New Symbiotic Stars from LAMOST DR10 Spectra and Multi-band Photometry

TL;DR

This study identified nine symbiotic stars from LAMOST DR10 spectra, including two new discoveries, and analyzed their properties using multi-band photometry and spectral energy distribution fitting to understand their accretion processes.

Contribution

The paper presents the first identification of two new symbiotic stars from LAMOST DR10 and characterizes their properties using multi-band data and SED fitting, expanding the known sample.

Findings

Two new symbiotic stars identified from LAMOST data.

Accreting-only symbiotic star candidates show similar accretion rates to confirmed systems.

Multi-band photometry confirms the nature of the candidates.

Abstract

Symbiotic star (SySt) is long-period interacting binary system, typically consisting of a white dwarf and a red giant surrounded by a nebula. These systems are natural astrophysical laboratories for investigating binary star evolution. In this paper, we identified nine SySts from the LAMOST DR10 low-resolution spectra survey, seven of which were previously known, while two are newly identified. Initially, we selected LAMOST spectra exhibiting typical SySt emission lines (e.g., $\rm H_{\alpha}, ~H_{\beta}, ~H_{\gamma}, ~and ~He II$). Subsequently, we utilized the distribution of known SySts on the HR diagram to select SySt candidates, and visually inspected their spectra. Ultimately, we classified all nine as S-type SySts using the $J - H$ vs. $H - K$ diagram. Additionally, based on multi-band photometric data from GALEX, Gaia, 2MASS, ALLWISE, and several X-ray catalogs, we found 12 accreting-only SySt (acc-SySt) candidates, characterized by concurrent ultraviolet and infrared excess and accretion process. Furthermore, we estimated the white dwarf temperatures by fitting their observed SEDs using a combination of Kurucz stellar atmosphere model and Koester white dwarf model. We compared the accretion rates of acc-SySt candidates and confirmed SySts, and found they have similar accretion rate distribution, providing evidence that these acc-SySt candidates constitute bona fide SySts.