Stellar Variability and Flare Rates from Dome A, Antarctica using 2009 and 2010 CSTAR Observations

• Main Authors: Oelkers, Ryan J., Macri, Lucas M., Wang, Lifan, Ashley, Michael C. B., Cui, Xiangqun, Feng, Long-Long, Gong, Xuefei, Lawrence, Jon S., Qiang, Liu, Luong-Van, Daniel, Pennypacker, Carl R., Yuan, Xiangyan, York, Donald G., Zhou, Xu, Zhu, Zhenxi
• Format: Text
• Language: unknown
• Published: arXiv 2016
• Subjects: Solar and Stellar Astrophysics astro-ph.SR; FOS Physical sciences; Antarctic; The Antarctic; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.48550/arxiv.1603.09699; https://arxiv.org/abs/1603.09699

The Chinese Small Telescope ARray (CSTAR) carried out high-cadence time-series observations of 20.1 square degrees centered on the South Celestial Pole during the 2008, 2009 & 2010 winter seasons from Dome A in Antarctica. The nearly-continuous 6 months of dark conditions during each observing season allowed for >10^6 images to be collected through gri and clear filters, resulting in the detection of >10^4 sources over the course of 3 years of operation. The nearly space-like conditions in the Antarctic plateau are an ideal testbed for the suitability of very small-aperture (<20 cm) telescopes to detect transient events, variable stars and stellar flares. We present the results of a robust search for such objects using difference image analysis of the data obtained during the 2009 & 2010 winter seasons. While no transients were found, we detected 29 flaring events and find a normalized flaring rate of 5+\-4x10^-7 flare/hour for late-K dwarfs, 1+\-1x10^-6 flare/hour for M dwarfs and 7+\-1x10^-7 flare/hour for all other stars in our sample. We suggest future small-aperture telescopes planned for deployment at Dome A would benefit from a tracking mechanism, to help alleviate effects from ghosting, and a finer pixel scale, to increase the telescope's sensitivity to faint objects. We find that the light curves of non-transient sources have excellent photometric qualities once corrected for systematics, and are limited only by photon noise and atmospheric scintillation. : Accepted for Publication in the Astronomical Journal, 14 pages, 12 figures and 2 tables