Long-term Photometric and Low-resolution Spectroscopic Analysis of Five Contact Binaries

Abstract

A photometric and spectroscopic investigation is performed on five W Ursae Majoris eclipsing binaries J015818.6+260247 (hereinafter as J0158b), J073248.4+405538 (hereinafter as J0732), J101330.8+494846 (hereinafter as J1013), J132439.8+130747 (hereinafter as J1324), and J152450.7+245943 (hereinafter as J1524). The photometric data are collected with the help of the 1.3 m Devasthal Fast Optical Telescope, the 1.04 m Sampurnanand Telescope, and the Transiting Exoplanet Survey Satellite space mission. The low-resolution spectra of the 4 m Large Sky Area Multi-Object Fiber Spectroscopic Telescope are used for spectroscopic analysis. The orbital period change of these systems is determined using our photometric data and previously available photometric data from different surveys. The orbital period of J1013 and J1524 is changing at a rate of −2.552 (±0.249) × 10−7 days yr−1 and −6.792( ±0.952) × 10−8 days yr−1, respectively, while others do not show any orbital period change. The orbital period change of J1013 and J1524 corresponds to a mass transfer rate of 2.199 × 10−7 and 6.151 × 10−8 M ⊙ yr−1 from the primary to the secondary component in these systems. It is likely that angular momentum loss via magnetic braking may also be responsible for the observed orbital period change in the case of J1524. All systems have a mass ratio lower than 0.5, except J0158b with a mass ratio of 0.71. All the systems are shallow-type contact binaries. J0158b and J1524 are subtype A while others are subtype W. The H α emission line region is compared with template spectra prepared using two inactive stars with the help of the STARMOD program. The J0158, J1324, and J1524 systems show excess emission in the residual spectra after subtraction of the template.

A Study of Six Extreme Low Mass Ratio Contact Binary Systems

“…From Table 4 we see that in all cases except A2003, where the variation between SED and spectral effective temperature varies by more than 500 K, there is good agreement between a collective photometric approach and spectral class for estimating the effective temperature. The findings are very similar to Panchal et al (2022) who also found close agreement between spectral class effective temperature and SED modeled values. The difference in A2003 most likely, although not for certain, relates to the relative high extinction for the system with an estimated distance corrected extinction of 0.48 magnitudes.…”

Extremely Low Mass Ratio Contact Binaries. I. The First Photometric and Spectroscopic Investigations of Ten Systems

“…Second, all the spectra were normalized and removed cosmic rays. Third, the STARMOD code developed by Barden (1985; which has been used by many researchers; e.g., Zhang et al 2020;Panchal & Joshi 2021;Panchal et al 2022) was applied to produce the synthetic spectra of the two inactive stars by considering the radial velocity shift, the rotationally broadening, and the weight of the two stars. Finally, the subtracted spectra between the synthetic spectra and the LAMOST spectra were obtained and displayed in Figure 5 (the H α line region is shown).…”

Period Investigation on Two W UMa Binaries HH UMa and V1175 Her

“…Long term changes of the orbital period in contact binary systems are very common phenomena. According to the investigations, the period of a contact binary is not constant in many cases (Qian 2001;Qian et al 2007;Xiao et al 2016;Yang et al 2022aYang et al , 2022bPanchal et al 2022;Gao et al 2022;Hu et al 2022;Xu et al 2022). However, there are also cases with unchanged periods, such as LQ Com (Hu et al 2022) and PZ UMa (Zhou & Soonthornthum 2019).…”