The star HD 65907 looks young and hot. However, its spectrum is extremely low in metals, indicating that it was formed during the time of the early Universe. Scientists were able to determine that the reason for this is that they were formed by the merger of two other luminaries.
The star HD 65907
Scientists have solved the mystery of the mysterious star HD 65907. At first glance, it seems relatively young and hot. The age of the luminary is estimated at 5 billion years. However, spectroscopic studies have shown that its composition is extremely low in metals, that is, elements heavier than hydrogen and helium.
It usually happens only in very old stars, which belong to the first generations that existed in the Universe. But then how to explain the high temperature, because during this time such a luminary would have to spend all its fuel and turn into a black hole or neutron star.
HD 65907 must have died, but it has somehow been resurrected. Furthermore, it is not like most young luminaries circling peacefully in the plane of the Galaxy. Instead, its orbit is extremely chaotic. And now scientists know the reason for all this: it is a blue doohickey.
The blue doohickeys
Blue doohickeys have been known to scientists for several decades. Their phenomenon is closely related to the so-called main sequence in the Hertzsprung-Russell diagram. There is a point on it, to the right of which no star can be located. When it is reached, thermonuclear processes begin to inflate its envelope and it begins to turn first into a subgiant and then into a red giant.
However, there are a small number of stars that are on the diagram to the left of this point. They should have started to turn into giants long ago, but for some reason, they stayed on the main sequence. They’re what are known as blue doohickeys. They are believed to be formed by the merger of two stars.
This is the process that explains the nature of the “resurrection” of HD 65907. There were once two stars, possibly white dwarfs, born 11 billion years ago. They merged together and gave birth to a new star.
Actually, that’s not what’s so interesting about HD 65907. Usually, blue doohickeys are found within star clusters. But this one was a loner. Maybe it was ejected from where it was born.
Provided by phys.org
