Astronomers using the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument on ESO’s Very Large Telescope have discovered and immediately imaged a gigantic exoplanet orbiting young star YSES 2.
A direct view of the massive exoplanet YSES 2b and its host star. Image credit: ESO / SPHERE / VLT / Bohn et al.
YSES 2 is a K1 star located 359 light-years away in the southern constellation of Musca.
The star, also known as TYC 8984-2245-1, is only 13.9 million years old and belongs to a nearby group of stars called the Scorpius-Centaurus association.
The newly discovered planet, called YSES 2b, has a mass about 6.3 times that of Jupiter and orbits its parent star at a distance of 115 AU (astronomical units).
“YSES 2b is an important addition to the sparsely populated group of gas giants with a wide orbit,” said astronomer Alexander Bohn and colleagues from the Leiden Observatory.
The astronomers have detected the planet using the SPHERE instrument on ESO’s Very Large Telescope.
The discovery was made as part of the Young Suns Exoplanet Survey (YSES), which aims to detect and characterize planetary-mass companions as solar-type host stars in the Scorpius-Centaurus association.
“The great distance of YSES 2b from its star is a puzzle because it doesn’t seem to fit into one of the two best-known models for the formation of large gaseous planets,” said the researchers.
“If the planet had grown far from the star at its current location by means of nuclear accretion, it would be too massive because there is not enough material to make a huge planet this great distance from the star.”
“If the planet was created by the so-called gravitational instability in the planetary disk, it doesn’t seem heavy enough.”
“A third possibility is that the planet formed close to the star through nuclear accretion and then migrated outward.”
“Such a migration, however, would require the gravitational influence of a second planet, which the researchers have not yet found.”
“By exploring more Jupiter-like exoplanets in the near future, we will learn more about the formation processes of gas giants around sun-like stars,” Bohn concluded.
The discovery is reported in an article in the journal Astronomy and Astrophysics.
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Alexander J. Bohn et al. 2021. Discovery of a directly imaged planet for the young solar analog YSES 2. A&A 648, A73; doi: 10.1051 / 0004-6361 / 202140508