Hobby-Eberly Telescope Finds Three planets - each orbiting its own giant, dying star

Three planets - each orbiting its own giant, dying star - have been discovered by an international research team led by Alex Wolszczan, an Evan Pugh Professor of Astronomy and Astrophysics at Penn State, using the Hobby-Eberly Telescope.

Penn State is a major partner in the design, construciton, and operation of this telescope, which is one of the largest in the world. In 1992, Wolszczan became the first astronomer ever to discover planets outside our solar system. 

Credit: Marty Harris/McDonald Obs./UT-Austin

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 behavior of dying stars.

 

The research will be published in December in the Astrophysical Journal. The first author of the paper is Sara Gettel, a graduate student from Penn State's Department of Astronomy and Astrophysics, and the paper is co-authored by three graduate students from Poland.

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.