Exoplanets in the Antarctic Sky. II. 116 Transiting Exoplanet Candidates Found by AST3-II (CHESPA) within the Southern CVZ of TESS

Abstract

We report first results from the CHinese Exoplanet Searching Program from Antarctica (CHESPA)a wide-field high-resolution photometric survey for transiting exoplanets carried out using telescopes of the AST3 (Antarctic Survey Telescopes times 3) project. There are now three telescopes (AST3-I, AST3-II, and CSTAR-II) operating at Dome A-the highest point on the Antarctic Plateau-in a fully automatic and remote mode to exploit the superb observing conditions of the site, and its long and uninterrupted polar nights. The search for transiting exoplanets is one of the key projects for AST3. During the austral winters of 2016 and 2017 we used the AST3-II telescope to survey a set of target multiple innovations in the telescope's snow-proofing and defrosting systems. As a result, AST3-II worked well during the extremely cold austral winters of 2016 and 2017, and acquired over 30 TB of high-quality images. During the observational seasons in austral winter, AST3-II is operated remotely and the scheduled observations are executed in a fully-automatic mode. The hardware and software for the facility-including the hardware operation monitor, telescope control computer, and data storage array-were developed by the National Astronomical Observatories, Chinese Academy of Sciences (NAOC) (Shang et al. 2012;Hu et al. 2016). The electrical power supply and internet communication were provided by a similarly reliable on-site observatory platform, PLATO-A, which is an improved version of the PLATO system developed by UNSW Sydney as an automated observatory platform for CSTAR and other earlier instruments. PLATO-A was designed to provide a continuous 1 kW power source, a warm environment for equipment, and internet communications to the AST3 telescopes for a year without servicing Ashley et al. 2010). OBSERVATIONSThe scientific background and observational strategy of CHESPA are described in Zhang et al. (2018). We summarize the key points here. The CHESPA program is dedicated to searching for transiting exoplanets in the southern polar sky at highly negative declinations. It has been running since 2012 using the CSTAR and AST3 telescopes, with a first batch of six exoplanet candidates published by Wang et al. (2014). To maximize collaboration with TESS and enhance the scientific importance of our searching program, we selected 48 target fields close to the South Ecliptic Pole (RA = 06 h 00 m 00 s , Dec = −66 • 33 00 ) and within the TESS ' Southern CVZ (Continuous Viewing Zone) (see Figure 1 and Table 1 for details). All target fields are and are suitable for low-airmass observation from Antarctica. Target stars located in these fields will also be monitored by TESS for continuous 12 month period. Thus, any candidate of interest found within these fields may be followed up and studied thoroughly in the future.These chosen fields are divided into three groups, each of which was originally scheduled for observation over an austral winter in we observed the first group consisting of 10 fields (AST3II004-AST3II013). The second group c...

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