HR 10: A main-sequence binary with circumstellar envelopes around both components. Discovery and analysis
arXiv:1907.12441 · doi:10.1051/0004-6361/201936180
Abstract
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 Pic-like phenomena, within the falling evaporating body scenario. 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. Interferometric near-infrared (NIR) observations, multi-epoch high-resolution optical spectra spanning a time baseline of more than 32 years, and optical and NIR photometry, together with theoretical modelling, were used to tackle the above objectives. 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. 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=M/M=0.72-0.84. The stars are slightly off the main sequence, the binary being Myr old.
18 pages, 17 figures
References in corpus (31)
- emcee: The MCMC Hammer
- PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
- The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
- Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
- Spectral Irradiance Calibration in the Infrared. XIV: the Absolute Calibration of 2MASS
- Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
- Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
- The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
- PIONIER: a 4-telescope visitor instrument at VLTI
- An Empirical UBVRIJHK Color-Temperature Calibration for Stars
- The Effect of Stellar Rotation on Colour-Magnitude Diagrams: On the apparent presence of multiple populations in intermediate age stellar clusters
- A Resolved Census of Millimeter Emission from Taurus Multiple Star Systems
- A 40 Myr Old Gaseous Circumstellar Disk at 49 Ceti: Massive CO-Rich Comet Clouds at Young A-Type Stars
- Exocometary gas in the HD 181327 debris ring
- Parameters of Herbig Ae/Be and Vega-type stars
- A near-infrared interferometric survey of debris disc stars. III. First statistics based on 42 stars observed with CHARA/FLUOR
- A near-infrared interferometric survey of debris-disc stars. IV. An unbiased sample of 92 southern stars observed in H-band with VLTI/PIONIER
- Binaries Among Debris Disk Stars
- Transient dust in warm debris disks - Detection of Fe-rich olivine grains
- A near-infrared interferometric survey of debris-disc stars. V. PIONIER search for variability
- The HOSTS survey - Exozodiacal dust measurements for 30 stars
- Searching for faint companions with VLTI/PIONIER. I. Method and first results
- Spitzer Limits On Dust Emission and Optical Gas Absorption Variability Around Nearby Stars with Edge-On Circumstellar Disk Signatures
- Inner mean-motion resonances with eccentric planets: A possible origin for exozodiacal dust clouds
- The co-existence of hot and cold gas in debris discs
- Exocomet signatures around the A-shell star Leo?
- Debris Disks Around Nearby Stars with Circumstellar Gas
- Searching for faint companions with VLTI/PIONIER. II. 92 main sequence stars from the Exozodi survey
- The Exoplanet Simple Orbit Fitting Toolbox (ExoSOFT): An Open-Source Tool for Efficient Fitting of Astrometric and Radial Velocity Data
- Gravity darkening in stars with surface differential rotation
- Herbig AeBe stars: Multiplicity and consequences