Stellar multiplicity across the mass spectrum

E-ISSN： 1638-1963|64|issue|155-162

ISSN： 1633-4760

Source： EAS Publications Series, Vol.64, Iss.issue, 2014-02, pp. : 155-162

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

We investigate the multiplicity as a function of stellar mass. For this purpose we have created three complete samples of O, B, and FGK stars and performed multi-epoch, high-resolution (R ∼ 50 000) optical spectroscopy. The current results for the O-type stars suggest a multiplicity fraction of more than 80%. Many O-type systems contain components of similar mass. The multiplicity fraction for B stars seems to decrease from 70% to 20%. We argue that this general decrease is most likely due to observational biases; however, similar-mass systems – like common for O-type stars – seem to vanish toward later B-types. Within the sample of F stars we observe an increasing multiplicity fraction with primary mass (∼50% – 80%); simultaneously there is a decrease of single stars toward the A-type regime. Closer inspection of spectroscopic binaries – either by spectral disentangling or by common proper motion studies – reveals higher-level systems in each mass range.