Post-conjunction detection of β Pictoris b with VLT/SPHERE

Anne-Marie Lagrange (1) , Anthony Boccaletti (2) , Maud Langlois (3, 4) , Gael Chauvin (1, 5) , Raffaele Gratton (6) , Hervé Beust (1) , Silvano Desidera (6) , Julien Milli (7) , Mickael Bonnefoy (1) , Anthony Cheetham (8) , Markus Feldt (9) , Matthias Meyer (10, 11) , Arthur Vigan (3) , Beth Biller (9, 12) , Mariangela Bonavita (6, 12) , Jean-Loup Baudino (6, 13) , Faustine Cantalloube (9) , Maxime Cudel (1) , Sebastian Daemgen (10) , Philippe Delorme (1) , Valentina d'Orazi (6) , Julien Girard (1) , Clemence Fontanive (6, 12) , Janis Hagelberg (1) , Martin Janson (9, 14) , Miriam Keppler (9) , T. Koypitova (9) , Raphaël Galicher (2) , Justine Lannier (1) , Hervé Le Coroller (3) , Roxanne Ligi (3, 15) , Anne-Lise Maire (9) , Dino Mesa (6) , Sergio Messina (16) , André Mueller (9) , Sébastien Peretti (8) , Clément Perrot (2) , Daniel Rouan (2) , Graeme Salter (3) , Matthias Samland (9) , Tobias Schmidt (2) , Emanuele Sissa (6) , Alice Zurlo (3, 17) , Jean-Luc Beuzit (1) , David Mouillet (1) , Carsten Dominik (18) , Thomas Henning (9) , Eric Lagadec (19) , François Menard (1) , Hans Martin Schmid (10) , Massimo Turatto (6) , Stéphane Udry (8) , Alexander Julian Bohn (20) , Benjamin Charnay (2) , Carlos. A. Gomez Gonzales (1) , Cécile Gry (3) , Matthew Kenworthy (20) , Quentin Kral (2) , Christoph Mordasini (21) , Claire Moutou (3) , Gerrit van Der Plas (20) , Joshua E. Schlieder (8, 22) , Lyu Abe (19) , Jacopo Antichi (23) , Andrea Baruffolo (6) , Pierre Baudoz (2) , Jacques Baudrand (2) , Patrick Blanchard (3) , Andreas Bazzon (10) , Tristan Buey (2) , Marcel Carbillet (19) , Michaël Carle (3) , Julien Charton (1) , Enrico Cascone (24) , Riccardo Claudi (6) , Anne Costille (3) , Alain Deboulbe (1) , Vincenzo de Caprio (24) , Kjetil Dohlen (3) , Daniela Fantinel (6) , Philippe Feautrier (1) , Thierry Fusco (25) , Pierre Gigan (2) , Enrico Giro (6) , Daniel Gisler (10) , Laurence Gluck (1) , Norbert Hubin (26) , Emmanuel Hugot (3) , Marc Jaquet (3) , Markus Kasper (26) , Fabrice Madec (3) , Yves Magnard (1) , Patrice Martinez (19) , Didier Maurel (1) , David Le Mignant (3) , O. Moller-Nilsson (9) , Marc Llored (3) , Thibaut Moulin (1) , Alain Origné (3) , A. Pavlov (9) , Denis Perret (2) , Cyril Petit (25) , Johan Pragt (27) , J. Szulagyi (28) , François Wildi (8)

1 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
2 LESIA (UMR_8109) - Laboratoire d'études spatiales et d'instrumentation en astrophysique
3 LAM - Laboratoire d'Astrophysique de Marseille
4 CRAL - Centre de Recherche Astrophysique de Lyon
5 UCHILE - Universidad de Chile = University of Chile [Santiago]
6 OAPD - INAF - Osservatorio Astronomico di Padova
7 ESO - European Southern Observatory [Santiago]
8 ObsGE - Observatoire Astronomique de l'Université de Genève
9 MPIA - Max-Planck-Institut für Astronomie
10 ETH Zürich - Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich]
11 University of Michigan [Ann Arbor]
12 SUPA School of Physics and Astronomy [Edinburgh]
13 Sub-department of Astrophysics [Oxford]
14 Stockholm University
15 OAB - INAF - Osservatorio Astronomico di Brera
16 OACT - INAF - Osservatorio Astrofisico di Catania
17 UDP - Universidad Diego Portales [Santiago - Chili]
18 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
19 OCA - Observatoire de la Côte d'Azur
20 Leiden Observatory [Leiden]
21 Physikalisches Institut [Bern]
22 GSFC - NASA Goddard Space Flight Center
23 OAA - INAF - Osservatorio Astrofisico di Arcetri
24 OAC - INAF - Osservatorio Astronomico di Capodimonte
25 DOTA, ONERA, Université Paris Saclay (COmUE) [Châtillon]
26 ESO - European Southern Observatory
27 NOVA Optical Infrared Instrumentation Group
28 Institute of Astronomy [ETH Zürich]

Context. With an orbital distance comparable to that of Saturn in the solar system, β Pictoris b is the closest (semi-major axis ≃9 au) exoplanet that has been imaged to orbit a star. Thus it offers unique opportunities for detailed studies of its orbital, physical, and atmospheric properties, and of disk-planet interactions. With the exception of the discovery observations in 2003 with NaCo at the Very Large Telescope (VLT), all following astrometric measurements relative to β Pictoris have been obtained in the southwestern part of the orbit, which severely limits the determination of the planet’s orbital parameters. Aims. We aimed at further constraining β Pictoris b orbital properties using more data, and, in particular, data taken in the northeastern part of the orbit. Methods. We used SPHERE at the VLT to precisely monitor the orbital motion of beta β Pictoris b since first light of the instrument in 2014. Results. We were able to monitor the planet until November 2016, when its angular separation became too small (125 mas, i.e., 1.6 au) and prevented further detection. We redetected β Pictoris b on the northeast side of the disk at a separation of 139 mas and a PA of 30° in September 2018. The planetary orbit is now well constrained. With a semi-major axis (sma) of a = 9.0 ± 0.5 au (1σ), it definitely excludes previously reported possible long orbital periods, and excludes β Pictoris b as the origin of photometric variations that took place in 1981. We also refine the eccentricity and inclination of the planet. From an instrumental point of view, these data demonstrate that it is possible to detect, if they exist, young massive Jupiters that orbit at less than 2 au from a star that is 20 pc away.

Mots clés: planetary systems; stars: individual: HR 2020; instrumentation: high angular resolution; planetary systems

Domaines: Astrophysique galactique [astro-ph.GA]

Anne-Marie Lagrange, Anthony Boccaletti, Maud Langlois, Gael Chauvin, Raffaele Gratton, et al.. Post-conjunction detection of β Pictoris b with VLT/SPHERE. Astronomy and Astrophysics - A&A, 2019, 621, pp.L8. ⟨10.1051/0004-6361/201834302⟩. ⟨hal-02107856⟩