ST Aqr: Photometric and orbital period analysis of a near-contact binary with a secularly decreasing period
New Astronomy, cilt.130, 2027 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 130
- Basım Tarihi: 2027
- Doi Numarası: 10.1016/j.newast.2026.102644
- Dergi Adı: New Astronomy
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, INSPEC, Academic Search Ultimate (EBSCO)
- Anahtar Kelimeler: Binaries, Eclipsing - stars, Fundamental parameters - stars, Individuals (ST aqr), Near-contact binaries - stars
- Hakkari Üniversitesi Adresli: Evet
Özet
Near contact binary (NCB) systems are astrophysically quite interesting; the light curve (LC) of ST Aqr, a member of this class, was obtained from the Transiting Exoplanet Survey Satellite (TESS) database and analyzed in detail in this article. A q-search was undertaken to determine the mass ratio (q=M2/M1) for ST Aqr, and the q was found to be 0.472 ± 0.009. It was showed that each body in the ST Aqr system is a NCB with a filling factor of approximately 99 percent. As accurate absolute parameters are essential for investigating the evolutionary properties of such systems, the body masses of ST Aqr were estimated as M1=1.81±0.10M⊙ and M2=0.85±0.06M⊙, while their corresponding radii were found to be R1=2.27±0.05R⊙ and R2=1.67±0.04R⊙. In the analysis of ST Aqr's orbital period (OP), a decrease in the period was detected, and this value was calculated to be 2.08 s per century. Since the bodies do not fill their Roche lobes, we believe that the decrease in OP cannot be explained by a conserved mass transfer between the bodies. For this reason, the observed orbital period decrease may be attributed to angular momentum loss (AML) from the system through magnetic braking associated with magnetic activity. The non-conservative mass transfer rate was calculated to be 1.64×10−7M⊙ per year. To better understand the nature of ST Aqr, it was plotted on the log Mtot–log J and Hertzsprung–Russell (HR) diagrams.