Issue |
A&A
Volume 682, February 2024
|
|
---|---|---|
Article Number | A48 | |
Number of page(s) | 12 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202347846 | |
Published online | 02 February 2024 |
β Pictoris b through the eyes of the upgraded CRIRES+
Atmospheric composition, spin rotation, and radial velocity★
1
Leiden Observatory, Leiden University,
PO Box 9513,
2300 RA
Leiden,
The Netherlands
e-mail: rlandman@strw.leidenuniv.nl
2
Aix-Marseille Univ., CNRS, CNES, LAM,
13388
Marseille,
France
3
Department of Physics, Centre for Exoplanets and Habitability, University of Warwick,
Gibbet Hill Road,
Coventry
CV4 7AL,
UK
4
Max-Planck Institut fur Astronomie,
Königstuh l17,
69117
Heidelberg,
Germany
5
IPAC, Mail Code 100-22, Caltech,
1200 E. California Boulevard,
Pasadena,
CA
91125,
USA
6
Instituto de Astrofísica de Andalucía (IAA-CSIC),
Glorieta de la Astronomía s/n,
18008
Granada,
Spain
Received:
31
August
2023
Accepted:
11
November
2023
Context. High-resolution spectrographs fed by adaptive optics (AO) provide a unique opportunity to characterize directly imaged exoplanets. Observations with such instruments allow us to probe the atmospheric composition, spin rotation, and radial velocity of the planet, thereby helping to reveal information on its formation and migration history. The recent upgrade of the Cryogenic High-Resolution Infrared Echelle Spectrograph (CRIRES+) at the VLT makes it a highly suitable instrument for characterizing directly imaged exoplanets.
Aims. In this work, we report on observations of β Pictoris b with CRIRES+ and use them to constrain the planets atmospheric properties and update the estimation of its spin rotation.
Methods. The data were reduced using the open-source pycrires package. We subsequently forward-modeled the stellar, planetary, and systematic contribution to the data to detect molecules in the planet’s atmosphere. We also used atmospheric retrievals to provide new constraints on its atmosphere.
Results. We confidently detected water and carbon monoxide in the atmosphere of β Pictoris b and retrieved a slightly sub-solar carbon-to-oxygen ratio, which is in agreement with previous results. The interpretation is hampered by our limited knowledge of the C/O ratio of the host star. We also obtained a much improved constraint on its spin rotation of 19.9 ± 1.0 kms−1, which gives a rotation period of 8.7 ± 0.8 h, assuming no obliquity. We find that there is a degeneracy between the metallicity and clouds, but this has minimal impact on the retrieved C/O, υ sin i, and radial velocity. Our results show that CRIRES+ is performing well and stands as a highly useful instrument for characterizing directly imaged planets.
Key words: techniques: spectroscopic / planets and satellites: individual: β pictoris b / planets and satellites: atmospheres / planets and satellites: gaseous planets / techniques: high angular resolution
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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