‘Homeless’ planet without a star found

MONTREAL (UPI) -- A “homeless” planet that is not orbiting a star and thus is free of any gravitation link has been discovered, Canadian and European astronomers are reporting.

University of Montreal researchers and European colleagues said it is the first isolated planet of its kind ever to be observed.

“Although theorists had established the existence of this type of very cold and young planet, one had never been observed until today,” astrophysicist Etienne Artigau said in a University of Montreal release Wednesday.

The planet dubbed CFBDSIR2149 is located within a group of very young stars known as the AB Doradus Moving Group but is not gravitationally linked to any of them and has the specific criteria of mass, temperature and age to be designated as a “planet.”

“Over the past few years, several objects of this type have been identified, but their existence could not be established without scientific confirmation of their age,” Montreal doctoral student Jonathan Gagne said.

“Astronomers weren‘t sure whether to categorize them as planets or as Brown dwarfs. Brown dwarfs are what we could call failed stars, as they never manage to initiate nuclear reactions in their centers.”

Researchers say the isolated planet, about seven times the size of Jupiter, could have been flung away from other bodies during its formation.

<관련 한글 기사>

’공전하지 않는’ 행성, 최초로 발견!

별 주위를 공전하지 않아 어떠한 중력으로부터든지 자유로운 행성이 발견되었다.

캐나다와 유럽의 천문학자들에 따르면 이렇게 따로 운동하는 행성이 관측된 것은 사상 처음이라고 한다.

몬트리올 대학의 천체물리학자 에티엔 아티고는 "이론학자들이 이런 아주 춥고 어린 행성이 존재했다고 했지만 지금까지 관측된 적은 없었다"라고 말햇다.

CFBDSIR2149라고 명명된 이 행성은 'AB 황새치자리'라는 신생 행성 그룹에 위치해있지만 중력적으로 어떤 행성에도 끌리지 않으며 ’행성’이라고 불릴 만한 질량, 온도, 나이의 기준에 부합한다.

이 별도로 움직이는 행성은 목성 크기의 7배에 달하며 생성 당시 다른 행성에서 떨어져 나왔을 가능성도 있다.

그러나 학자들은 CFBDSIR2149가 갈색왜성일 가능성을 완전히 배제하지는 않았다.

(코리아헤럴드)