New triple systems in the RasTyc sample of stellar X-ray sources

TL;DR

This paper reports the discovery and analysis of three new hierarchical triple star systems with short-period inner binaries, providing detailed orbital and stellar parameters, and indicating their youth and stability.

Contribution

It introduces the identification and detailed characterization of three new spectroscopic triple systems using high-resolution observations and synthetic spectral analysis.

Findings

All systems are composed of main sequence stars.

The systems are stable hierarchical triples.

They are relatively young based on kinematics and Lithium content.

Abstract

During the study of a large set of late-type stellar X-ray sources, we discovered a large fraction of multiple systems. In this paper we investigate the orbital elements and kinematic properties of three new spectroscopic triple systems as well as spectral types and astrophysical parameters (T_eff, log g, vsin i, log N(Li)) of their components. We conducted follow-up optical observations, both photometric and spectroscopic at high resolution, of these systems. We used a synthetic approach and the cross-correlation method to derive most of the stellar parameters. We estimated reliable radial velocities and deduced the orbital elements of the inner binaries. The comparison of the observed spectra with synthetic composite ones, obtained as the weighted sum of three spectra of non-active reference stars, allowed us to determine the stellar parameters for each component of these systems. We found all are only composed of main sequence stars. These three systems are certainly stable hierarchical triples composed of short-period inner binaries plus a tertiary component in a long-period orbit. From their kinematics and/or Lithium content, these systems result to be fairly young.