Extremely low mass ratio contact binaries -- I. the first photometric and spectroscopic investigations of ten systems

Abstract

The photometric and spectroscopic investigations of ten contact binaries were presented for the first time. It is discovered that the mass ratios of all the ten targets are smaller than 0.15, they are extremely low mass ratio contact binaries. Seven of them are deep contact binaries, two are medium contact binaries, while only one is a shallow contact system. Five of them show O'Connell effect, and a dark spot on one of the two components can lead to a good fit of the asymmetric light curves. The orbital period studies of the ten binaries reveal that they all exhibit long-term period changes, six of them are increasing, while the others are shrinking. The LAMOST spectra were analyzed by the spectral subtraction method, and all the ten targets exhibit excess emissions in the H${}_{\alpha }$ line, indicating chromospheric activity. The evolutionary states of the two components of the ten binaries were studied, and it is found that their evolutionary states are identical to those of the other contact binaries. Based on the study of the relation between orbital angular momentum and total mass, we discovered the ten systems may be at the late evolutionary stage of a contact binary. The initial masses of the two components and the ages of them were obtained. By calculating the instability parameters, we found that the ten contact binaries are relatively stable at present.

19 pages, 8 figures,, and 9 tables, accepted by AJ

References in corpus (18)

• The Transiting Exoplanet Survey Satellite
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• The Zwicky Transient Facility: Data Processing, Products, and Archive
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• The first WASP public data release
• Physical Properties and Catalogue of EW-type Eclipsing Binaries Observed by LAMOST
• Stellar Mergers Are Common
• Dynamical evolution of active detached binaries on log Jo - log M diagram and contact binary formation
• The dynamical stability of W Ursae Majoris-type systems
• Self-consistent Stellar Radial Velocities from LAMOST Medium-Resolution Survey (MRS) DR7
• The short period end of the contact binary period distribution based on the All Sky Automated Survey (ASAS)
• Contact binaries at the short period cut-off I. statistics and the first photometric investigations of ten totally eclipsing systems
• On the minimum mass ratio of W UMa binaries
• Photometric and Spectroscopic analysis of four contact binaries
• Photometric and period investigation of the late F-type overcontact binary II UMa
• The first photometric and spectroscopic analysis of the extremely low mass ratio contact binary NSVS 5029961
• Long-term photometric and low-resolution spectroscopic analysis of five contact binaries

Cited by in corpus (3)

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• A Study of Six Extreme Low Mass Ratio Contact Binary Systems
• Photometric and Spectroscopic Study of Two Low Mass Ratio Contact Binary Systems: CRTS J225828.7-121122 and CRTS J030053.5+230139