Transiting planet candidates with ASTEP 400 at Dome C, Antarctica

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Mekarnia, D., Guillot, T., Rivet, J. -P., Schmider, F. -X., Abe, L., Goncalves, I., Agabi, A., Crouzet, N., Fruth, T., Barbieri, M., Bayliss, D. D. R., Zhou, G., Aristidi, E., Szulagyi, J., Daban, J. -B., Fanteï-Caujolle, Y., Gouvret, C., Erikson, A., Rauer, H., Bouchy, F., Gerakis, J., Bouchez, G.
• Other Authors: Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Universidad de Atacama, Laboratoire Hippolyte Fizeau (FIZEAU), DLR Institute of Planetary Research, German Aerospace Center (DLR), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt Berlin (DLR), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; Concordia Station; Antarc*; Antarctica
• Online Access: https://hal.science/hal-01440131; https://hal.science/hal-01440131/document; https://hal.science/hal-01440131/file/stw1934.pdf; https://doi.org/10.1093/mnras/stw1934

International audience ASTEP 400, the main instrument of the ASTEP (Antarctica Search for Transiting ExoPlanets) programme, is a 40 cm telescope, designed to withstand the harsh conditions in Antarctica, achieving a photometric accuracy of a fraction of millimagnitude on hourly time-scales for planet-hosting southern bright (R = 12 mag) stars. We review the performances of this instrument, describe its operating conditions, and present results from the analysis of observations obtained during its first three years (2010-2012) of operation, before its repatriation in 2014. During this time, we observed a total of 22 stellar fields (1A degrees x 1A degrees field of view). Each field, in which we measured stars up to magnitude R = 18 mag, was observed continuously during =7 to =30 d. More than 200 000 frames were recorded and 310 000 stars processed, using an implementation of the optimal image subtraction photometry algorithm. We found 43 planetary transit candidates. 20 of these candidates were observed using spectroscopic follow-ups including four targets classified as good planet candidates. Our results demonstrate that accurate near-continuous photometric observations are achievable from the Concordia station at Dome C in Antarctica, even if we were not able to reach the nominal photometric precision of the instrument. We conducted a correlation analysis between the rms noise and a large number of external parameters and found that source of the =1 mmag correlated noise is not obvious and does not depend on a single parameter. However, our analysis provided some hints and guidance to increase the photometric accuracy of the instrument. These improvements should equip any future telescope operating in Antarctica.