Issue |
A&A
Volume 621, January 2019
|
|
---|---|---|
Article Number | A74 | |
Number of page(s) | 11 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/201834339 | |
Published online | 10 January 2019 |
Multiple water band detections in the CARMENES near-infrared transmission spectrum of HD 189733 b
1
Leiden Observatory, Leiden University,
Postbus 9513,
2300 RA
Leiden,
The Netherlands
e-mail: alonso@strw.leidenuniv.nl
2
Instituto de Astrofísica de Andalucía (IAA-CSIC),
Glorieta de la Astronomía s/n,
18008
Granada,
Spain
3
Hamburger Sternwarte, Universität Hamburg,
Gojenbergsweg 112,
21029
Hamburg,
Germany
4
Centro de Astrobiología, CSIC-INTA, ESAC campus, Camino bajo del castillo s/n,
28692 Villanueva de la Cañada,
Madrid,
Spain
5
Instituto de Astrofísica de Canarias (IAC), Calle Vía Lactea s/n,
38200
La Laguna,
Tenerife,
Spain
6
Departamento de Astrofísica, Universidad de La Laguna,
38026
La Laguna,
Tenerife,
Spain
7
Institut für Astrophysik, Georg-August-Universität,
37077
Göttingen,
Germany
8
Institut de Ciències de l’Espai (CSIC-IEEC), Campus UAB, c/ de Can Magrans s/n,
08193
Bellaterra,
Barcelona,
Spain
9
Institut d’Estudis Espacials de Catalunya (IEEC),
08034
Barcelona,
Spain
10
Landessternwarte, Zentrum für Astronomie der Universität Heidelberg,
Königstuhl 12,
69117
Heidelberg,
Germany
11
Centro Astronónomico Hispano Alemán, Observatorio de Calar Alto, Sierra de los Filabres,
04550
Gérgal,
Spain
12
School of Physics and Astronomy, Queen Mary, University of London,
327 Mile End Road,
London,
E1 4NS,
UK
13
Thüringer Landessternwarte Tautenburg,
Sternwarte 5,
07778
Tautenburg,
Germany
14
Max-Planck-Institut für Astronomie,
Königstuhl 17,
69117
Heidelberg,
Germany
15
Departamento de Física de la Tierra y Astrofísica, Facultad de Ciencias Físicas, Universidad Complutense de Madrid,
28040
Madrid,
Spain
16
School of Geosciences, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University,
Tel Aviv,
6997801,
Israel
Received:
28
September
2018
Accepted:
3
November
2018
Aims. We explore the capabilities of CARMENES for characterising hot-Jupiter atmospheres by targeting multiple water bands, in particular, those at 1.15 and 1.4 μm. Hubble Space Telescope observations suggest that this wavelength region is relevant for distinguishing between hazy and/or cloudy and clear atmospheres.
Methods. We observed one transit of the hot Jupiter HD 189733 b with CARMENES. Telluric and stellar absorption lines were removed using SYSREM, which performs a principal component analysis including proper error propagation. The residual spectra were analysed for water absorption with cross-correlation techniques using synthetic atmospheric absorption models.
Results. We report a cross-correlation peak at a signal-to-noise ratio (S/N) of 6.6, revealing the presence of water in the transmission spectrum of HD 189733 b. The absorption signal appeared slightly blueshifted at –3.9 ± 1.3 km s−1. We measured the individual cross-correlation signals of the water bands at 1.15 and 1.4 μm, finding cross-correlation peaks at S/N of 4.9 and 4.4, respectively. The 1.4 μm feature is consistent with that observed with the Hubble Space Telescope.
Conclusions. The water bands studied in this work have been mainly observed in a handful of planets from space. Being able also to detect them individually from the ground at higher spectral resolution can provide insightful information to constrain the properties of exoplanet atmospheres. Although the current multi-band detections can not yet constrain atmospheric haze models for HD 189733 b, future observations at higher S/N could provide an alternative way to achieve this aim.
Key words: planets and satellites: atmospheres / planets and satellites: individual: HD 189733 b / techniques: spectroscopic / infrared: planetary systems
© ESO 2019
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