Astronomers using the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument on ESO’s Very Large Telescope have discovered and directly imaged a giant exoplanet orbiting the young star YSES 2.
A direct image of the massive exoplanet YSES 2b and its host star. Image credit: ESO / SPHERE / VLT / Bohn et al.
YSES 2 is a K1-type star located 359 light-years away in the southern constellation of Musca.
Also known as TYC 8984-2245-1, the star is only 13.9 million years old, and belongs to a nearby group of stars called the Scorpius-Centaurus association.
The newfound planet, named YSES 2b, has a mass of 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 wide-orbit gas giant companions,” said Leiden Observatory astronomer Alexander Bohn and colleagues.
The astronomers 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 to solar-type host stars in the Scorpius-Centaurus association.
“The large distance from YSES 2b to its star presents a puzzle, because it does not seem to fit either of the two most well-known models for the formation of large gaseous planets,” the researchers said.
“If the planet had grown in its current location far from the star by means of core accretion, it would be too heavy because there is not enough material to make a huge planet at this large distance from the star.”
“If the planet was created by so-called gravitational instability in the planetary disk, it appears to be not heavy enough.”
“A third possibility is that the planet formed close to the star by core accretion and then migrated outwards.”
“Such a migration, however, would require the gravitational influence of a second planet, which the researchers have not yet found.”
“By investigating 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 a paper in the journal Astronomy & Astrophysics.
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Alexander J. Bohn et al. 2021. Discovery of a directly imaged planet to the young solar analog YSES 2. A&A 648, A73; doi: 10.1051/0004-6361/202140508
