A new study has revealed that the ancient RR Lyrae stars may not be as lonely as previously thought.
Many, perhaps most, stars in the Universe live their lives with companions by their sides, in so-called binary systems. Until recently, however, the ancient RR Lyrae stars appeared, for mysterious reasons, to live their lives all alone. But a recent study led by Chilean astronomers refuted the theory.
This apparent solitude has always intrigued astronomers. Now, however, an international research team led by experts of the Millennium Institute of Astrophysics (MAS) and the Pontificia Universidad Catolica de Chile's Institute of Astrophysics (IA-PUC) have found evidence that these stars may not abhor companionship so thoroughly after all.
The team reported on the identification of as many as 20 candidates RR Lyrae binaries - an increase of up to 2000 percent with respect to previous tallies. Twelve of those candidates have enough measurements to conclude with high confidence that they do indeed consist of two stars orbiting each other.
The authors used a method that astronomers call the "light-travel time effect," which exploits subtle differences in the time it takes starlight to reach Earth.
Indeed, the systems detected by Hajdu et al. have orbital periods of several years, which indicated that the companions, though bound together by gravity, are not very close to one another.
For co-author Marcio Catelan, MAS Associate Researcher, IA-PUC astrophysicist and Hajdu's thesis advisor, these results have significant implications for astrophysics.
The research is published in Monthly Notices of the Royal Astronomical Society Letters.