To all the astronomy and star gazing enthusiast’s out there, we have something to rejoice, the closest ever black hole to earth (period) is found and it provides a whole different perspective of black holes in milkyway galaxy. A team of astronomers from the European Southern Observatory (ESO) and other institutes has discovered a black hole lying just 1000 light-years from Earth. The black hole is closer to our Solar System than any other found till date and forms part of a triple system that can be seen with the naked eye. The team found evidence for the invisible object by tracking its two companion stars using the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. They say this system could just be the tip of the iceberg, as many more similar black holes could be found in the future.
"We were totally surprised when we realized that this is the first stellar system with a black hole that can be seen with the unaided eye," says Petr Hadrava, Emeritus Scientist at the Academy of Sciences of the Czech Republic in Prague and co-author of the research.
Dietrich Baade, Emeritus Astronomer at ESO in Garching and co-author of the study, says: "The observations needed to determine the period of 40 days had to be spread over several months. This was only possible thanks to ESO's pioneering service-observing scheme under which observations are made by ESO staff on behalf of the scientists needing them."
The team initially observed a system, called HR 6819. The observations with the FEROS spectrograph on the MPG/ESO 2.2-metre telescope at La Silla showed that one of the two visible stars orbits an unseen object every 40 days. The hidden black hole in HR 6819 is one of the very first stellar-mass black holes found, that do not interact violently with their environment and therefore, appear truly black. But the team could spot its presence and calculate its mass by studying the orbit of the star in the inner pair. "An invisible object with a mass at least 4 times that of the Sun can only be a black hole," concludes Rivinius a team member based in European Southern Observatory, Santiago, Chile.
Astronomers have spotted only a couple of dozen black holes in our galaxy till this date, nearly all of which interact strongly with its environment and their presence is detected by the powerful X-rays in released by them. But scientists estimate that, over the Milky Way's lifetime, many more stars collapsed into black holes as they ended their lives. The discovery of this silent, invisible black hole in HR 6819 provides clues and insights about where the many hidden black holes in the Milky Way might be. "There must be hundreds of millions of black holes out there, but we know about only very few. Knowing what to look for should put us in a better position to find them. By finding and studying them we can learn a lot about the formation and evolution of those rare stars that begin their lives with more than about 8 times the mass of the Sun and end them in a supernova explosion that leaves behind a black hole.
The team is composed of Th. Rivinius (ESO, Santiago, Chile), D. Baade (ESO, Garching, Germany), P. Hadrava (Astronomical Institute, Academy of Science of the Czech Republic, Prague, Czech Republic), M. Heida (ESO Germany), and R. Klement (The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, USA).
Superb article!!!