Glimpse of planets around a multiple star system
doi:10.1038/nindia.2020.95 Published online 10 June 2020
Astronomers have discovered three proto-planets orbiting around GG Tau A, a multiple-star system, located about 489 light years away from the Earth1. The star system has a massive dust ring surrounded by a shallow disk.
The researchers say the proto-planets would eventually form planets and this discovery may shed new light on how planets form around multiple star systems in the universe.
Scientists have, so far, detected numerous planets around single stars such as the Sun. However, little is known about planets around multiple-star systems.
To better understand such systems, the scientists, including Liton Majumdar, an astronomer from the National Institute of Science Education and Research in Odisha, India, scanned the Taurus star-forming region using an array of radio telescopes parched in the Atacama Desert of Chile.
They have detected that one of the proto-planets, lying at almost 10 times the Sun-Neptune distance from the star system, is sucking in gas and dust from a surrounding disk. This has created a ‘hot spot’ that is much warmer than its surroundings and is rich in carbon monoxide gas.
They have also detected a spiral pattern, which is brightest at the hot-spot location, just outside the dust ring. One of the proto-planets probably produced this pattern.
The absence of a clear gap in gas or dust at the planet location means that its mass is significantly lower than that of Jupiter, but close to that of Neptune. This suggests that planets with a mass similar to Neptune may form in dense circumbinary disks orbiting binary stars, says Majumdar.
1. Phoung, N. T. et al. Planet-induced spirals in the circumbinary disk of GG Tauri A. Astron. Astrophys. 635, L9 (2020)