Volume 624, April 2019
|Number of page(s)||11|
|Section||Stellar structure and evolution|
|Published online||29 March 2019|
Exploring the R CrA environment with SPHERE
INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
2 INCT, Universidad De Atacama, Calle Copayapu 485, Copiapó, Atacama, Chile
3 Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
4 Nucleo de Astronomia, Facultad de Ingenieria y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
5 Escuela de Ingenieria Industrial, Facultad de Ingenieria y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
6 Aix Marseille Univ., CNRS, CNES, LAM, Marseille, France
7 Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
8 LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne, Paris Cité, 5 Place Jules Janssen, 92195 Meudon, France
9 Univ. Lyon, Univ. Lyon 1, ENS de Lyon, CNRS, CRAL UMR 5574, 69230 Saint-Genis-Laval, France
10 Dipartimento di Fisica, Universitá Degli Studi di Milano, Via Celoria, 16, 20133 Milano, Italy
11 INAF-Osservatorio Astronomico di Roma, Via di Frascati 33, 00078 Monte Porzio Catone, Italy
12 Unidad Mixta Internacional Franco-Chilena de Astronoma (CNRS, UMI 3386), Departamento de Astronoma, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
13 INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
14 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
15 European Southern Observatory (ESO), Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
16 Department of Astronomy, University of Michigan, 1085 S. University Ave, Ann Arbor, MI 48109-1107, USA
17 Space Sciences, Technologies & Astrophysics Research (STAR) Institute, Université de Liege, Allée du Six Aout 19c, 4000 Sart Tilman, Belgium
18 Geneva Observatory, University of Geneva, Chemin des Maillettes 51, 1290 Versoix, Switzerland
19 AlbaNova University Center, Stockholm University, Stockholm, Sweden
20 INAF-Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23807 Merate, Italy
21 DOTA, ONERA, Université Paris Saclay, 91123 Palaiseau, France
22 Anton Pannekoek Institute for Astronomy, Science Park 904, 1098 XH Amsterdam, The Netherlands
Accepted: 6 February 2019
Aims. R Coronae Australis (R CrA) is the brightest star of the Coronet nebula of the Corona Australis (CrA) star forming region. This star is very red in color, probably due to dust absorption, and is strongly variable. High-contrast instruments allow for an unprecedented direct exploration of the immediate circumstellar environment of this star.
Methods. We observed R CrA with the near-infrared (NIR) channels (IFS and IRDIS) of SPHERE at the Very Large Telescope (VLT). In this paper, we used four different epochs, three of which are from open time observations while one is from SPHERE guaranteed time. The data were reduced using the data reduction and handling pipeline and the SPHERE Data Center. We implemented custom IDL routines on the reduced data with the aim to subtract the speckle halo. We have also obtained pupil-tracking H-band (1.45−1.85 μm) observations with the VLT/SINFONI NIR medium-resolution (R ∼ 3000) spectrograph.
Results. A companion was found at a separation of 0.156″ from the star in the first epoch and increasing to 0.184″ in the final epoch. Furthermore, several extended structures were found around the star, the most noteworthy of which is a very bright jet-like structure northeast from the star. The astrometric measurements of the companion in the four epochs confirm that it is gravitationally bound to the star. The SPHERE photometry and SINFONI spectrum, once corrected for extinction, point toward a spectral type object that is early M with a mass between 0.3 and 0.55 M⊙. The astrometric analyis provides constraints on the orbit paramenters: e ∼ 0.4, semimajor axis at 27–28 au, inclination of ∼70°, and a period larger than 30 yr. We were also able to put constraints of few MJup on the mass of possible other companions down to separations of few tens of au.
Key words: instrumentation: spectrographs / methods: data analysis / techniques: imaging spectroscopy / stars: pre-main sequence / stars: individual: R CrA
Based on observations made with European Southern Observatory (ESO) telescopes at Paranal Observatory in Chile, under programs ID 095.C-0787(A), 097.C-0591(A), 1100.C-0481(H), 0101.C-0350(A) and 2101.C-5048(A).
The SPHERE and SINFONI images are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/624/A4
© ESO 2019
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