Searching for transiting cold Jupiters around bright stars with ASTEP South at Dome C, Antarctica

• Main Authors: Crouzet, N., Mékarnia, D., Guillot, T., Bayliss, D., Deeg, H., Palle, E., Abe, L., Agabi, A., Rivet, J., Murgas, F., Gillon, M., Delrez, L., Jehin, E., Espinoza, N.
• Format: Conference Object
• Language: unknown
• Published: 2019
• Subjects: South Pole; Antarc*; Antarctica; South pole
• Online Access: http://hdl.handle.net/21.11116/0000-0005-D3CB-8

Much of our understanding of gas giant exoplanets come from those transiting in front of bright stars at small orbital separations (P 3 days, a 0.05 au). These hot Jupiters are coupled to their host star: stellar irradiation impacts the chemistry and temperature structure of their atmospheres and tidal interactions affects the orbital dynamics and may even impact the star itself. In contrast, gas giant exoplanets with long orbital periods and large separations (P > 30 days, a > 0.2 au) are much less coupled to their host star and provide ideal benchmarks to study gas giant planets in general. However, only a few transiting "cold Jupiters" orbiting bright stars are known to date. In the past years, we conducted the ASTEP experiment (Antarctica Search for Transiting ExoPlanets) to search and characterize transiting exoplanets from Dome C, Antarctica and to qualify this site for photometry in the visible. One instrument, ASTEP South, is a 10 cm diameter lens equipped with a CCD camera in a thermalised box pointing continuously towards the celestial South pole. We analysed four winters of data collected with this instrument and identified about 30 transit candidates around relatively bright stars (9 < V < 13) with orbital periods up to 80 days. We performed photometric follow-up with the Las Cumbres Observatory (LCO) 0.4m telescopes to investigate these signals. Most of these stars are also observed by TESS and their lightcurves can be extracted from the full frame images. In this poster, we present our set of candidates, the first results of the photometric follow-up, and discuss the use of TESS data to investigate these objects.