Nicholas Borsato
From Sweden to Australia, I'm on a quest to unveil the secrets of alien atmospheres.
The Mantis Network : III. Expanding the limits of chemical searches within ultra-hot Jupiters: New detections of Ca I, v I, Ti I, Cr I, Ni I, Sr II, Ba II, and Tb II in KELT-9 b
Author
Summary, in English
Cross-correlation spectroscopy is an invaluable tool in the study of exoplanets. However, aliasing between spectral lines makes it vulnerable to systematic biases. This work strives to constrain the aliases of the cross-correlation function to provide increased confidence in the detections of elements in the atmospheres of ultra-hot Jupiters (UHJs) observed with high-resolution spectrographs. We use a combination of archival transit observations of the UHJ KELT-9 b obtained with the HARPS-N and CARMENES spectrographs and show that it is possible to leverage each instrument's strengths to produce robust detections at a substantially reduced signal-to-noise. Aliases that become present at low signal-to-noise regimes are constrained through a linear regression model. We confirm previous detections of H I, Na I, Mg I, Ca II, Sc II, Ti II, Cr II, Fe I, and Fe II, and detect eight new species, Ca I, Cr I, Ni I, Sr II, and Tb II, at the 5δ level, and Ti I, V I, and Ba II above the 3δ level. Ionised terbium (Tb II) has never before been seen in an exoplanet atmosphere. We further conclude that a 5δ threshold may not provide a reliable measure of confidence when used to claim detections, unless the systematics in the cross-correlation function caused by aliases are taken into account.
Department/s
- Astrophysics
- eSSENCE: The e-Science Collaboration
Publishing year
2023
Language
English
Publication/Series
Astronomy and Astrophysics
Volume
673
Document type
Journal article
Publisher
EDP Sciences
Topic
- Astronomy, Astrophysics and Cosmology
Keywords
- Planets and satellites: atmospheres
- Planets and satellites: gaseous planets
- Techniques: spectroscopic
Status
Published
ISBN/ISSN/Other
- ISSN: 0004-6361