Direct confirmation of the radial-velocity planet $β$ Pic c
Creators: name: Nowak, M.
name: Lacour, S.
name: Lagrange, A. -M.
name: Rubini, P.
name: Wang, J.
name: Stolker, T.
name: Amorim, A.
name: Asensio-Torres, R.
name: Bauböck, M.
name: Benisty, M.
name: Berger, J. P.
name: Beust, H.
name: Blunt, S.
name: Boccaletti, A.
name: Bonnefoy, M.
name: Bonnet, H.
name: Brandner, W.
name: Cantalloube, F.
name: Charnay, B.
name: Choquet, E.
name: Christiaens, V.
name: Clénet, Y.
name: Foresto, V. Coudé du
name: Cridland, A.
name: de Zeeuw, P. T.
name: Dembet, R.
name: Dexter, J.
name: Drescher, A.
name: Duvert, G.
name: Eckart, A.
name: Eisenhauer, F.
name: Gao, F.
name: Garcia, P.
name: Lopez, R. Garcia
name: Gardner, T.
name: Gendron, E.
name: Genzel, R.
name: Gillessen, S.
name: Girard, J.
name: Haubois, X.
name: Heißel, G.
name: Henning, T.
name: Hinkley, S.
name: Hippler, S.
name: Horrobin, M.
name: Houllé, M.
name: Hubert, Z.
name: Jiménez-Rosales, A.
name: Jocou, L.
name: Kammerer, J.
name: Kervella, P.
name: Keppler, M.
name: Kreidberg, L.
name: Kulikauskas, M.
name: Lapeyrère, V.
name: Bouquin, J. -B. Le
name: Léna, P.
name: Mérand, A.
name: Maire, A. -L.
name: Mollière, P.
name: Monnier, J. D.
name: Mouillet, D.
name: Müller, A.
name: Nasedkin, E.
name: Ott, T.
name: Otten, G.
name: Paumard, T.
name: Paladini, C.
name: Perraut, K.
name: Perrin, G.
name: Pueyo, L.
name: Pfuhl, O.
name: Rameau, J.
name: Rodet, L.
name: Rodríguez-Coira, G.
name: Rousset, G.
name: Scheithauer, S.
name: Shangguan, J.
name: Stadler, J.
name: Straub, O.
name: Straubmeier, C.
name: Sturm, E.
name: Tacconi, L. J.
name: van Dishoeck, E. F.
name: Vigan, A.
name: Vincent, F.
name: von Fellenberg, S. D.
name: Ward-Duong, K.
name: Widmann, F.
name: Wieprecht, E.
name: Wiezorrek, E.
name: Woillez, J.
name: Collaboration, the GRAVITY
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive to planets with a small orbital period, whereas direct detection is more sensitive to planets orbiting at a large distance from their host star. %, and thus on long orbital period. This dichotomy makes it difficult to combine the two techniques on a single target at once. Simultaneous measurements made by direct and indirect techniques offer the possibility of determining the mass and luminosity of planets and a method of testing formation models. Here, we aim to show how long-baseline interferometric observations guided by radial-velocity can be used in such a way. We observed the recently-discovered giant planet $β$ Pictoris c with GRAVITY, mounted on the Very Large Telescope Interferometer (VLTI). This study constitutes the first direct confirmation of a planet discovered through radial velocity. We find that the planet has a temperature of $T = 1250\pm50$\,K and a dynamical mass of $M = 8.2\pm0.8\,M_{\rm Jup}$. At $18.5\pm2.5$\,Myr, this puts $β$ Pic c close to a 'hot start' track, which is usually associated with formation via disk instability. Conversely, the planet orbits at a distance of 2.7\,au, which is too close for disk instability to occur. The low apparent magnitude ($M_{\rm K} = 14.3 \pm 0.1$) favours a core accretion scenario. We suggest that this apparent contradiction is a sign of hot core accretion, for example, due to the mass of the planetary core or the existence of a high-temperature accretion shock during formation.
description: 10 pages