CAOSP abstracts, Volume: 55, No.: 3, year: 2025

Author(s): Masuda, K.; Hirano, T.; Tomoyoshi, M.
Journal: Contributions of the Astronomical Observatory Skalnaté Pleso, vol. 55, no. 3, p. 346-351.
Date: 04/2025
Title: Weighing single-lined spectroscopic binaries using tidal RVs: the case of V723 Mon
Keyword(s): Radial velocity, Red giant stars, Tidal distortion
Pages: 346 -- 351
DOI: https://doi.org/10.31577/caosp.2025.55.3.346
NASA ADS Abstract Service: 2025CoSka..55c.346M
Citation:
License: This work is licensed under a Creative Commons Attribution 4.0 International License

Abstract: The tidal deformation of a star in a close binary not only produces the photometric flux variations (ellipsoidal variations, ELVs) but also causes the apparent radial velocity (RV) variations due to asymmetric distortion of the absorption lines. This ``tidal RV'' signal contains information equivalent to that from photometric ELVs, enabling its use in mass estimation for single-lined spectroscopic binaries (SB1s) and offering a potentially more robust approach against contaminating light relative to ELVs. In this work, we develop a quantitative model for the tidal RV signal and apply it to the binary system V723 Monocerotis, where both ELV and tidal RV signals are detected, and successfully determine the component masses using only the primary star's absorption lines. The masses derived from the tidal RV modeling show a reasonable agreement with those from an analysis based on ELVs that carefully accounts for the flux contamination from the secondary star. This result demonstrates that tidal RVs provide a useful alternative means for mass estimation in SB1s.