Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b

Hoeijmakers, Jens; Ehrenreich, David; Heng, Kevin; Kitzmann, Daniel; Grimm, Simon; Allart, Romain; Deitrick, Russell John; Wyttenbach, Aurélien; Oreshenko, Maria; Pino, Lorenzo; Rimmer, Paul B.; Molinari, Emilio; Di Fabrizio, Luca (2018). Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b. Nature, 560(7719), pp. 453-455. Macmillan Journals Ltd. 10.1038/s41586-018-0401-y

Text s41586-018-0401-y.pdf - Published Version Restricted to registered users only Available under License Publisher holds Copyright. Download (3MB)

To constrain the formation history of an exoplanet, we need to know its chemical composition. With an equilibrium temperature of about 4,050 kelvin, the exoplanet KELT-9b (also known as HD 195689b) is an archetype of the class of ultrahot Jupiters that straddle the transition between stars and gas-giant exoplanets and are therefore useful for studying atmospheric chemistry. At these high temperatures, iron and several other transition metals are not sequestered in molecules or cloud particles and exist solely in their atomic forms5. However, despite being the most abundant transition metal in nature, iron has not hitherto been detected directly in an exoplanet because it is highly refractory. The high temperatures of KELT-9b imply that its atmosphere is a tightly constrained chemical system that is expected to be nearly in chemical equilibrium and cloud-free, and it has been predicted that spectral lines of iron should be detectable in the visible range of wavelengths. Here we report observations of neutral and singly ionized atomic iron (Fe and Fe⁺) and singly ionized atomic titanium (Ti⁺) in the atmosphere of KELT-9b. We identify these species using cross-correlation analysis of high-resolution spectra obtained as the exoplanet passed in front of its host star. Similar detections of metals in other ultrahot Jupiters will provide constraints for planetary formation theories.

Interest & Impact

Downloads

3 since deposited on 03 Jun 2019
0 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item