Photometric and Spectroscopic Observations of the Neglected Near-contact Binary Cl* Melotte 111 AV 1224. (20th August 2018)

• Record Type: Journal Article
• Authors: Fox-Machado, L.; Cang, T. Q.; Michel, R.; Fu, J. N.; Li, C. Q.
• Is Part Of: Publications of the Astronomical Society of the Pacific. Volume 130:Number 992(2018)
• Publication Date: 2018-08-20
• Subjects: binaries: eclipsing—stars: fundamental parameters—stars: individual: Cl* Melotte 111 AV 1224; Astronomy -- Periodicals; Astronomy; Periodicals; Periodicals; 520.5
• DOI: 10.1088/1538-3873/aad5d9
• Languages: English
• ISSNs: 0004-6280

Abstract

Abstract: This paper presents a photometric and spectroscopic study of the short-period binary star Cl* Melotte 111 AV 1224. Measurements in the B, V, and R passbands obtained during three observing runs between 2014 and 2017 and medium-resolution spectra secured in 2014, are analyzed together with public data from the SuperWASP and LAMOST projects. Our light curves show marked asymmetry with a variable O'Connell effect. The SuperWASP photometry is used to derive a mean binary period of 0.345225 days. The analysis of the ( O − C ) diagram reveals that the orbital period is decreasing at a rate of dP / dt = −3.87 × 10 −6 days yr −1, which may be caused by mass transfer from the more-massive component to the less-massive one. The system is found to be a single-lined spectroscopic binary with a systemic velocity, γ = 1 ± 3 Km s −1, and a semi-amplitude, K1 = 21 ± 5 Km s −1 . The spectral classification and the effective temperature of the primary component are estimated to be K0V ± 1 and 5200 ± 150 K, respectively. The photometric and spectroscopic solutions reveal that Cl* Melotte 111 AV 1224 is a low-mass ratio ( q = m 2 / m 1 ∼ 0.11), low-inclination (∼38°), near-contact system. The masses, radii, and luminosity for the primary and secondary are estimated to be 1.02 ± 0.06 M ⊙, 1.23 ± 0.05 R ⊙, 1.01 ± 0.06 L ⊙, and 0.11 ± 0.08 M ⊙, 0.45 ± 0.05 R ⊙, 0.10 ± 0.06 L ⊙, respectively. The marginal contact, together with the period decrease, suggests that this binary system may be at a key evolutionary stage, as predicted by the theory of thermal relaxation oscillations.