Photometry of Variable Stars from Dome A, Antarctica: Results from the 2010 Observing Season

TL;DR

This study reports on a two-year photometric survey of 20,000 stars at Dome A, Antarctica, identifying 188 variable stars and demonstrating the site's excellent observing conditions with minimal cloud extinction.

Contribution

First extensive high-cadence photometry from Dome A, discovering new variable stars and providing detailed site statistics for Antarctic astronomy.

Findings

188 variable stars identified, including 67 new discoveries.

Cloud extinction at Dome A is less than 0.1 mag during 45% of dark time.

Site conditions are highly favorable for astronomical observations.

Abstract

We present results from a season of observations with the Chinese Small Telescope ARray (CSTAR), obtained over 183 days of the 2010 Antarctic winter. We carried out high-cadence time-series aperture photometry of 20,000 stars with i<15.3 mag located in a 23 square-degree region centered on the south celestial pole. We identified 188 variable stars, including 67 new objects relative to our 2008 observations, thanks to broader synoptic coverage, a deeper magnitude limit and a larger field of view. We used the photometric data set to derive site statistics from Dome A. Based on two years of observations, we find that extinction due to clouds at this site is less than 0.1 and 0.4 mag during 45% and 75% of the dark time, respectively.