Exploring the physical properties of the γ Dor binary star RX Dra with photometry and asteroseismology

• Published in: New astronomy 2024-10, Vol.111, p.102234, Article 102234
• Main Authors: Li, Ping, Liao, Wen-Ping, Zeng, Qi-Huan, Sun, Qi-Bin, Li, Min-Yu
• Format: Article
• Language: English
• Subjects: Binaries: Eclipsing; Individual: RX Draconis; Stars: Fundamental parameters
• ISSN: 1384-1076; 1384-1092
• DOI: 10.1016/j.newast.2024.102234

We model the TESS light curve of the binary system RX Dra, and also first calculate a lot of theoretical models to fit the g-mode frequencies previously detected from the TESS series of this system. The mass ratio is determined to be q=0.9026−0.0032+0.0032. We newly found that there are 16 frequencies (F1–F7, F11–F20) identified as dipole g-modes, two frequencies (F21, F22) identified as quadrupole g-modes, and another two frequencies (F23, F24) identified as g-sextupole modes, based on these model fits. The primary star is newly determined to be a γ Dor pulsator in the main-sequence stage with a rotation period of about 5.7−0.2+0.7 days, rotating slower than the orbital motion. The fundamental parameters of two components are firstly estimated as follows: M1=1.53−0.17+0.00 M ⊙, M2= 1.38−0.00+0.18 M ⊙, T1=7240−44+490 K, T2=6747−221+201 K, R1=1.8288−0.0959+0.0260 R ⊙, R2= 1.3075−0.2543+0.0450 R ⊙, L1=8.2830−0.6036+1.8015 L ⊙ and L2= 3.4145−0.1843+0.1320 L ⊙. Our results show that the secondary star is in the solar-like pulsator region of the H–R diagram, indicating that it could be a pulsating star of this type. Finally, the radius of the convective core of the primary star is estimated to be about 0.1403−0.0000+0.0206 R ⊙. •RX Dra is a total eclipse binary system.•The physical parameters of RX Dra are determined for the first time.•The primary star of is detected as a γ Dor pulsating star and the secondary star as a possible solar-like pulsating star.•The pulsating modes of 20 frequencies of the primary star are identified for the first time in this work.