University of Bern | 2019 May 09
KELT-9 b is the hottest exoplanet known to date. In the summer of 2018, a joint team of astronomers from the universities of Bern and Geneva found signatures of gaseous iron and titanium in its atmosphere. Now these researchers have also been able to detect traces of vaporized sodium, magnesium, chromium, and the rare-Earth metals scandium and yttrium.
Exoplanets are planets outside our solar system that orbit around stars other than the Sun. Since the discovery of the first exoplanets in the mid-90s, well over 3,000 exoplanets have been discovered. Many of these planets are extreme compared to the planets in our solar system: Hot gas giants that orbit incredibly close to their host stars, sometimes within periods of less than a few days. Such planets do not exist in our solar system, and their existence has defied predictions of how and why planets form. For the past 20 years, astronomers from all over the world have been working to understand where these planets come from, what they are made of, and what their climates are like.
KELT-9 is a star located 650 light-years from the Earth in the constellation Cygnus. Its exoplanet KELT-9 b exemplifies the most extreme of these so-called hot-Jupiters because it orbits very closely around its star that is almost twice as hot as the Sun. Therefore, its atmosphere reaches temperatures of around 4,000 °C. In such heat, all elements are almost completely vaporized and molecules are broken apart into their constituent atoms -- much like is the case in the outer layers of stars. This means that the atmosphere contains no clouds or aerosols and the sky is clear, mostly transparent to light from its star. ...
A Spectral Survey of an Ultra-Hot Jupiter. Detection of
Metals in the Transmission Spectrum of KELT-9 b ~ H.J. Hoeijmakers et al
- arXiv.org > astro-ph > arXiv:1905.02096 > 06 May 2019