The neighborhood of the black hole near the center of our galaxy consists of a densely packed cluster of stars. This cluster, known as the S cluster, involves more than a hundred stars that vary in brightness and mass. In particular, S stars move particularly fast.
Using continuously refining methods of analysis and observations covering almost twenty years, scientists at the University of Cologne and Masaryk University in Brno (Czech Republic) have discovered the fastest known star, which travels around a black hole in record time.
The star called S4716 takes only four years to travel around the black hole at the center of our galaxy– Sagittarius A*. It travels 8000 kilometers per second. The star has the shortest orbital period around the black hole. It comes as close as 100 AU (astronomical unit) to the black hole.
Dr. Florian Peissker, a lead author of the new study, said, “For a star to be in a stable orbit so close and fast in the vicinity of a supermassive black hole was completely unexpected and marks the limit that can be observed with traditional telescopes.”
“Moreover, the discovery sheds new light on the origin and evolution of the orbit of fast-moving stars in the heart of the Milky Way. The short-period, compact orbit of S4716 is quite puzzling,” Michael Zajaček, an astrophysicist at Masaryk University in Brno was involved in the study. “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.”
Journal Reference:
- Florian Peißker, Andreas Eckart et al. Observation of S4716—a Star with a 4 yr Orbit around Sgr A*. The Astrophysical Journal, Volume 933, Number 1. DOI: 10.3847/1538-4357/ac752f