Best hint yet: Star collapsed into black hole without supernova
It is easy to observe when stars explode in a supernova and become a black hole. It is different when they simply collapse.
Artistic representation of the black hole, with infalling material still glowing
(Image: Keith Miller, Caltech / IPAC - SELab)
Years ago, a space telescope apparently observed the direct collapse of a star into a black hole, but this was only discovered now. Columbia University in New York has made this public. According to reports, this happened in the Andromeda galaxy, a neighbor of our Milky Way. While such a process may have been observed before, it was at a distance ten times greater and 100 times fainter, writes the research group. Therefore, this is by far the best observation of such an event. At the same time, the star was so massive that, according to current understanding, it should have ended in a supernova. Why this did not happen is unclear.
Overlooked for years
The disappearing star was found in data from NASA's Neowise space telescope. It recorded how the object designated M31-2014-DS1 slowly brightened in the infrared spectrum in 2014, writes the research group. Between 2017 and 2022, it then abruptly became darker and darker until it could no longer be detected at all. The researchers believe this should be interpreted as a failed supernova, in which the star collapsed directly into a black hole. Because the star ultimately had only about five times the mass of our sun and should therefore be too small for this process, it underscores that we do not yet understand it sufficiently.
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While it is easy to detect bright supernova explosions, it is remarkably difficult to identify stars that simply disappear, explains lead researcher Kishalay De. Nevertheless, he finds it shocking that such a massive star can “in principle disappear and then die without an explosion without anyone noticing for five years.” This has implications for our understanding of how stars end. The finding shows that it can happen quietly and unnoticed, even if it occurs relatively close by. The research group has published its work in the scientific journal Science.
(mho)
