ASTEP South: An Antarctic Search for Transiting Planets around the celestial South pole

TL;DR

ASTEP South is a pioneering Antarctic project using a specialized telescope to assess site quality for exoplanet transit searches, demonstrating promising photometric precision and potential for discovering transiting giant planets.

Contribution

First Antarctic telescope setup designed for exoplanet transit detection, showing stable observations and high photometric precision from Dome C.

Findings

Achieved millimagnitude photometric precision for stars brighter than magnitude 12

Detected sufficient stars in the field for potential transiting planet searches

Confirmed the stability and suitability of Dome C for photometric exoplanet surveys

Abstract

ASTEP South is the first phase of the ASTEP project that aims to determine the quality of Dome C as a site for future photometric searches for transiting exoplanets and discover extrasolar planets from the Concordia base in Antarctica. ASTEP South consists of a front-illuminated 4k x 4k CCD camera, a 10 cm refractor, and a simple mount in a thermalized enclosure. A double-glass window is used to reduce temperature variations and its accompanying turbulence on the optical path. The telescope is fixed and observes a 4 x 4 square degrees field of view centered on the celestial South pole. With this design, A STEP South is very stable and observes with low and constant airmass, both being important issues for photometric precision. We present the project, we show that enough stars are present in our field of view to allow the detection of one to a few transiting giant planets, and that the photometric precision of the instrument should be a few mmag for stars brighter than magnitude 12 and better than 10 mmag for stars of magnitude 14 or less.