Journal
ASTROPHYSICAL JOURNAL LETTERS
Volume 907, Issue 1, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.3847/2041-8213/abd84f
Keywords
Exoplanet atmospheres; Bayesian statistics; Hot Jupiters; Chemical abundances
Categories
Funding
- European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program [758892]
- Science and Technology Funding Council (STFC) [ST/S002634/1, ST/T001836/1]
- STFC [ST/T001836/1] Funding Source: UKRI
Ask authors/readers for more resources
Recent studies have shown that ultra-hot Jupiters may have thermal inversions in their atmospheres, with optical absorbers like TiO, VO, FeH possibly present. The atmosphere of KELT-9 b, the hottest exoplanet known, is believed to be dominated by molecular species, with TiO, VO, FeH, and H- providing the best fit in analysis with data from HST, Spitzer, and TESS. The findings indicate a more complex picture of ultra-hot planets' atmospheres than previously thought.
Recent studies of ultra-hot Jupiters suggested that their atmospheres could have thermal inversions due to the presence of optical absorbers such as titanium oxide (TiO), vanadium oxide (VO), iron hydride (FeH), and other metal hydride/oxides. However, it is expected that these molecules would thermally dissociate at extremely high temperatures, thus leading to featureless spectra in the infrared. KELT-9 b, the hottest exoplanet discovered so far, is thought to belong to this regime and host an atmosphere dominated by neutral hydrogen from dissociation and atomic/ionic species. Here, we analyzed the eclipse spectrum obtained using the Hubble Space Telescope's Wide Field Camera 3 and, by utilizing the atmospheric retrieval code TauREx3, found that the spectrum is consistent with the presence of molecular species and is poorly fitted by a simple blackbody. In particular, we find that a combination of TiO, VO, FeH, and H- provides the best fit when considering Hubble Space Telescope (HST), Spitzer, and TESS data sets together. Aware of potential biases when combining instruments, we also analyzed the HST spectrum alone and found that TiO and VO only were needed in this case. These findings paint a more complex picture of the atmospheres of ultra-hot planets than previously thought.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available