Confusing data from the Gaia spacecraft may reveal one of the most sought-after types of objects in the Milky Way.
Gaia is a small spacecraft launched by the European Space Agency (ESA) that acts as a sky survey satellite, mapping the Milky Way.
According to Science Alert, when looking towards a location 5,825 light-years away from Earth, Gaia discovered a massive red giant star seemingly dancing.
Graphic depicting the Gaia spacecraft, a red giant star, and a black hole, along with actual images from astronomical data – (Photo: Song Wang/ESA).
Red giant stars are dying stars that expand rapidly for a short period before collapsing. Our Sun will also transform into this type of star in about 5 billion years, potentially swelling enough to engulf Mercury, Venus, and Earth.
However, the signals that Gaia received from this new red giant star are quite distinct. It appears to be slowly dancing in orbit with an unseen companion star.
Yet, no companion star can be observed alongside this red giant.
Based on the behavior of the red giant, a research team led by Dr. Song Wang from the Chinese Academy of Sciences estimated that the mass of this invisible companion object is only 3.6 times that of the Sun.
All calculations suggest that it can only be a black hole.
Additionally, its surprisingly wide circular orbital formation challenges current binary evolution theories and supernova explosion models, making it a treasure for researchers.
The red giant-black hole pair is collectively named G3425, and may have formed from the second death of a star significantly larger than the Sun.
After exploding into a red giant and collapsing for the first time, that star became a small, very dense neutron star. After some time, this neutron star continued to explode and collapsed into a black hole.
According to a publication in Nature, this black hole is estimated to weigh about 3.6 times the mass of the Sun.
Previously, the smallest black holes discovered weighed at least 5 times the mass of the Sun. Therefore, G 3425 has set a new record for the smallest type of black hole that could exist.
The dancing red giant accompanying the black hole is also intriguing.
The red giant in G3425 has an estimated mass of about 2.7 times that of the Sun, moving in a relatively wide orbit, taking about 880 days to complete one orbit around a common center with the black hole.
