Double-lined Spectroscopic Binary Stars in the Radial Velocity Experiment Survey

TL;DR

This paper introduces a new method for detecting double-lined spectroscopic binary stars in large spectral surveys, demonstrating high recovery rates and identifying numerous candidates, including rare and complex systems.

Contribution

A novel detection technique based on cross-correlation function analysis that effectively identifies binary stars in survey data, with potential application to Gaia data.

Findings

Recovered ~80% of binaries with ~1 day periods

Identified 123 binary candidates in RAVE data

Detected complex systems including a triple star

Abstract

We devise a new method for the detection of double-lined binary stars in a sample of the Radial Velocity Experiment (RAVE) survey spectra. The method is both tested against extensive simulations based on synthetic spectra, and compared to direct visual inspection of all RAVE spectra. It is based on the properties and shape of the cross-correlation function, and is able to recover ~80% of all binaries with an orbital period of order 1 day. Systems with periods up to 1 year are still within the detection reach. We have applied the method to 25,850 spectra of the RAVE second data release and found 123 double-lined binary candidates, only eight of which are already marked as binaries in the SIMBAD database. Among the candidates, there are seven that show spectral features consistent with the RS CVn type (solar type with active chromosphere) and seven that might be of W UMa type (over-contact binaries). One star, HD 101167, seems to be a triple system composed of three nearly identical G-type dwarfs. The tested classification method could also be applicable to the data of the upcoming Gaia mission.