Mass Transfer and Loss in an Extremely Low-mass-ratio Semidetached Binary with a Pulsating A-type Star
Year: 2026
Type: article
Abstract: AY Gem is a short-period Algol-type eclipsing binary with a period of 3.05 days that is neglected for spectroscopic and photometric investigations. The first radial-velocity curves have been obtained for AY Gem by using LAMOST medium- and low-resolution spectra together with the BFOSC spectral data observed with the 2.16 m telescope in Xinglong station. It is detected that AY Gem is a double-lined spectroscopic binary with an extremely low mass ratio of q = 0.10 ± 0.02. Photometric solutions derived by using the TESS data reveal that it is a semidetached binary, and the absolute parameters were determined to be: M 1 = 2.02 ± 0.05 M ⊙ , M 2 = 0.19 ± 0.02 M ⊙ ; R 1 = 1.91 ± 0.03 R ⊙ , R 2 = 2.37 ± 0.07 R ⊙ . By analyzing the O–C diagram, it is found that the orbital period is decreasing continuously, which can be explained as nonconservative mass transfer with a mass-loss rate of M ̇ ∼ − 1 0 − 9 M ⊙ · yr − 1 . Meanwhile, it is discovered that AY Gem exhibits a distinct double-peaked H α emission line, indicating the presence of a transient disk. This is further supported by the measurement of the equivalent width and the q – r diagram. Furthermore, the primary component is identified as a δ Scuti-type star that pulsates at f 18 = 11.29511 days −1 and f 19 = 11.37374 days −1 . These results suggest that AY Gem is a good astrophysical laboratory for investigating mass transfer and loss, binary evolution, and the effect of tidal forces and mass accretion on stellar pulsations.
Source: The Astrophysical Journal
Authors: Hui-Ting Zhang, Sheng-Bang Qian, Wen-Ping Liao
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funders: National Science Foundation, Smithsonian Institution, National Aeronautics and Space Administration, Space Telescope Science Institute, National Natural Science Foundation of China, Chinese Academy of Sciences, Yunnan University, National Development and Reform Commission, Science Mission Directorate, National Astronomical Observatories, Chinese Academy of Sciences
OpenAlex ID: W7122642790