TYC 8380-1953-1: Discovery of an RS CVn binary through the XMM-Newton slew survey

TL;DR

This paper reports the discovery of an RS CVn binary star system via the XMM-Newton slew survey, including optical and X-ray follow-up that characterizes its binary nature, spectral type, and high X-ray luminosity.

Contribution

The paper presents the first identification of TYC 8380-1953-1 as an RS CVn binary through XMM-Newton data and follow-up observations, highlighting its high X-ray luminosity and binary properties.

Findings

TYC 8380-1953-1 is a double-lined spectroscopic binary.

Both components are likely K0/2+K3/5 spectral types.

The system has a high X-ray luminosity exceeding 4 x 10^31 erg/s.

Abstract

In this paper we report the discovery of the chromospherically active (RS CVn type) binary TYC 8380-1953-1 through the XMM-Newton slew survey and present results of our optical and X-ray follow-up. With a flux limit of $6 \times 10^{-13}$ erg cm$^{-2}$ s$^{-1}$ in the soft band ($0.2 - 2$ keV), the XMM-Newton slew has a similar sensitivity to the ROSAT All Sky Survey allowing interesting sources to be identified by their long-term variability. Two different types of stellar sources are detected in shallow X-ray surveys: young stars (both pre-main and main sequence stars) and chromospherically active binaries (BY Dra and RS CVn type systems). The discovery of stars in such surveys and the study of their nature through optical follow-ups is valuable to determine their spatial distribution and scale height in the Galaxy. Our analysis shows that TYC 8380-1953-1 is a double-lined spectroscopic binary with both components having similar spectral type (likely K0/2+K3/5) and luminosity. With a typical coronal temperature for an RS CVn system ($kT \sim 1.15$ keV) and an X-ray luminosity in the $0.3-10$ keV energy band higher than $4 \times 10^{31}$ erg\,s$^{-1}$, TYC 8380-1953-1 lies among the most X-ray luminous RS CVn binaries.