An international study has discovered a star, S5-HVS1, traveling at more than 6 million km/h. The star is traversing the Milky Way after being pushed away by Sagittarius A*, the supermassive black hole at the center of our galaxy. Professor Emeritus Gary Da Costa, an astronomer at the Australian National University (ANU), stated that the star is moving so fast that it will leave the Milky Way in about 100 million years and never return.
“We have traced the journey of this star to the center of our galaxy, which is quite exciting” said Da Costa. “S5-HVS1 travels at 6 million km/h and travels at a record speed of 6 million km/h. About 10 times faster than most of the stars in the Milky Way, including our Sun.” In astronomical terms, the star will leave our galaxy quite soon and will likely travel in intergalactic space for eternity. “It’s great to confirm a 30-year-old prediction. According to this prediction, stars can be thrown out of a galaxy by the supermassive black hole at its center”.
Professor Da Costa and his colleagues at ANU, Dr. Dougal Mackey and Dr. Thomas Nordlander, were involved in the study (ref.), conducted by Dr. Sergey Koposov of Carnegie Mellon University as part of the Southern Stellar Streams Spectroscopic Survey. The investigation involves astronomers from the Australian universities ANU, Macquarie University, University of Sydney and UNSW, as well as researchers from the United States, United Kingdom, and Chile. Dr. Ting Li from Princeton University leads the survey. Dr. Mackey stated that the team stumbled upon the rapidly moving star while searching for the remnants of small galaxies orbiting around the Milky Way.
“The star is only 29,000 light-years away, close enough by galactic standards, which means the team could measure its trajectory very accurately” said Dr. Mackey. Dr. Nordlander also clarified that supermassive black holes can launch stars by interacting with a binary star system, when two stars orbit each other. “If a binary system gets too close to a black hole, the black hole can capture one of the stars in a tight orbit and expel the other at a very high speed.”
ANU Siding Spring Observatory
The team discovered S5-HVS1 using the Anglo-Australian Telescope of 3.9 meters at the ANU Siding Spring Observatory. The 2dF instrument at the facility is the best in the world for studying thinly distributed stars in the periphery of the Milky Way. With its ability, simultaneous measurements can be obtained for a maximum of 400 targets at a time. Subsequent observations made with the ANU 2.3 meter telescope played an important role in confirming the extreme speed of the star.