Binary Analysis and Period Study of the Long-Period, High Mass Ratio Contact Binary KIC 7766185

2025/07/20 by Larsen, Conor M, Prsa, Andrej
#FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR)

paper · doi:10.48550/arxiv.2507.14979

Abstract

We present an in-depth photometric and spectroscopic study of the contact binary KIC 7766185. Spectroscopic observations were conducted on the Mayall 4-m telescope at Kitt Peak National Observatory and used to extract radial velocities. Using the radial velocity measurements, Kepler photometry, and Gaia multi-color photometry, binary analysis was performed in PHOEBE to determine orbital and stellar parameters. The results classify KIC 7766185 as an A-type W UMa system and reveal one of the largest and most massive secondary stars in the sample of well studied W UMa systems. The two stars are in a shallow contact state, with a small fillout factor of 0.029±0.002. Along with the binary analysis, we conduct a period study that reveals evidence for a cyclic variation in the eclipse timings.

Citations

• Contact tracing of binary stars: Pathways to stellar mergers
• GaiaEarly Data Release 3
• emcee : The MCMC Hammer
• Structure and evolution of low-mass W Ursae Majoris type systems - II. With angular momentum loss
• New Grids of ATLAS9 Model Atmospheres

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