Black holes can be classified according to their mass. “Stellar black holes” are formed by the gravitational collapse of massive stars. Because they have little interaction with the surrounding environment, they are particularly difficult to search for, and they have not been “clearly discovered” outside the Milky Way in the past. Recently, astronomers announced the first excavation of the dormant stellar black hole VFTS 243, which is 9 times the mass of the sun and forms a binary system with a more massive blue giant star.
When a massive star with a mass about 20 times the mass of the sun uses up all its energy, gravitational collapse is an inevitable trend, and finally a stellar black hole (Stellar black hole) with a mass 5-10 times the mass of the sun may be formed in situ. When they are inactive, they cannot be seen even under the nose of the instrument, unless the black hole “feeds” and produces distinct X-ray signatures around it, in order to grasp the location of the black hole.
Or the stellar black hole and another star form a binary star system, then looking for stars that seem to orbit unknown things may represent the existence of black holes, but there have been studies in the past claiming to have found stellar black holes outside the Milky Way, but unfortunately the evidence is not impeccable .
In order to find black holes that cannot be directly observed, another group of astronomy teams used the Very Large Telescope to invest 6 years of observations to examine 1,000 massive stars (at least 8 times the mass of the sun) in the Tarantula Nebula region in the Large Magellanic Cloud. The spectrum found the orbital wobble data that is obviously “star-black hole”, and successfully found the target from the sample: a blue-white O-type star, about 160,000 light-years away from us.
Calculations show that the star is 25 times the mass of the Sun and appears to orbit an object every 10.4 days, forming the VFTS 243 binary system with an invisible “companion star” about 9 times the mass of the Sun. Since the upper limit of the mass of a neutron star is about 2.3 times that of the sun, what is there that weighs 9 solar masses and does not emit light? After ruling out all possibilities, the companion star is most likely a black hole, with an event horizon only about 27 kilometers wide.
Since there is no evidence that VFTS 243 had any remnants of an explosion, it will provide other theorists with a great opportunity to test the hypothesis that although the precursor of the companion star was a star, it collapsed directly into a black hole before it exploded.
The new paper was published in the journal Nature Astronomy.
(Source of the first image: European Southern Observatory)
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