Discovery of 13 new symbiotic stars in Gaia DR3

ABSTRACT Symbiotic stars (SySts) are considered potential progenitors of Type Ia supernovae (SNe Ia). However, theoretical studies suggest that their contribution to the total number of SNe Ia rate is very small. The number of known SySts remains significantly lower, by orders of magnitude, than predicted by theory. Continued searches for new members are therefore essential to better constrain population synthesis models. In this study, we conduct a search for new potential SySts captured in Gaia’s observations. Optical photometric data from IPHAS and VPHAS+, infrared data from 2MASS and WISE, and ultraviolet data from GALEX are combined to uncover hidden members in the Gaia catalogue of 12.4 million variable sources. For sources lacking optical data, synthetic optical data are computed using the low-resolution Gaia BP/RP spectra in order to identify the H $\alpha$ emitters. By applying infrared and optical selection criteria, we identified 43 S-type and 11 D-type SySts that meet these requirements. Of these, 10 S-type and 3 D-type are considered highly probable candidates, while the remainder are already known members. Analysis of the Gaia BP/RP spectroscopic data confirms the presence of the H $\alpha$ emission line as well as molecular bands in all 13 systems, validating their classification as bona fide SySts. Systematic searches for SySts and other rare stellar groups, integrating data from multiple publicly available catalogues, are essential to uncover previously hidden members.