The origin of R CrA variability: A complex triple system hosting a disk

Abstract

R~CrA is the brightest member of the Coronet star forming region and it is the closest Herbig AeBe star with a spectrum dominated by emission lines. Its luminosity has been monitored since the end of the 19th century, but the origin of its variability, which shows a stable period of $65.767\pm 0.007$~days, is still unknown. We studied photometric and spectroscopic data for this star to investigate the nature of the variability of R~CrA. We exploited the fact that near infrared luminosity of the Herbig AeBe stars is roughly proportional to the total luminosity of the stars to derive the absorption, and then mass and age of R~CrA. In addition, we model the periodic modulation of the light curve as due to partial attenuation of a central binary by a circumbinary disk. This model reproduces very well the observations. We found that the central object in R~CrA is a very young ($1.5\pm 1.5$~Myr), highly absorbed ($A_V=5.47\pm 0.4$~mag) binary; we obtain masses of $M_A=3.02\pm 0.43$~M${}_{\odot }$ and $M_B=2.32\pm 0.35$~M${}_{\odot }$ for the two components. We propose that the secular decrease of the R~CrA apparent luminosity is due to a progressive increase of the disk absorption. This might be related to precession of a slightly inclined disk caused by the recently discovered M-dwarf companion. Thus, R~CrA may be a triple system hosting a disk.

arXiv commentAccepted for publication in A&A. 14 pages, 11 figures

References in corpus (34)

• Gaia Data Release 2. Summary of the contents and survey properties
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Giant Planet Occurrence in the Stellar Mass-Metallicity Plane
• SPHERE: the exoplanet imager for the Very Large Telescope
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Southern Sample
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
• The first WASP public data release
• Pulkovo Compilation of Radial Velocities for 35495 Hipparcos Stars in a Common System
• The Pisa pre-main sequence tracks and isochrones. A database covering a wide range of Z, Y, mass, and age values
• A spectroscopic survey of Herbig Ae/Be stars with X-Shooter I: Stellar parameters and accretion rates
• Gaia DR2 study of Herbig Ae/Be stars
• X-shooter spectroscopy of young stellar objects: I - Mass accretion rates of low-mass T Tauri stars in σOrionis
• Structure of Herbig AeBe disks at the milliarcsecond scale A statistical survey in the H band using PIONIER-VLTI
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. XI. Lupus Observed With IRAC and MIPS
• Parameters of Herbig Ae/Be and Vega-type stars
• A spectro-astrometric study of southern pre-main sequence stars - binaries, outflows, and disc structure down to AU scales
• EXPORT: optical photometry and polarimetry of Vega-type and pre-main sequence stars
• Study of the properties and spectral energy distributions of the Herbig AeBe stars HD 34282 and HD 141569
• Inclined Massive Planets in a Protoplanetary Disc: Gap Opening, Disc Breaking, and Observational Signatures
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds.X. The Chamaeleon II Pre-Main Sequence Population as Observed With IRAC and MIPS
• A Spitzer MIPS Study of 2.5-2.0 M\odot Stars in Scorpius-Centaurus
• Correlations between the stellar, planetary and debris components of exoplanet systems observed by $\text{Herschel}$
• The structure of disks around Herbig Ae/Be stars as traced by CO ro-vibrational emission
• Radio and X-ray variability of Young Stellar Objects in the Coronet Cluster
• Revealing the sub-AU asymmetries of the inner dust rim in the disk around the Herbig Ae star R CrA
• The SPHERE view of the jet and the envelope of RY Tau
• Exploring the RCrA environment with SPHERE: Discovery of a new stellar companion
• A parameter study of self-consistent disk models around Herbig AeBe stars
• Optical and Radio Observations of the T Tauri Binary KH 15D (V582 Mon): Stellar Properties, Disk Mass Limit and Discovery of a CO Outflow
• Kinematics of Vega-like stars: lifetimes and temporal evolution of circumstellar dust disks

Cited by in corpus (9)

• A family portrait of disk inner rims around Herbig Ae/Be stars: Hunting for warps, rings, self shadowing, and misalignments in the inner astronomical units
• Interferometric study on the temporal variability of the brightness distributions of protoplanetary disks
• Investigating the nature of the extended structure around the Herbig star RCrA using integral field and high-resolution spectroscopy
• ISPY -- NaCo Imaging Survey for Planets around Young stars. CenteR: the impact of centering and frame selection
• Polarimetric differential imaging with VLT/NACO. A comprehensive PDI pipeline for NACO data (PIPPIN)
• The Corona-Australis star-forming region: New insights on its formation history from detailed stellar and disk analysis
• The SPHERE view of multiple star formation
• Feasibility of interferometric observations and characterization of planet-induced structures at sub au to au scales in protoplanetary disks
• FORCAST imaging of two small nearby Clusters: The Coronet and B59