There are so many stars out there in the entire Milky Way galaxy (roughly 200 billion), but some of them keep leaving astronomers speechless. One of those stars is S4716, one that hurtles around the supermassive black hole known as Sagittarius A* from the center of our Milky Way galaxy.
The star in question is also orbiting very close to the black hole itself – so close that it needs only 4 years to complete a full orbit. Reaching a velocity of 18 million mph, the object is the fastest known star that orbits the black hole from the heart of our galaxy, according to space.com. However, astronomers needed many years of observations to confirm the huge speed of the S4716 star. They gathered data about the celestial object using five telescopes: NACO, GRAVITY, and SINFONI, which are instruments mounted on the Very Large Telescope from Chile, as well as the OSIRIS and NIR2 instruments of the Keck Observatory, which exists near the summit of Mauna Kea in Hawaii.
Orbiting very near Sagittarius A*
The S4716 star also orbits relatively close to the Sagittarius A* supermassive black hole, at 9.2 billion miles away, which is another pretty unusual thing. That’s indeed a huge distance for us humans. But for the Universe, it’s practically nothing. You can take into account only the fact that a single light-year means roughly 6 trillion miles. If the star gets close enough, the black hole will absorb it into oblivion.
Michael Zajaček from the Masaryk University in Brno, stated as space.com quotes:
The short-period, compact orbit of S4716 is quite puzzling,
Stars cannot form so easily near the black hole. S4716 had to move inwards, for example by approaching other stars and objects in the S cluster, which caused its orbit to shrink significantly.
The new research is available in The Astrophysical Journal.