In the violent heart of our Milky Way galaxy lies a supermassive black hole with a mass equivalent to four million suns. But although the gravitational maw gobbles up anything that gets too close, it can also set up conditions that allow for the birth of new stars just a few light years away, according to a new study. Lead researcher Elizabeth Humphreys says the results, which uncovered what appear to be two young stars as close as seven light-years from the galactic center, were surprising, as that is “one of the last places … you would expect to find stars forming” [Scientific American].
Gas clouds that approach a black hole are usually ripped apart by the intense gravitational forces, but the new finding suggests that the molecular gas at the center of the Milky Way from which the stars form is denser than previously thought. The higher density gas makes it easier for the self-gravity of the condensing cloud to overcome the strong pull of the black hole and to collapse to form new stars [SPACE.com].
Researchers had previously spotted stars in the tumultuous neighborhood around our galaxy’s black hole, but they weren’t sure whether the stars were formed there or whether they had been drawn in towards the black hole after forming. Now it seems clear that stars are being born there in the galactic center, says lead researcher Elizabeth Humphreys: “We literally caught these stars in the act of forming” [SPACE.com]. The researchers detected the two young stars by using the Very Large Array of radio telescopes to search for radio signals called water masers that are associated with star birth.
The results, which were announced at the ongoing meeting of the American Astronomical Society, may indicate that astronomers have been too conservative in their estimations of where stars can form. Astronomer Q. Daniel Wang says the work offers a great example of how the peculiarities of the environment can allow stars to form where they might not be expected. What appears to be happening in the galactic center, he says, is a tug of war between gas clouds and the black hole in which some of the clouds “come out as winners” [ScienceNOW Daily News].
Bad Astronomy: Black holes don’t eat baby stars has more on this discovery
DISCOVER: Black Holes Birth Baby Stars
80beats: Confirmed: Monstrous Black Hole Lurks in Our Galaxy’s Center
Image: NASA, ESA, and A. Schaller (for STScI)