Compact Object Candidates with K/M-dwarf Companions from LAMOST Low-resolution Survey

Abstract

Searching for compact objects (black holes, neutron stars, or white dwarfs) in the Milky Way is essential for understanding the stellar evolution history, the physics of compact objects, and the structure of our Galaxy. Compact objects in binaries with a luminous stellar companion are perfect targets for optical observations. Candidate compact objects can be achieved by monitoring the radial velocities of the companion star. However, most of the spectroscopic telescopes usually obtain stellar spectra at a relatively low efficiency, which makes a sky survey for millions of stars practically impossible. The efficiency of a large-scale spectroscopic survey, the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST), presents a specific opportunity to search for compact object candidates, i.e., simply from the spectroscopic observations. Late-type K/M stars are the most abundant populations in our Galaxy. Owing to the relatively large Keplerian velocities in the close binaries with a K/M-dwarf companion, a hidden compact object could be discovered and followed-up more easily. In this study, compact object candidates with K/M-dwarf companions are investigated with the LAMOST low-resolution stellar spectra. Based on the LAMOST Data Release 5, we obtained a sample of $56$ binaries, each containing a K/M-dwarf with a large radial velocity variation $\Delta V_{\mathrm{R}}>150{\mathrm{km}\mathrm{s}}^{-1}$. Complemented with the photometric information from the Transiting Exoplanet Survey Satellite, we derived a sample of $35$ compact object candidates, among which, the orbital periods of $16$ sources were revealed by the light curves. Considering two sources as examples, we confirmed that a compact object existed in the two systems by fitting the radial velocity curve. This study demonstrates the principle and the power of searching for compact objects through LAMOST.

20 pages, 7 figures, 4 tables, Science China Physics, Mechanics & Astronomy, Vol.65 No.2:229711

References in corpus (13)

• The Transiting Exoplanet Survey Satellite
• X-ray Properties of Black-Hole Binaries
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Catalogue of high-mass X-ray binaries in the Galaxy ($4^{th}$ edition)
• A catalogue of low-mass X-ray binaries in the Galaxy, LMC, and SMC (Fourth edition)
• A wide star-black-hole binary system from radial-velocity measurements
• Signatures of unresolved binaries in stellar spectra: implications for spectral fitting
• Post Common Envelope Binaries from SDSS. V: Four eclipsing white dwarf main sequence binaries
• Population Synthesis of Black Hole Binaries with Normal-Star Companions: I. Detached Systems
• Fourteen new eclipsing white dwarf plus main-sequence binaries from the SDSS and Catalina surveys
• Classifying Single Stars and Spectroscopic Binaries Using Optical Stellar Templates
• A Method to Search for Black Hole Candidates with Giant Companions by LAMOST
• Mining for Candidates of Galactic Stellar-mass Black Hole Binaries with LAMOST

Cited by in corpus (5)

• A dynamically discovered and characterized non-accreting neutron star -- M dwarf binary candidate
• A long-period pre-ELM system discovered from LAMOST medium-resolution survey
• A White Dwarf-Main Sequence Binary Unveiled by Time-Domain Observations from LAMOST and TESS
• Searching for compact objects in binaries with Gaia DR3
• Searching for Compact Object Candidates from LAMOST Time-Domain Survey of Four K2 Plates