Budding exoplanets found in Taurus star-forming region
12 of the 32 stars observed feature rings and gaps that are usually carved by planets in the process of formation
An international team of astronomers has discovered a "treasure trove" of exoplanets in the Taurus constellation. The team, which included astronomers from the University of Arizona's Steward Observatory and Lunar and Planetary Laboratory, carried out a survey of protoplanetary disks surrounding young stars in the Taurus star-forming region, and found several disks exhibiting features suggestive of the presence of forming planets.
Protoplanetary disks are the rotating circular formations of gas and dust typically spotted around newborn stars. These disks are also considered accretion disks for the star, as the material may fall on to the surface of the star.
Astronomers in the study used the Atacama Large Millimetre Array (ALMA) in Chile to observe 32 stars surrounded by protoplanetary disks in the Taurus star-forming region. This region is located about 450 light-years from Earth; it is a massive cloud of dust and gas, and hosts a stellar nursery containing hundreds of newly formed stars. It is the nearest large star formation region to the Earth.
Astronomers found that 12 of the 32 stars they studied featured rings and gaps that are usually carved by planets in the process of formation.
"This is fascinating because it is the first time that exoplanet statistics, which suggest that super-Earths and Neptunes are the most common type of planets, coincide with observations of protoplanetary disks," said Feng Long, a doctoral student at the Kavli Institute for Astronomy and Astrophysics at Peking University in Bejing, China, and the lead author of the paper.
Astronomers also spotted some protoplanetary disks with multiple rings and gaps, which they say were more massive and more extended, suggesting the presence of multi-planet systems in the making.
The group now plans to increase ALMA's resolution to about five astronomical units and to make its antennas more sensitive to other frequencies, to investigate protoplanetary disks in other star-forming systems.
The team believes these new results could help improve their understanding of the origins of the rings and gaps around stars.
The detailed findings of the study are published in Astrophysical Journal.