Pulsations and period changes of the non-Blazhko RR lyrae variable Y oct observed from Dome A, Antarctica

Journal Article · Thu Jan 01 04:00:00 EST 2015 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/149/1/25· OSTI ID:22342159

Zhihua, Huang; Jianning, Fu; Weikai, Zong; Lingzhi, Wang; Zonghong, Zhu ^[1]; M, Macri Lucas; Lifan, Wang ^[2]; Ashley, Michael C. B.; S, Lawrence Jon; Daniel, Luong-Van ^[3]; Xiangqun, Cui; Long-Long, Feng; Xuefei, Gong; Qiang, Liu; Huigen, Yang; Xiangyan, Yuan; Xu, Zhou; Zhenxi, Zhu ^[4]; R, Pennypacker Carl ^[5]

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1. Department of Astronomy, Beijing Normal University, Beijing 100875 (China)
2. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX (United States)
3. School of Physics, University of New South Wales, NSW (Australia)
4. Chinese Center for Antarctic Astronomy, Nanjing (China)
5. Center for Astrophysics, Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

During the operation of the Chinese Small Telescope Array (CSTAR) in Dome A of Antarctica in the years 2008, 2009, and 2010, large amounts of photometric data have been obtained for variable stars in the CSTAR field. We present here the study of one of six RR Lyrae variables, Y Oct, observed with CSTAR in Dome A, Antarctica. Photometric data in the i band were obtained in 2008 and 2010, with a duty cycle (defined as the fraction of time representing scientifically available data to CSTAR observation time) of about 44% and 52%, respectively. In 2009, photometric data in the g and r bands were gathered for this star, with a duty cycle of 65% and 60%, respectively. Fourier analysis of the data in the three bands only shows the fundamental frequency and its harmonics, which is characteristic of the non-Blazhko RR Lyrae variables. Values of the fundamental frequency and the amplitudes, as well as the total pulsation amplitude, are obtained from the data in the three bands separately. The amplitude of the fundamental frequency and the total pulsation amplitude in the g band are the largest, and those in the i band the smallest. Two-hundred fifty-one times of maximum are obtained from the three seasons of data, which are analyzed together with 38 maximum times provided in the GEOS RR Lyrae database. A period change rate of −0.96 ± 0.07 days Myr{sup −1} is then obtained, which is a surprisingly large negative value. Based on relations available in the literature, the following physical parameters are derived: [Fe/H] = −1.41 ± 0.14, M{sub V} = 0.696 ± 0.014 mag, V−K = 1.182 ± 0.028 mag, logT{sub eff} = 3.802 ± 0.003 K, logg = 2.705 ± 0.004, logL/L{sub ⊙} = 1.625 ± 0.013, and logM/M{sub ⊙} = −0.240 ± 0.019.

• OSTI ID: 22342159
• Journal Information: Astronomical Journal (New York, N.Y. Online), Journal Name: Astronomical Journal (New York, N.Y. Online) Journal Issue: 1 Vol. 149; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AMPLITUDES
ANTARCTICA
DATA
FOURIER ANALYSIS
HARMONICS
OPERATION
PHOTOMETRY
PULSATIONS
SEASONS
TELESCOPES
VARIABLE STARS