Fundamental properties and atmospheric structure of the red supergiant VY CMa based on VLTI/AMBER spectro-interferometry

Abstract

We investigate the atmospheric structure and fundamental properties of the red supergiant VY CMa. We obtained near-infrared spectro-interferometric observations of VY CMa with spectral resolutions of 35 and 1500 using the AMBER instrument at the VLTI. The visibility data indicate the presence of molecular layers of water vapor and CO in the extended atmosphere with an asymmetric morphology. The uniform disk diameter in the water band around 2.0 mu is increased by \sim20% compared to the near-continuum bandpass at 2.20-2.25 mu and in the CO band at 2.3-2.5 mu it is increased by up to \sim50%. The closure phases indicate relatively small deviations from point symmetry close to the photospheric layer, and stronger deviations in the extended H2O and CO layers. Making use of the high spatial and spectral resolution, a near-continuum bandpass can be isolated from contamination by molecular and dusty layers, and the Rosseland-mean photospheric angular diameter is estimated to 11.3 +/- 0.3 mas based on a PHOENIX atmosphere model. Together with recent high-precision estimates of the distance and spectro-photometry, this estimate corresponds to a radius of 1420 +/- 120 Rsun and an effective temperature of 3490 +/- 90 K. VY CMa exhibits asymmetric, possibly clumpy, atmospheric layers of H2O and CO, which are not co-spatial, within a larger elongated dusty envelope. Our revised fundamental parameters put VY CMa close to the Hayashi limit of recent evolutionary tracks of initial mass 25 Msun with rotation or 32 Msun without rotation, shortly before evolving blueward in the HR-diagram.

arXiv comment5 pages, 5 figures, accepted for publication in Astronomy and Astrophysics (A&A) as a Letter

References in corpus (25)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• Interferometric data reduction with AMBER/VLTI.Principle,estimators and illustration
• The mass-loss rates of red supergiants and the de Jager prescription
• Red supergiants as potential Type IIn supernova progenitors: Spatially resolved 4.6 micron CO emission around VY CMa and Betelgeuse
• High-resolution imaging of dust shells using Keck aperture masking and the IOTA Interferometer
• Interferometric observations of the supergiant stars alpha Orionis and alpha Herculis with FLUOR at IOTA
• The 3D Morphology of VY Canis Majoris. I The Kinematics of the Ejecta
• Kinematics of OB-associations and the new reduction of the Hipparcos data
• The last gasps of VY CMa: Aperture synthesis and adaptive optics imagery
• Distance to VY Canis Majoris with VERA
• Near-IR Spectra of Red Supergiants and Giants. I- Models with Solar and with Mixing-Induced Surface Abundance Ratios
• J, H, K spectro-interferometry of the Mira variable S Orionis
• Supergiant Temperatures and Linear Radii from Near-Infrared Interferometry
• Inhomogeneities in molecular layers of Mira atmospheres
• Mid-infrared interferometry on spectral lines: II. Continuum (dust) emission around IRC+10216 and VY CMa
• The molecular envelope around the red supergiant VY CMa
• Study of molecular layers in the atmosphere of the supergiant star mu Cep by interferometry in the K band
• Infrared Spectra and Visibilities as Probes of the Outer Atmospheres of Red Supergiant Stars
• Bringing VY Canis Majoris Down to Size: An Improved Determination of Its Effective Tempeature
• The 3D Morphology of VY Canis Majoris II: Polarimetry and the Line-of-Sight Distribution of the Ejecta
• PACS and SPIRE Spectroscopy of the Red Supergiant VY CMa
• The ISO Long Wavelength Spectrometer line spectrum of VY Canis Majoris and other oxygen-rich evolved stars
• Arcsecond resolution mapping of Sulfur Dioxide emission in the circumstellar envelope of VY Canis Majoris
• Resolving the asymmetric inner wind region of the yellow hypergiant IRC+10420 with VLTI/AMBER in low and high spectral resolution mode

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