Reiners, A.;Pallé, E.;Henning, Th.;Mollière, P.;Chen, G.;Nortmann, L.;Snellen, I. A. G.;Ribas, I.;Quirrenbach, A.;Caballero, J. A.;Amado, P. J.;Azzaro, M.;Bauer, F. F.;Cortés Contreras, M.;Czesla, S.;Khalafinejad, S.;Lara, L. M.;López-Puertas, M.;Montes, D.;Nagel, E.;Oshagh, M.;Sánchez-López, A.;Stangret, M.;Zechmeister, M.
Journal: 
Astronomy and Astrophysics
Refereed: 
Yes
Publication type: 
Article
Volume: 
632
Pages: 
A69
Abstract: 
Ultra-hot Jupiters are emerging as a new class of exoplanets. Studying their chemical compositions and temperature structures will improve our understanding of their mass loss rate as well as their formation and evolution. We present the detection of ionized calcium in the two hottest giant exoplanets - KELT-9b and WASP-33b. By using transit datasets from CARMENES and HARPS-N observations, we achieved high-confidence-level detections of Ca II using the cross-correlation method. We further obtain the transmission spectra around the individual lines of the Ca II H&amp;K doublet and the near-infrared triplet, and measure their line profiles. The Ca II H&amp;K lines have an average line depth of 2.02 ± 0.17% (effective radius of 1.56 R<SUB>p</SUB>) for WASP-33b and an average line depth of 0.78 ± 0.04% (effective radius of 1.47 R<SUB>p</SUB>) for KELT-9b, which indicates that the absorptions are from very high upper-atmosphere layers close to the planetary Roche lobes. The observed Ca II lines are significantly deeper than the predicted values from the hydrostatic models. Such a discrepancy is probably a result of hydrodynamic outflow that transports a significant amount of Ca II into the upper atmosphere. The prominent Ca II detection with the lack of significant Ca I detection implies that calcium is mostly ionized in the upper atmospheres of the two planets. <P />The reduced transmission spectrum is only available at the CDS via anonymous ftp to <A href='http://cdsarc.u-strasbg.fr'>http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href='http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/632/A69'>http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/632/A69</A>
Database: 
ADS
SCOPUS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079752594&doi=10.1051%2f0004-6361%2f201936396&partnerID=40&md5=6f76f5493c0368880cabde0fe70d933f
ADS Bibcode: 
2019A&A...632A..69Y
Keywords: 
planets and satellites: atmospheres;techniques: spectroscopic;planets and satellites: individual: WASP-33b;planets and satellites: individual: KELT-9b