In young planetary systems, powerful collisions usually occur, through which young planetary bodies of small size gradually merge and form larger and larger planets. In our solar system, the Earth and the Moon are supposedly the products of a giant collision of this kind. Astronomers suggest that such collisions should be widespread in young planetary systems, but observing them in the vicinity of other stars is very difficult.
In a new study, astronomers have found signs of a giant collision that took place in a nearby star system just 95 light-years from Earth. This star, dubbed HD 172555, formed only 23 million years ago and, as scientists suspect, traces of a recent collision between the planets are visible in the dust around this star.
The team, led by scientists at the Massachusetts Institute of Technology, USA, determined that the collision likely occurred between an Earth-like planet about the size of Earth and a smaller body about 200,000 years ago at speeds of about 10 kilometers per second.
Through radio observations, astronomers have discovered a gas, carbon monoxide, which indicates that such a high-speed collision caused part of the atmosphere of the larger planet to be ripped off – a high-energy event that could explain the observed gas and dust around the star.
“In our study, we observed for the first time the atmosphere lost to space by a planet in a collision in the vicinity of a star,” said lead author Tajana Schneiderman of the Massachusetts Institute of Technology.
In their work, Schneiderman and her team discovered, using the Atacama Large Millimeter Array (ALMA) radio observatory, signs of carbon monoxide in the HD 172555 star system. carbon monoxide was formed as a result of a collision between two planetary bodies no earlier than 200,000 years ago, when the atmosphere of the larger body was scattered into space near the star.
The research is published in the journal Nature.
