J/AJ/142/155 Variable stars photometry from Dome A (Wang+, 2011) ================================================================================ Photometry of variable stars from Dome A, Antarctica. Wang L., Macri L.M., Krisciunas K., Wang L., Ashley M.C.B., Cui X., Feng L.-L., Gong X., Lawrence J.S., Liu Q., Luong-Van D., Pennypacker C.R., Shang Z., Storey J.W.V., Yang H., Yang J., Yuan X., York D.G., Zhou X., Zhu Z., Zhu Z. =2011AJ....142..155W ================================================================================ ADC_Keywords: Stars, variable ; Photometry, SDSS Keywords: site testing - stars: variables: general 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 10000 stars with i<14.5mag located in a 23deg^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 {delta} Scuti, {gamma} Doradus, and RR Lyrae variables. One variable may be a transiting exoplanet. Description: An observatory that can operate year round without interruptions is required to best capitalize upon the advantages provided by the Antarctic plateau. We have built such an observatory at Dome A, called PLATO (PLATeau Observatory), and a quad-telescope called CSTAR (the Chinese Small Telescope ARray). Observations were conducted from 2008 March 20 through 2008 July 27; during this interval, more than 287800 frames were acquired with a total integration time of 1615hr. The total amount of raw data collected during the observing season was about 350GB. Two groups have carried out independent analyses of the data; one at the National Astronomical Observatories of the Chinese Academy of Sciences (Zhou et al. 2010PASP..122..347Z) and another at Texas A&M University and Beijing Normal University (present work). File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table3.dat 83 157 Variable stars observed table6.dat 36 639 Fourier analysis of variable star candidates -------------------------------------------------------------------------------- See also: B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2012) I/305 : The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006) J/ApJS/188/473 : Chandra variable guide star catalog (Nichols+, 2010) J/A+A/499/967 : Long-term monitoring of {gamma} Dor stars (Cuypers+, 2009) J/ApJ/598/597 : Frequency analysis of RR Lyrae (Alcock+, 2003) J/AJ/115/1016 : M31B eclipsing binaries and Cepheids (Kaluzny+ 1998) Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 6 I6 --- ID [572/136863] CSTAR identification 8- 17 A10 --- GSC2.3 Identification from Guide Star Catalog (1) 19- 20 I2 h RAh Hour of Right Ascension from GSC2.3 (J2000) (2) 22- 23 I2 min RAm Minute of Right Ascension from GSC2.3 (J2000) 25- 29 F5.2 s RAs Second of Right Ascension from GSC2.3 (J2000) 31 A1 --- DE- [-] Declination sign from GSC2.3 (J2000) (2) 32- 33 I2 deg DEd Degree of Declination from GSC2.3 (J2000) 35- 36 I2 arcmin DEm Arcminute of Declination from GSC2.3 (J2000) 38- 41 F4.1 arcsec DEs Arcsecond of Declination from GSC2.3 (J2000) 43- 47 F5.2 mag imag CSTAR mean i band magnitude 49- 57 F9.6 d Per ? Main period 59- 61 A3 --- n_Per Source of period determination (3) 63- 69 F7.4 d T0 ? Epoch of minimum light (JD-2454500) (4) 71- 83 A13 --- Type Tentative classification of variable type (5) -------------------------------------------------------------------------------- Note (1): The Guide Star Catalog, version 2.3.2 (GSC2.3, Cat. I/305). The GSC2.3 identification differs from GSC2.2 preliminary version: 10 characters, the first four representing the level-6 HTM (Hierarchical Triangular Mesh) coded in base 36 (0..9 and A..Z), and the last 6 represent a zero-filled sequence number assigned to each source upon initial detection. Note (2): If the star is not in GSC2.3, the position is based on the CSTAR master image. Note (3): Code as follows: LS = Lomb-Scargle method (Lomb 1976Ap&SS..39..447L; Scargle 1982ApJ...263..835S); BLS = box fitting algorithm (Kovacs et al. 2002A&A...391..369K); P04 = Fourier decomposition with Period04 program (Lenz & Breger 2005CoAst.146...53L). See section 5.1 for further explanations. Note (4): Of primary eclipse or minimum light (JD-2454500), when applicable. Note (5): Code as follows: [A] = variable from All Sky Automated Survey; [G] = variable from the General Catalog of Variable Stars (Cat. B/gcvs); CW-FO = W Virginis variable, first-overtone pulsator; DCEP-FU = Delta Cephei variable,fundamental-mode pulsator; DSCT = Delta Scuti variable; EC = contact binary; ESD = semi-detached binary; ED = detached binary; GDOR = Gamma Doradus variable; LT = long-term trend; MISC/SR = Miscellaneous/semi-regular variable; RRL = RR Lyrae variable. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table6.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 6 I6 --- ID [572/133742] CSTAR identification 8- 17 F10.6 d-1 Freq Frequency; in units of cycle/day 19- 24 F6.2 mmag Amp [0.23/281.91] amplitude of the peak 26- 30 F5.2 --- S/N Signal-to-noise ratio of each peak 32- 36 A5 --- Notes Relations between primary and other frequencies (1) -------------------------------------------------------------------------------- Note (1): We searched for multiple periods in the time-series photometry of the variables using the Period04 program (Lenz & Breger, 2005CoAst.146...53L). We started by identifying the frequency (f1) that displayed the highest S/N peak in the periodogram. Next we prewhitened the time series (i.e., subtracted off the most significant frequency) and searched for the next highest peak in the frequency spectrum. We repeated the process until all peaks with S/N>4 were identified. For example, consider the variable CSTAR#061353, shown in Figure 17. There are three significant peaks in the periodogram, with f_i_=44.2879, 44.1690, and 42.1209 cycles/day) and S/Ns of 15.8, 15.7, and 15.0, respectively. See section 5.2. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 11-Mar-2013