What began as a project to search for objects close to the sun yielded the discovery of the third-closest star system to it.
Penn State Associate Professor of Astronomy and Astrophysics Kevin Luhman discovered a pair of binary stars that are the third-closest star system to the sun and the closest star system discovered in almost a century, the Eberly College of Science announced in a press release.
The stars are brown dwarfs, which means they are cool and they don’t fuse hydrogen. The stars are orbiting each other and are similar in mass and size, Luhman said.
Sandy Leggett, a tenured astronomer at Gemini Observatory, said via email the Gemini South telescope on Cerro Pachón in Chile contributed to the interpretation of this “super-close object” by obtaining a spectrum of it.
By looking at a high quality image, it became clear there were two stars instead of one object orbiting the other “with a separation only three times that of the distance between the earth and the sun,” she said.
These brown dwarfs are 6.5 light years away, Luhman said.
People have been looking for close stars for 100 years, he said, though they believed everything had been found.
The star system is named WISE J104915.57-531906, because the discovery was made using a map of the entire sky, the release said. A NASA satellite called WISE (Wide-Field Infrared Survey Explorer) obtained the map of the sky. Each part of the sky was mapped multiple times to create time lapse images, Luhman said.
“WISE observed a given spot on the sky about twelve times during a day and a half, then repeated this pattern every six months,” Edward (Ned) Wright, principal investigator of the WISE mission and David S. Saxon Presidential Chair in Physics and professor of physics and astronomy at UCLA said via email.
Using these maps of the sky, Luhman could search for points of light that were moving rapidly across the sky, which indicates that these objects are close. He said he developed a computer program that searched the catalogue of data for points of light that seemed to be moving rapidly.
“Luhman found that the WISE source WISE 1049-5319 had moved quite a bit, which indicated it was quite nearby. He then backtracked the motion and found observations done in 1999, 1992 and 1978 that showed the same star in very different positions, confirming that the motion seen in the WISE data was real,” Wright said.
Now that Luhman found the star system, his next course of action will be to search for planets.
“One of the most exciting things in astronomy is searching for planets around other stars,” he said.
