In the atmosphere of the hottest exoplanets found atomic iron

Astronomers have confirmed the existence of iron atoms on the day side Altragracia in the atmosphere of Jupiter KELT-9b — the hottest exoplanets. The opening allows you to understand how to form and evolyutsioniruet such exoplanets. Preprint available on the portal arXiv.org

Altragracia Jupiters are distinguished as a subclass of hot Jupiters. These gas giants, weighing no more than 13.6 Jupiter masses are tidal capture their stars, which always faces the luminary of the same party. The periods of revolution of these exoplanets are only a few hours or days, and the temperature of their outer layers in the daylight hemisphere is often above two and a half thousand Kelvin. The study of such objects interesting from the point of view of understanding the complex dynamics of the atmosphere and various chemical processes taking place in it, as well as imposing constraints on models of formation and evolution of hot gas giants.

KELT-9b, belonging to ultragrain to Jupiter is in the star system of spectral class A, located at a distance of 650 light-years from the Sun in the constellation of Cygnus. Distance from the exoplanet to the star is only 0.03 astronomical units, and a year on it lasts 1,48 earth day. The mass of KELT-9b is estimated at 2.44 mass of Jupiter, the radius is 1.78 radii of Jupiter. It’s the hottest of the currently known exoplanets, its equilibrium temperature is 4050 Kelvin.

Astronomers headed by Lorenzo Pino (Pino Lorenzo) from the University of Amsterdam have published the results of observations of KELT-9b, which took place on 22-23 July 2018 with the spectrograph HARPS-North, established by 3.58-m telescope TNG (Telescopio Nazionale Galileo) on the island of La Palma. Previously by another research group using this tool, first discovered in the atmosphere of this extrasolar planets by the method of absorption spectroscopy of a couple of yttrium, scandium, and chromium, and also received evidence to its content of ions and atoms of iron, however, these data need re-examination. Iron is of particular interest to scientists, as knowing its concentration in the atmosphere of extrasolar planets can be assessed the metallicity and to compare it with the metallicity of their parent stars.

A feature of the new observations is that the radiation from the day side of the exoplanet were recorded directly. This allowed the scientists to establish that in the atmosphere of KELT-9b, there is a thermal inversion, its outer layers are hotter than the inner, due to the content of iron atoms at the level several times higher than its content in the star. It is assumed that the iron clouds reside at altitudes where the pressure is from 10-3 to 10-5 bar. In the future, scientists intend to determine more precisely the chemical composition of the atmosphere of the exoplanet with the space telescope “Hubble”.

Earlier we talked about how astronomers have revealed the disintegration of the atoms of molecular hydrogen in the atmosphere of KELT-9b, not found Rayleigh scattering in the atmosphere of a hot Jupiter for the first time found in her a titanium oxide, and also confirmedthat ultragreen Jupiter WASP-76b are iron rains.

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