According to a recent research
published
in Proceedings of the Japan Academy, Series B, a star close to the
supermassive black hole at the heart of the Milky Way galaxy originated
outside the galaxy. This is the first time a star outside of our galaxy has
been discovered close to a supermassive black hole.
Sagittarius A*, the supermassive black hole in our galaxy's center, is
observed to be close to a large number of stars. However, the surrounding
environment is too hostile for stars to develop close to the black hole due
to its strong gravity. Every star that has been seen had to have developed
someplace else and moved in the direction of the black hole. The issue of
where the stars formed is raised by this.
According to research conducted by a multinational team under the direction
of Shogo Nishiyama at Miyagi University of Education, certain stars may have
originated from sources beyond the Milky Way entirely, which is farther
distant than previously believed. Over the course of eight years, the
researchers observed the star S0-6, which is just 0.04 light-years distant
from Sagittarius A*, using the Subaru Telescope.
They discovered that S0-6 is around 10 billion years old and that its
chemical makeup is comparable to that of stars in dwarf galaxies in
Sagittarius and the Small Magellanic Cloud, two galaxies outside of the
Milky Way.
The most plausible explanation for S0-6's composition is that it originated
in a tiny galaxy that is now extinct and was swallowed by the Milky Way when
it was orbiting the galaxy. This is the first empirical evidence that points
to some of the nearby stars of Sagittaius A* as having originated outside of
the galaxy.
S0-6 had to have traveled more than 50,000 light-years from beyond the
Milky Way to get to the area around Sagittarius A* over its 10 billion-year
existence. S0-6 most likely traveled about 50,000 light-years, descending
slowly in a spiral fashion to the center rather than in a straight
line.
Nishiyama claims that many questions remain. "Did S0-6 indeed come from a
galaxy other than our own? Was it traveling with other people or by itself?
We want to solve the mystery surrounding the stars close to the supermassive
black hole with more research."
Provided by
National Astronomical Observatory of Japan
