2021/02/26 by Alaxendra Panchal, A. Panchal, Y. C. Joshi +1
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Asymmetry #Emission spectrum #LAMOST #Light curve #Photometry (optics) #Spectral analysis #Spectral line #Stellar, planetary, and galactic studies #Telescope #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/abea0c
Accepted for publication in Astronomical Journal
arxiv created 2021/02/26 · openalex created_date 2021/03/15 · openalex publication_date 2021/04/09 · arxiv updated 2021/04/21 · openalex updated_date 2026/08/05
Abstract We present the photometric and spectroscopic analysis of four W UMa binaries J015829.5+260333 (hereinafter as J0158), J030505.1+293443 (hereinafter as J0305), J102211.7+310022 (hereinafter as J1022), and KW Psc. The VR c I c band photometric observations are carried out with the 1.3 m Devasthal Fast Optical Telescope (DFOT). For low-resolution spectroscopy, we used the 2 m Himalayan Chandra Telescope (HCT) as well as the archival data from the 4 m LAMOST survey. The systems J0158 and J0305 show a period increase rate of 5.26( ± 1.72) × 10 −7 days yr −1 and 1.78( ± 1.52) × 10 −6 days yr −1 , respectively. The period of J1022 is found to be decreasing with a rate of 4.22 ( ± 1.67) × 10 −6 days yr −1 . The period analysis of KW Psc displays no change in its period. The PHOEBE package is used for the light-curve modeling and basic parameters are evaluated with the help of the GAIA parallax. The asymmetry of light curves is explained with the assumption of cool spots at specific positions on one of the components of the system. On the basis of temperatures, mass ratios, fill-out factors, and periods, the system J1022 is identified as a W-subtype system while the others show some mixed properties. To probe the chromospheric activities in these W UMa binaries, their spectra are compared with the known inactive stars’ spectra. The comparison shows emission in H α , H β , and Ca II . To understand the evolutionary status of these systems, the components are plotted in mass–radius and mass–luminosity planes with other well characterized binary systems. The secondary components of all the systems are away from ZAMS, which indicates that the secondary is more evolved than the primary component.