The nature of the symbiotic candidate 2MASS J07363415+6538548 in the field of NGC 2403

TL;DR

This study used multi-wavelength data and precise measurements to determine that the object 2MASS J07363415+6538548, initially thought to be a symbiotic star or cataclysmic variable, is actually a young active K-type dwarf star located 415 parsecs away.

Contribution

The paper provides a comprehensive multi-survey analysis that reclassifies a candidate symbiotic star as a young active K-type dwarf, clarifying its nature with detailed physical parameters.

Findings

The object is a young K-type dwarf star, not a symbiotic or cataclysmic variable.

It is located at 415 parsecs with a temperature of 4275 K.

The star exhibits strong X-ray emission and a rotational period of about 3 days.

Abstract

New Online Database of Symbiotic Variables includes several poorly characterised objects and candidate symbiotic stars, not only in the Milky Way but also in other galaxies. The goal of the research presented in this paper was to reveal the nature of 2MASS J07363415+6538548, the object discovered as an X-ray source in the field of NGC 2403, and tentatively classified as a symbiotic candidate or a cataclysmic variable. By analysis of available photometric data from ground-based surveys, together with high precision photometry from TESS, remarkable astrometric measurements of the Gaia satellite, and observations of other surveys spanning from X-rays to infrared, we have found that the object is not a symbiotic star nor a cataclysmic variable but rather an active K-type dwarf. The star is located in the distance of 415 pc, has an effective temperature of 4 275 K, luminosity of 0.14 L$\odot$, a mass of 0.7 M$\odot$, and radius of 0.7 R$\odot$. It has a rotational period ~ 3 days and is a strong X-ray source with the X-ray luminosity of ~ $10^{30}$ erg/s. Gyrochronology and isochrone fitting confirmed that the star is young.