University of Iowa astronomers say they’ve have found a giant star orbiting a black hole near a distant galaxy called M-82. Philip Kaaret, a U-of-I physics and astronomy professor, says it took many weeks of patient research to determine what it was they were seeing.
Kaaret says they used a NASA X-ray telescope that’s mounted on a satellite orbiting the Earth. He and a team of U-of-I students and faculty observed every other day for eight months, measuring X-rays coming from the black hole in that galaxy. He says “We discovered the X-rays from the black hole get repeatedly brighter and dimmer every 62 days. This told us the companion star orbiting around the black hole makes one orbit every 62 days. This, in turn, told us the companion star has to be a giant star.” Black holes are formed by the collapse of stars and even light cannot escape their very strong gravitational pull.
Kaaret says the star they’ve been watching was the key to the discovery. He says gas is being pulled off the star and as it falls into the black hole, it gets extremely hot, so hot it makes X-rays much like you’d get in the dentist’s office. Eventually, the star will be completely consumed by the black hole as all of its gases are sucked off into the black hole. Kaaret says it’s not likely there are any planets still orbiting that star.
He says it’s a giant star and the gravity of the black hole is so strong that it can pull matter right off the surface and if there had been any planets orbiting the star, they would have already been pulled off into the black hole. While black holes are the subject of much debate in the scientific community, Kaaret says it appears this particular hole is about one-thousand times larger than our solar system’s sun. The U-of-I research is being published in the latest issue of Science Express, the online version of the journal Science.