Issue |
A&A
Volume 632, December 2019
|
|
---|---|---|
Article Number | A69 | |
Number of page(s) | 12 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/201936396 | |
Published online | 05 December 2019 |
Ionized calcium in the atmospheres of two ultra-hot exoplanets WASP-33b and KELT-9b★
1
Institut für Astrophysik, Georg-August-Universität,
Friedrich-Hund-Platz 1,
37077
Göttingen,
Germany
e-mail: fei.yan@uni-goettingen.de
2
Instituto de Astrofísica de Canarias (IAC),
Calle Vía Lactea s/n,
38200
La Laguna,
Tenerife,
Spain
3
Departamento de Astrofísica, Universidad de La Laguna,
38026
La Laguna,
Tenerife,
Spain
4
Max-Planck-Institut für Astronomie,
Königstuhl 17,
69117
Heidelberg,
Germany
5
Leiden Observatory, Leiden University,
Postbus 9513,
2300 RA
Leiden,
The Netherlands
6
Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences,
Nanjing
210033,
PR China
7
Institut de Ciències de l’Espai (CSIC-IEEC),
Campus UAB, c/ de Can Magrans s/n,
08193
Bellaterra,
Barcelona,
Spain
8
Institut d’Estudis Espacials de Catalunya (IEEC),
08034
Barcelona,
Spain
9
Landessternwarte, Zentrum für Astronomie der Universität Heidelberg,
Königstuhl 12,
69117
Heidelberg,
Germany
10
Centro de Astrobiología (CSIC-INTA), ESAC,
Camino bajo del castillo s/n,
28692
Villanueva de la Cañada,
Madrid,
Spain
11
Instituto de Astrofísica de Andalucía (IAA-CSIC),
Glorieta de la Astronomía s/n,
18008
Granada,
Spain
12
Centro Astronónomico Hispano-Alemán (CSIC-MPG), Observatorio Astronónomico de Calar Alto,
Sierra de los Filabres,
04550
Gérgal,
Almería,
Spain
13
Hamburger Sternwarte, Universität Hamburg,
Gojenbergsweg 112,
21029
Hamburg,
Germany
14
Departamento de Física de la Tierra y Astrofísica and IPARCOS-UCM (Intituto de Física de Partículas y del Cosmos de la UCM), Facultad de Ciencias Físicas, Universidad Complutense de Madrid,
28040
Madrid,
Spain
Received:
28
July
2019
Accepted:
30
October
2019
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&K doublet and the near-infrared triplet, and measure their line profiles. The Ca II H&K lines have an average line depth of 2.02 ± 0.17% (effective radius of 1.56 Rp) for WASP-33b and an average line depth of 0.78 ± 0.04% (effective radius of 1.47 Rp) 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.
Key words: planets and satellites: atmospheres / techniques: spectroscopic / planets and satellites: individual: WASP-33b / planets and satellites: individual: KELT-9b
The reduced transmission spectrum is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/632/A69
© ESO 2019
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