Discovery of a warm, dusty giant planet around HIP65426
Abstract
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.
Keywords
Cite
@article{arxiv.1707.01413,
title = {Discovery of a warm, dusty giant planet around HIP65426},
author = {G. Chauvin and S. Desidera and A. -M. Lagrange and A. Vigan and R. Gratton and M. Langlois and M. Bonnefoy and J. -L. Beuzit and M. Feldt and D. Mouillet and M. Meyer and A. Cheetham and B. Biller and A. Boccaletti and V. D'Orazi and R. Galicher and J. Hagelberg and A. -L. Maire and D. Mesa and J. Olofsson and M. Samland and T. O. B. Schmidt and E. Sissa and M. Bonavita and B. Charnay and M. Cudel and S. Daemgen and P. Delorme and P. Janin-Potiron and M. Janson and M. Keppler and H. Le Coroller and R. Ligi and G. D. Marleau and S. Messina and P. Molliere and C. Mordasini and A. Muller and S. Peretti and C. Perrot and L. Rodet and D. Rouan and A. Zurlo and C. Dominik and T. Henning and F. Menard and H. -M. Schmid and M. Turatto and S. Udry and F. Vakili and L. Abe and J. Antichi and A. Baruffolo and P. Baudoz and J. Baudrand and P. Blanchard and A. Bazzon and T. Buey and M. Carbillet and M. Carle and J. Charton and E. Cascone and R. Claudi and A. Costille and A. Deboulbe and V. De Caprio and K. Dohlen and D. Fantinel and P. Feautrier and T. Fusco and P. Gigan and E. Giro and D. Gisler and L. Gluck and N. Hubin and E. Hugot and M. Jaquet and M. Kasper and F. Madec and Y. Magnard and P. Martinez and D. Maurel and D. Le Mignant and O. Moller-Nilsson and M. Llored and T. Moulin and A. Origné and A. Pavlov and D. Perret and C. Petit and J. Pragt and P. Puget and P. Rabou and J. Ramos and R. Rigal and S. Rochat and R. Roelfsema and G. Rousset and A. Roux and B. Salasnich and J. -F. Sauvage and A. Sevin and C. Soenke and E. Stadler and M. Suarez and L. Weber and F. Wildi and S. Antoniucci and J. -C. Augereau and J. -L. Baudino and W. Brandner and N. Engler and J. Girard and C. Gry and Q. Kral and T. Kopytova and E. Lagadec and J. Milli and C. Moutou and J. Schlieder and J. Szulágyi and C. Thalmann and Z. Wahhaj},
journal= {arXiv preprint arXiv:1707.01413},
year = {2017}
}
Comments
10 pages, 8 figures, 4 tables, accepted for publication in A&A, file updated