Rare-Earth elements detected in the atmosphere of an exoplanet for the first time

KELT 9B illustration
Illustration of KELT-9B orbiting its host star, KELT-9. (Credits - NASA/JPL-Caltech)

The hottest exoplanet which is known to scientists till now is the KELT-9b. In 2018, a group of researchers from universities in Bern and Geneva found signs of iron and titanium in gaseous form in its atmosphere. On top of that, scientists recently observed signs of gaseous sodium, magnesium and also rare metals such as scandium, yttrium.

The exoplanets are those planets which lie outside our solar system and revolve around stars other than Sun. There has been a discovery of almost 3000 exoplanets since the ’90s. Several of these planets have quite extreme conditions as compared to the planets in the solar system. Some of these planets orbit around the stars sometimes with the time of revolution being in the order of days. Planets of such kind do not exist in our solar system and they have often confused scientists about their existence. Scientists have been trying hard to understand how they are formed and what are they composed of.

The distance of KELT-9 from the earth is about 650 light years and is located in the constellation Cygnus. The exoplanet KELT-9b orbits at a very close distance around its star which has a very high temperature. Thus the atmosphere almost touches 4000 degrees Celsius and in this ultra-high temperature nearly all the elements are turned to their gaseous state and the molecules break down into atoms. Thus there is absolutely no presence of clouds in the atmosphere. The atoms which are present in the constituents of the atmosphere absorb very specific light rays and each individual atom has a distinct fingerprint of colours which is absorbed. The measurements of these fingerprints are done with the help of a spectrograph mounted on a huge telescope. This allows scientists to find out the composition of the atmospheres which are situated light years away.

This technique was used by the researchers from the Universities of Bern and Geneva and they had some interesting observations. Kevin Heng, who is the Director of the Center for Space and Habitability commented that they found traces of iron and titanium atoms in the atmosphere of KELT-9b with the help of HARPS-North spectrograph mounted on the Italian National Telescope. In total, they found 73 atoms which also included some of the rare Earth elements. Scientists found traces of sodium and magnesium which was never before detected in the atmospheres of an exoplanet before.

Scientists hope to find traces of life on the exoplanet using these techniques, thus finally detecting the creation of the solar system along with the beginning of life.


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