Exoplanets in the Antarctic Sky. II. 116 Transiting Exoplanet Candidates Found by AST3-II (CHESPA) within the Southern CVZ of TESS
Résumé
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 fields near the southern ecliptic pole, falling within the continuous
viewing zone of the TESS mission \citep{Ricker10}. The first data release of
the 2016 data, including images, catalogs and lightcurves of 26578 bright stars
($7.5\le i \le15$) was presented in \citet{Zhang18}. The best precision, as
measured by the RMS of the lightcurves at the optimum magnitude of the survey
($i=10$), is around 2\,mmag. We detect 222 objects with plausible transit
signals from these data, 116 of which are plausible transiting exoplanet
candidates according to their stellar properties as given by the TESS Input
Catalog \citep{Stassun17}, Gaia DR2 \citep{Gaia18} and TESS-HERMES spectroscopy
\citep{Sharma18}. With the first data release from TESS expected in late 2018,
this candidate list will be a timely for improving the rejection of potential
false positives.