Volume 629, September 2019
|Number of page(s)||18|
|Section||Interstellar and circumstellar matter|
|Published online||27 August 2019|
HR 10: a main-sequence binary with circumstellar envelopes around both components
Discovery and analysis★
Departmento de Astrofísica, Centro de Astrobiología (CAB, CSIC-INTA), ESAC Campus,
Camino Bajo del Castillo s/n,
Villanueva de la Cañada, Madrid,
2 Departamento Física Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
3 Observatorio Astrónomico de Calar Alto, CAHA, 04550 Gérgal, Almería, Spain
4 European Southern Observatory (ESO), Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile
5 Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Santa Cruz de Tenerife, Spain
6 Space sciences, Technologies, and Astrophysics Research (STAR) Institute, University of Liège, Belgium
7 Large Binocular Telescope Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA
8 Steward Observatory, Department of Astronomy, University of Arizona, 993 N. Cherry Avenue, Tucson, AZ 85721, USA
9 Finnish Centre for Astronomy with ESO (FINCA), University of Turku, 20014 Finland
10 Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT 06459, USA
11 Department of Astronomy, University of California, Berkeley, CA, USA
12 ESA–ESAC, Operations Department, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
13 Aurora Technology B.V. for ESA, ESA–ESAC, Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
14 Observatorio Astronómico Nacional (OAN-IGN) – Observatorio de Madrid, Alfonso XII, 3, 28014 Madrid, Spain
15 INAF – Osservatorio Astronomico di Palermo Piazza del Parlamento 1, 90134 Palermo, Italy
16 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
Accepted: 13 July 2019
Context. This paper is framed within a large project devoted to studying the presence of circumstellar material around main sequence stars, and looking for exocometary events. The work concentrates on HR 10 (A2 IV/V), known for its conspicuous variability in the circumstellar narrow absorption features of Ca II K and other lines, so far interpreted as β Pic-like phenomena, within the falling evaporating body scenario.
Aims. The main goal of this paper is to carry out a thorough study of HR 10 to find the origin of the observed variability, determine the nature of the star, its absolute parameters, and evolutionary status.
Methods. Interferometric near-infrared (NIR) observations, multi-epoch high-resolution optical spectra spanning a time baseline of more than 32 yr, and optical and NIR photometry, together with theoretical modelling, were used to tackle the above objectives.
Results. Our results reveal that HR 10 is a binary. The narrow circumstellar absorption features superimposed on the photospheric Ca II K lines – and lines of other species – can be decomposed into two or more components, the two deep ones tracing the radial velocity of the individual stars, which implies that their origin cannot be ascribed to transient exocometary events, their variability being fully explained by the binarity of the object. There does not appear to be transient events associated with potential exocomets. Each individual star holds its own circumstellar shell and there are no traces of a circumbinary envelope. Finally, the combined use of the interferometric and radial velocity data leads to a complete spectrometric and orbital solution for the binary, the main parameters being: an orbital period of 747.6 days, eccentricities of the orbits around the centre of mass 0.25 (HR 10-A), 0.21 (HR 10-B) and a mass ratio of q = MB∕MA = 0.72–0.84. The stars are slightly off the main sequence, the binary being ~530 Myr old.
Key words: binaries: general / circumstellar matter / stars: fundamental parameters / techniques: interferometric / techniques: spectroscopic
Partially based on observations obtained with PIONIER/VLT (ESO, Paranal, Chile), FIES/NOT, HERMES/Mercator, HARPS-N/TNG and UES/WHT (La Palma, Spain), FEROS/2.2-m ESO-MPIA (La Silla, Chile), CS21/Harlan J. Smith Telescope (McDonald Observatory, US) and UHRF/3.6-m AAT (Anglo Australian Observatory), and archival data from HARPS/3.6-m ESO and UVES/VLT (ESO archive), and HIRES/Keck 1 (Keck archive).
© ESO 2019
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.