Photometry of Variable Stars From Dome A, Antarctica

Abstract

Dome A on the Antarctic plateau is likely one of the best observing sites on Earth thanks to the excellent atmospheric conditions present at the site during the long polar winter night. We present high-cadence time-series aperture photometry of 10,000 stars with i < 14.5 mag located in a 23 deg 2 region centered on the south celestial pole. The photometry was obtained with one of the CSTAR telescopes during 128 days of the 2008 Antarctic winter. We used this photometric data set to derive site statistics for Dome A and to search for variable stars. Thanks to the nearly uninterrupted synoptic coverage, we found six times as many variables as previous surveys with similar magnitude limits. We detected 157 variable stars, of which 55% were unclassified, 27% were likely binaries, and 17% were likely pulsating stars. The latter category includes δ Scuti, γ Doradus, and RR Lyrae variables. One variable may be a transiting exoplanet.

Variable Stars Observed in the Galactic Disk by AST3-1 from Dome A, Antarctica

“…The BLS method searches for signals characterized by a periodic alternation between two discrete levels with much less time spent at the lowlevel (occultation) phase. Similar methods (LS & BLS) for hunting for variable stars, were applied in Wang et al (2011Wang et al ( , 2013a; Yao et al (2015). Surveys such as OGLE II use the Detached Eclipsing Binary Light curve fitter (Devor 2005, hereinafter DEBiL) for finding and analyzing eclipsing binaries in large datasets.…”

“…The first optical telescope was called CSTAR (the Chinese Small Telescope ARray; Yuan et al 2008) with an effective aperture of 10 cm and field of view (FOV) of 20 deg 2 and was installed at Dome A in January 2008; CSTAR produced a 3-year photometric dataset, and a number of studies of stellar variability have been published (Zhou et al 2010a,b;Wang et al 2011Wang et al , 2012Zhou et al 2013;Wang et al 2013a,b;Meng et al 2013;Huang et al 2013;Fu et al 2014;Qian et al 2014;Wang et al 2014a,b;Zong et al 2015;Huang et al 2015;Wang et al 2015;Yang et al 2015;Oelkers et al 2015Oelkers et al , 2016Liang et al 2016). The second-generation of optical telescope at Dome A is called AST3, which in turn consists of three telescopes, each with an entrance pupil diameter of 0.5 m, and a FOV of 4.3 deg 2 Yuan & Su 2012;Yuan et al 2014Yuan et al , 2015.…”

DISCOVERY OF MULTIPLE PULSATIONS IN THE NEWδSCUTI STAR HD 92277: ASTEROSEISMOLOGY FROM DOME A, ANTARCTICA

“…We used the catalog of calibrated g, r, i, and z magnitudes of Tycho stars (Ofek 2008) for our photometric calibration, the same method used by Wang et al (2011). The selected stars in the range 7 < < g r [ , ] 12 mag and d < - 88 in Vizier 15 were matched to objects on the frames in good weather conditions recorded in the first quarter of 2009 May 17.…”

“…With the first yearʼs data, Zou et al (2010) investigated the statistics of sky brightness and transparency, and Zhou et al (2010a) published a catalog of about 10,000 stars. Using the i-band data from 2008, Wang et al (2011, 2013 reported observations of 222 variable stars, about four times the number of variables known from previous surveys of this region. In 2012 January, CSTAR was replaced by the first of three second-generation Chinese Antarctic Survey Telescopes (AST3; Yuan et al 2010) at Kunlun Station, Dome A.…”

“…The photometric precision for bright stars reached the few mmag range (Wang et al 2011(Wang et al , 2013 Høg et al 2000), has a proper motion of −21.64 ± 0.84 mas yr − in R.A., 14.22 ± 0.82 mas yr − in decl. and a parallax of 2.12 ± 0.91 mas (van Leeuwen 2007).…”