The mysterious disappearance of stars may sound like a sci-fi movie scenario, but it is a reality; in the last 70 years, about 100 stars have disappeared from the landscape, all without a concrete explanation.
Their disappearance was brought into focus in 2019 with the VASCO (Vanishing and Appearing Sources during a Century of Observations) project, which compared images taken by the US Naval Observatory since 1949 with images from the Pan-STARRS survey taken between 2010 and 2014.
The software used by the project team came up with about 150,000 potential light sources that have since disappeared, reduced to 23,667 after comparing the list with other datasets.
“At this point, it would have been useful to use image differentiation software to compare the images and identify any obvious differences in pairs of highly similar images,” the team wrote in the study describing its findings. IFLScience.
“But because we’re comparing images taken with very different telescopes, instruments and methods, we don’t gain much advantage by taking this step.”
About 100 stars disappeared from the landscape
Instead, they manually sifted through the remaining images to rule out those resulting from camera malfunctions or other errors, and came up with about 100 promising candidates for real light sources that have disappeared from our line of sight.
Stars can dim like Betelgeuse or explode like a supernova, leaving a glow for hours or days, but generally they don’t just disappear from the landscape – so why can’t we see them anymore?
It could be gravitational lensing, where space-time is warped by extremely heavy objects that sometimes magnify distant objects, or other short bursts of light, such as gamma-ray bursts, which are captured in older studies. Objects moving closer, such as asteroids, could also explain these disappearances.
Another possible explanation is that they failed to go supernova, instead collapsing into a black hole. Although this is believed to be incredibly rare, a recent study has provided some tentative support for this theory.
Stars can dim or explode as a supernova
The study’s authors looked at a binary star system on the edge of the Milky Way, known as VFTS 243, consisting of a main-sequence O star and a black hole that orbit each other every 10.4 days, looking for signs – namely baryonic mass ejections and “birth shocks” – of black hole formation following a supernova explosion.
In this way, they found evidence that the black hole could have formed through total collapse and that this could explain the sudden disappearance of some stars.
“If one were to sit and watch a visible star go through a total collapse, it might be, at the right moment, like watching a star suddenly go out and disappear from the heavens. The collapse is so complete that no explosion occurs, nothing escapes, and no bright supernova would be visible in the night sky,” said study co-author Alejandro Vigna-Gómez.
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Source: www.descopera.ro
