Astronomers solve decades-long mystery of the lonely old stars


A recent study led by Chilean astronomers shows that RR Lyrae stars may not be as lonely as previously thought.

The new research is published in Monthly Notices of the Royal Astronomical Society Letters.

Stars are very often found not in isolation, but rather in pairs. In these so-called binary systems, two stars orbit around their common centre of gravity, CBC news reported.

Suitable binary systems are of extreme importance in astrophysics, as their properties can be inferred with unparalleled accuracy from detailed analysis of their orbital properties.

Puzzlingly, however, an overwhelming majority of the known members of a very important family of stars, known to astronomers as RR Lyrae variables, have for long appeared to live their lives all alone.

These stars, being among the oldest known in the cosmos, contain precious information about the origin and evolution of the stellar systems that harbour them, such as the Milky Way itself.

However, the lack of RR Lyrae stars in binary systems has made a direct assessment of some of their key properties difficult. Most often, theory had to be invoked to fill the gap.

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 Cat¢lica de Chile’s Institute of Astrophysics (IA-PUC) have found evidence that these stars may not abhor companionship so thoroughly after all.