Nikolay K Nikolov
Solar-to-supersolar sodium and oxygen absolute abundances for a ‘hot Saturn’ orbiting a metal-rich star
Nikolov, Nikolay K; Sing, David K; Spake, Jessica J; Smalley, Barry; Goyal, Jayesh M; Mikal-Evans, Thomas; Wakeford, Hannah R; Rustamkulov, Zafar; Deming, Drake; Fortney, Jonathan J; Carter, Aarynn; Gibson, Neale P; Mayne, Nathan J
Authors
David K Sing
Jessica J Spake
Barry Smalley b.smalley@keele.ac.uk
Jayesh M Goyal
Thomas Mikal-Evans
Hannah R Wakeford
Zafar Rustamkulov
Drake Deming
Jonathan J Fortney
Aarynn Carter
Neale P Gibson
Nathan J Mayne
Abstract
We present new analysis of infrared transmission spectroscopy of the cloud-free hot-Saturn WASP-96b performed with the Hubble and Spitzer Space Telescopes (HST and Spitzer). The WASP-96b spectrum exhibits the absorption feature from water in excellent agreement with synthetic spectra computed assuming a cloud-free atmosphere. The HST-Spitzer spectrum is coupled with Very Large Telescope (VLT) optical transmission spectroscopy which reveals the full pressure-broadened profile of the sodium absorption feature and enables the derivation of absolute abundances. We confirm and correct for a spectral offset of $\Delta R_{{\rm p}}/R_{\ast }=(-4.29^{+0.31}_{-0.37})\, \times 10^{-3}$ of the VLT data relative to the HST-Spitzer spectrum. This offset can be explained by the assumed radius for the common-mode correction of the VLT spectra, which is a well-known feature of ground-based transmission spectroscopy. We find evidence for a lack of chromospheric and photometric activity of the host star which therefore make a negligible contribution to the offset. We measure abundances for Na and O that are consistent with solar to supersolar, with abundances relative to solar values of $21^{+27}_{-14}$ and $7^{+11}_{-4}$, respectively. We complement the transmission spectrum with new thermal emission constraints from Spitzer observations at 3.6 and 4.5 $\mu$m, which are best explained by the spectrum of an atmosphere with a temperature decreasing with altitude. A fit to the spectrum assuming an isothermal blackbody atmosphere constrains the dayside temperature to be Tp = 1545 ± 90 K.
Citation
Nikolov, N. K., Sing, D. K., Spake, J. J., Smalley, B., Goyal, J. M., Mikal-Evans, T., …Mayne, N. J. (2022). Solar-to-supersolar sodium and oxygen absolute abundances for a ‘hot Saturn’ orbiting a metal-rich star. Monthly Notices of the Royal Astronomical Society, 515(2), 3037-3058. https://doi.org/10.1093/mnras/stac1530
Journal Article Type | Article |
---|---|
Acceptance Date | May 30, 2022 |
Online Publication Date | Jun 7, 2022 |
Publication Date | Aug 4, 2022 |
Deposit Date | May 30, 2023 |
Journal | Monthly Notices of the Royal Astronomical Society |
Print ISSN | 0035-8711 |
Electronic ISSN | 1365-2966 |
Publisher | Oxford University Press |
Peer Reviewed | Peer Reviewed |
Volume | 515 |
Issue | 2 |
Pages | 3037-3058 |
DOI | https://doi.org/10.1093/mnras/stac1530 |
Keywords | Space and Planetary Science, Astronomy and Astrophysics |
Public URL | https://keele-repository.worktribe.com/output/427372 |
Publisher URL | https://academic.oup.com/mnras/article/515/2/3037/6603842 |
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