Evidence for TiO in the Atmosphere of the Hot Jupiter HAT-P-65 b
Abstract
We present the low-resolution transmission spectra of the puffy hot Jupiter HAT-P-65b (0.53 MJup, 1.89 RJup, Teq = 1930 K), based on two transits observed using the OSIRIS spectrograph on the 10.4 m Gran Telescopio CANARIAS. The transmission spectra of the two nights are consistent, covering the wavelength range 517-938 nm and consisting of mostly 5 nm spectral bins. We perform equilibrium-chemistry spectral retrieval analyses on the jointly fitted transmission spectrum and obtain an equilibrium temperature of ${1645}_{-244}^{+255}$ K and a cloud coverage of ${36}_{-17}^{+23}$ %, revealing a relatively clear planetary atmosphere. Based on free-chemistry retrieval, we report strong evidence for titanium oxide (TiO). Additional individual analyses in each night reveal weak-to-moderate evidence for TiO in both nights, but moderate evidence for Na or VO only in one of the nights. Future high-resolution Doppler spectroscopy as well as emission observations will help confirm the presence of TiO and constrain its role in shaping the vertical thermal structure of HAT-P-65b's atmosphere.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 2021
- DOI:
- 10.3847/2041-8213/abfbe1
- arXiv:
- arXiv:2104.13058
- Bibcode:
- 2021ApJ...913L..16C
- Keywords:
-
- Exoplanet atmospheres;
- Exoplanet atmospheric composition;
- Transmission spectroscopy;
- Hot Jupiters;
- Exoplanets;
- 487;
- 2021;
- 2133;
- 753;
- 498;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 15 pages, 8 figures, accepted for publication in ApJL