Discovery of a warm, dusty giant planet around HIP65426
Creators: name: Chauvin, G.
name: Desidera, S.
name: Lagrange, A. -M.
name: Vigan, A.
name: Gratton, R.
name: Langlois, M.
name: Bonnefoy, M.
name: Beuzit, J. -L.
name: Feldt, M.
name: Mouillet, D.
name: Meyer, M.
name: Cheetham, A.
name: Biller, B.
name: Boccaletti, A.
name: D'Orazi, V.
name: Galicher, R.
name: Hagelberg, J.
name: Maire, A. -L.
name: Mesa, D.
name: Olofsson, J.
name: Samland, M.
name: Schmidt, T. O. B.
name: Sissa, E.
name: Bonavita, M.
name: Charnay, B.
name: Cudel, M.
name: Daemgen, S.
name: Delorme, P.
name: Janin-Potiron, P.
name: Janson, M.
name: Keppler, M.
name: Coroller, H. Le
name: Ligi, R.
name: Marleau, G. D.
name: Messina, S.
name: Molliere, P.
name: Mordasini, C.
name: Muller, A.
name: Peretti, S.
name: Perrot, C.
name: Rodet, L.
name: Rouan, D.
name: Zurlo, A.
name: Dominik, C.
name: Henning, T.
name: Menard, F.
name: Schmid, H. -M.
name: Turatto, M.
name: Udry, S.
name: Vakili, F.
name: Abe, L.
name: Antichi, J.
name: Baruffolo, A.
name: Baudoz, P.
name: Baudrand, J.
name: Blanchard, P.
name: Bazzon, A.
name: Buey, T.
name: Carbillet, M.
name: Carle, M.
name: Charton, J.
name: Cascone, E.
name: Claudi, R.
name: Costille, A.
name: Deboulbe, A.
name: De Caprio, V.
name: Dohlen, K.
name: Fantinel, D.
name: Feautrier, P.
name: Fusco, T.
name: Gigan, P.
name: Giro, E.
name: Gisler, D.
name: Gluck, L.
name: Hubin, N.
name: Hugot, E.
name: Jaquet, M.
name: Kasper, M.
name: Madec, F.
name: Magnard, Y.
name: Martinez, P.
name: Maurel, D.
name: Mignant, D. Le
name: Moller-Nilsson, O.
name: Llored, M.
name: Moulin, T.
name: Origné, A.
name: Pavlov, A.
name: Perret, D.
name: Petit, C.
name: Pragt, J.
name: Puget, P.
name: Rabou, P.
name: Ramos, J.
name: Rigal, R.
name: Rochat, S.
name: Roelfsema, R.
name: Rousset, G.
name: Roux, A.
name: Salasnich, B.
name: Sauvage, J. -F.
name: Sevin, A.
name: Soenke, C.
name: Stadler, E.
name: Suarez, M.
name: Weber, L.
name: Wildi, F.
name: Antoniucci, S.
name: Augereau, J. -C.
name: Baudino, J. -L.
name: Brandner, W.
name: Engler, N.
name: Girard, J.
name: Gry, C.
name: Kral, Q.
name: Kopytova, T.
name: Lagadec, E.
name: Milli, J.
name: Moutou, C.
name: Schlieder, J.
name: Szulágyi, J.
name: Thalmann, C.
name: Wahhaj, Z.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The SHINE program is a large high-contrast near-infrared survey of 600 young, nearby stars. It is aimed at searching for and characterizing new planetary systems using VLT/SPHERE's unprecedented high-contrast and high-angular resolution imaging capabilities. It also intends at placing statistical constraints on the occurrence and orbital properties of the giant planet population at large orbits as a function of the stellar host mass and age to test planet formation theories. We use the IRDIS dual-band imager and the IFS integral field spectrograph of SPHERE to acquire high-constrast coronagraphic differential near-infrared images and spectra of the young A2 star HIP65426. It is a member of the ~17 Myr old Lower Centaurus-Crux association. At a separation of 830 mas (92 au projected) from the star, we detect a faint red companion. Multi-epoch observations confirm that it shares common proper motion with HIP65426. Spectro-photometric measurements extracted with IFS and IRDIS between 0.95 and 2.2um indicate a warm, dusty atmosphere characteristic of young low surface-gravity L5-L7 dwarfs. Hot-start evolutionary models predict a luminosity consistent with a 6-12 MJup, Teff=1300-1600 K and R=1.5 RJup giant planet. Finally, the comparison with Exo-REM and PHOENIX BT-Settl synthetic atmosphere models gives consistent effective temperatures but with slightly higher surface gravity solutions of log(g)=4.0-5.0 with smaller radii (1.0-1.3 RJup). Given its physical and spectral properties, HIP65426b occupies a rather unique placement in terms of age, mass and spectral-type among the currently known imaged planets. It represents a particularly interesting case to study the presence of clouds as a function of particle size, composition, and location in the atmosphere, to search for signatures of non-equilibrium chemistry, and finally to test the theory of planet formation and evolution.
description: 10 pages, 8 figures, 4 tables, accepted for publication in A&amp;A, file updated