Wide binaries with white dwarf or neutron star companions discovered from Gaia DR3 and LAMOST

TL;DR

This study combines Gaia DR3 and LAMOST data to discover three wide binaries likely containing compact objects such as white dwarfs or neutron stars, enhancing understanding of such systems in the Milky Way.

Contribution

It presents the first identification of wide binaries with potential compact companions using combined Gaia DR3 and LAMOST data, employing spectral and kinematic analysis.

Findings

Three candidate binaries with possible compact objects identified.

Most systems are located in the Milky Way's thin disk.

Spectral analysis suggests presence of white dwarf or neutron star companions.

Abstract

Gaia DR3 mission has identified and provided about 440,000 binary systems with orbital solutions, offering a valuable resource for searching binaries including a compact component. By combining the Gaia DR3 data with radial velocities (RVs) from the LAMOST spectroscopic survey, we identify three wide binaries possibly containing a compact object. For two of these sources with a main-sequence companion, no obvious excess is observed in the blue/red band of the Gaia DR3 XP spectra, and the LAMOST medium-resolution spectra exhibit clear single-lined features. The absence of an additional component from spectral disentangling analysis further suggests the presence of compact objects within these systems. On the other hand, the visible star of the third source is a stripped giant star. In contrast to most binaries including stripped stars, no emission line is detected in the optical spectra. The unseen star could potentially be a massive white dwarf or neutron star, but the possibility of an F-type dwarf star scenario cannot be ruled out. An examination of about ten binaries containing white dwarfs or neutron stars using both kinematic and chemical methods suggest most of these systems are located in the thin disk of the Milky Way.