Volume 617, September 2018
|Number of page(s)||21|
|Section||Stellar structure and evolution|
|Published online||18 September 2018|
Characterization of low-mass companion HD 142527 B⋆
Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
2 Space sciences, Technologies & Astrophysics Research (STAR) Institute, Université de Liège, Allée du Six Août 19c, 4000 Sart Tilman, Belgium
3 Millenium Nucleus “Protoplanetary Disks”, Chile
4 Instituto de Astronomía, Universidad Católica del Norte, Avenida Angamos 0610 Antofagasta, Chile
5 Institut für Astro– und Teilchenpysik, Leopold–Franzens Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria
6 Space Telescope Science Institute, 3700 San Martin Dr. Baltimore, MD 21218, USA
7 Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
8 Núcleo de Astronomía, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
9 Escuela de Ingeniería Industrial, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile
10 European Southern Observatory, Alonso de Córdova, 3107 Vitacura, Santiago, Chile
11 Institute for Astronomy, University of Hawaii, 640 N. Aohoku Place, Hilo, HI, 96720 USA
12 Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima, 890-0065 Japan
13 Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, 7820436 Macul, Santiago, Chile
14 Department of Astronomy, California Institute of Technology, 1200 E. California Blvd, Pasadena, 91125 USA
15 Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, CA, 91109 USA
Accepted: 12 June 2018
Context. The circumstellar disk of the Herbig Fe star HD 142527 is host to several remarkable features including a warped inner disk, a 120 au-wide annular gap, a prominent dust trap and several spiral arms. A low-mass companion, HD 142527 B, was also found orbiting the primary star at ~14 au.
Aims. This study aims to better characterize this companion, which could help explain its impact on the peculiar geometry of the disk.
Method. We observed the source with VLT/SINFONI in H + K band in pupil-tracking mode. Data were post-processed with several algorithms based on angular differential imaging (ADI).
Results. HD 142527 B is conspicuously re-detected in most spectral channels, which enables us to extract the first medium-resolution spectrum of a low-mass companion within 0.″1 from its central star. Fitting our spectrum with both template and synthetic spectra suggests that the companion is a young M2.5 ± 1.0 star with an effective temperature of 3500 ± 100 K, possibly surrounded with a hot (1700 K) circum-secondary environment. Pre-main sequence evolutionary tracks provide a mass estimate of 0.34 ± 0.06 M⊙, independent of the presence of a hot environment. However, the estimated stellar radius and age do depend on that assumption; we find a radius of 1.37 ± 0.05 R⊙ (resp. 1.96 ± 0.10 R⊙) and an age of 1.8-0.5+1.2 Myr (resp. 0.75 ± 0.25 Myr) in the case of the presence (resp. absence) of a hot environment contributing in H + K. Our new values for the mass and radius of the companion yield a mass accretion rate of 4.1–5.8 × 10−9 M⊙ yr−1 (2–3% that of the primary).
Conclusions. We have constrained the physical properties of HD 142527 B, thereby illustrating the potential for SINFONI+ADI to characterize faint close-in companions. The new spectral type makes HD 142527 B a twin of the well-known TW Hya T Tauri star, and the revision of its mass to higher values further supports its role in shaping the disk.
Key words: protoplanetary disks / stars: individual: HD 142527 / stars: low-mass / binaries: close / stars: pre-main sequence
© ESO 2018
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