{"id":17725,"date":"2022-02-02T08:06:03","date_gmt":"2022-02-02T08:06:03","guid":{"rendered":"https:\/\/www.innovationnewsnetwork.com\/?p=17725"},"modified":"2022-02-02T08:06:03","modified_gmt":"2022-02-02T08:06:03","slug":"astronomers-question-whether-dying-stars-can-still-cause-planet-formation","status":"publish","type":"post","link":"https:\/\/www.innovationnewsnetwork.com\/astronomers-question-whether-dying-stars-can-still-cause-planet-formation\/17725\/","title":{"rendered":"Astronomers question whether dying stars can still cause planet formation"},"content":{"rendered":"
Planets are typically not a lot older than the stars in which they revolve around. For example, the Sun was born 4.6 bn years ago, and not long after that the Earth was formed.<\/p>\n
However, KU Leuven astronomers have discovered that a completely different scenario could also be possible. Even if a star is near to death, some types of stars can still possibly form planets, suggesting that theories on planet formation will need to be adjusted.<\/p>\n
Planets, such as Earth, were formed not long after the Sun. Our Sun started to burn 4.6 bn years ago, and in the next million years, the matter around it was clumped into protoplanets. The birth of the planets in that protoplanetary disc, with the Sun in the middle, explains why they all orbit the same plane.<\/p>\n
However, such discs of dust and gas need not necessarily surround only newborn stars. They can also develop independently from star formation, for instance around binary stars of which one is dying. When the end approaches for a medium-sized star (such as the Sun), it catapults the outer part of its atmosphere into space, after which it develops into a white dwarf.<\/p>\n
However, in the case of binary stars, the gravitational pull of the second star causes the matter ejected by the dying star to form a flat, rotating disc. Moreover, this disc strongly resembles the protoplanetary discs that astronomers observe around young stars elsewhere in the Milky Way.<\/p>\n
Although, an international team of astronomers led by KU Leuven researchers discovered that the discs surrounding evolved binary stars display signs that could point to planet formation. What is more, their observations highlights that this is the case for one in 10 of these binary stars.<\/p>\n
\u201cIn 10% of the evolved binary stars with discs that we studied, we can see a large cavity in the disc,\u201d explained Jacques Kluska, KU Leuven<\/a> astronomer and first author of the article in the journal\u00a0Astronomy & Astrophysics<\/em>\u00a0in which the discovery is described. \u201cThis is an indication that something is floating around there that has collected all matter in the area of the cavity.\u201d<\/p>\n The clean-up of the matter could be the work of a planet, indicating that the planet might not have formed at the very beginning of one of the binary stars\u2019 life, but instead at the end. The astronomers moreover observed further indications for the presence of such planets.<\/p>\n \u201cIn the evolved binary stars with a large cavity in the disc, we saw that heavy elements such as iron were very scarce on the surface of the dying star,\u201d commented Kluska. \u201cThis observation leads one to suspect that dust particles rich in these elements were trapped by a planet.\u201d<\/p>\nSecond-generation planet<\/h3>\n