Three planets — each orbiting its own giant, dying star — have been discovered by an international research team led by a Penn State University astronomer.
Using the Hobby-Eberly Telescope, astronomers observed the planets’ parent stars — called HD 240237, BD +48 738, and HD 96127 — tens of light years away from our solar system. One of the massive, dying stars has an additional mystery object orbiting it, according to team leader Alex Wolszczan, an Evan Pugh Professor of Astronomy and Astrophysics at Penn State, who, in 1992, became the first astronomer ever to discover planets outside our solar system. The new research is expected to shed light on the evolution of planetary systems around dying stars. It also will help astronomers to understand how metal content influences the behaviour of dying stars.
The three newly-discovered planetary systems are more evolved than our own solar system. “Each of the three stars is swelling and has already become a red giant — a dying star that soon will gobble up any planet that happens to be orbiting too close to it,” Wolszczan said. “While we certainly can expect a similar fate for our own Sun, which eventually will become a red giant and possibly will consume our Earth, we won’t have to worry about it happening for another five-billion years.” Wolszczan also said that one of the massive, dying stars — BD +48 738 — is accompanied not only by an enormous, Jupiter-like planet, but also by a second, mystery object. According to the team, this object could be another planet, a low-mass star, or — most interestingly — a brown dwarf, which is a star-like body that is intermediate in mass between the coolest stars and giant planets. “We will continue to watch this strange object and, in a few more years, we hope to be able to reveal its identity,” Wolszczan said.