天の川銀河最大の恒星ブラックホール発見 質量は太陽の３３倍

【パリＡＦＰ＝時事】天の川銀河（銀河系）でこれまでに観測された中で最大となる恒星ブラックホールが発見されたことが１６日、発表された。太陽の３３倍の質量があるという。（写真は資料写真）
　国立科学研究センター（ＣＮＲＳ）の天文学者はＡＦＰに対し、このブラックホールは欧州宇宙機関（ＥＳＡ）の宇宙望遠鏡「ガイア」が収集したデータから「偶然」発見され、「ガイアＢＨ３」と名付けられたとパリ天文台で語った。わし座の方向にあり、地球からは２０００光年離れているという。
　恒星ブラックホールは大質量星が寿命を迎えて崩壊する際にできる。超大質量ブラックホールよりも小さい。
　ガイアＢＨ３は「休眠状態」のブラックホールでＸ線を発していないため、発見が難しかったとされる。
　ＥＳＡの宇宙望遠鏡ガイアは過去１０年間、地球から１５０万キロ離れた地点で観測を続け、２０２２年には１８億個以上の天体の位置と動きを３Ｄマップ化した。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2024/04/16-18:11）

Astronomers identified the largest stellar black hole yet discovered in the Milky Way, with a mass 33 times that of the Sun, according to a study published on Tuesday.
The black hole, named Gaia BH3, was discovered by chance from data collected by the European Space Agency's Gaia mission, an astronomer from the National Centre for Scientific Research (CNRS) at the Observatoire de Paris, Pasquale Panuzzo, told AFP.
Gaia, which is dedicated to mapping the Milky Way galaxy, located BH3 2,000 light years away from Earth in the Aquila constellation.
As Gaia's telescope can give a precise position of stars in the sky, astronomers were able to characterise their orbits and measure the mass of the star's invisible companion -- 33 times that of the Sun.
Further observations from on-the-ground telescopes confirmed that it was a black hole with a mass far greater than the stellar black holes already in the Milky Way.
No one was expecting to find a high-mass black hole lurking nearby, undetected so far. This is the kind of discovery you make once in your research life, Panuzzo said in a press release.
The stellar black hole was discovered when scientists spotted a wobbling motion on the companion star that was orbiting it.
We could see a star a little smaller than the Sun (around 75 percent of its mass) and brighter, that revolved around an invisible companion, Panuzzo said.
Stellar black holes are created from the collapse of massive stars at the end of their lives and are smaller than supermassive black holes whose creation is still unknown.
Such giants have already been detected in distant galaxies via gravitational waves.
But never in ours, said Panuzzo.
BH3 is a dormant black hole and is too far away from its companion star to strip it of its matter and therefore emits no X-rays -- making it difficult to detect.
Gaia's telescope identified the first two inactive black holes (Gaia BH1 and Gaia BH2) in the Milky Way.
Gaia has been operating 1.5 million kilometres from Earth for the past 10 years and in 2022 delivered a 3D map of the positions and motions of more than 1.8 billion stars.