Imaging the Cool Hypergiant NML Cygni's Dusty Circumstellar Envelope with Adaptive Optics

Abstract

We present sub-arcsec angular resolution, high-Strehl ratio mid-IR adaptive optics images of the powerful OH/IR source and cool hypergiant NML Cyg at 8.8, 9.8 and 11.7 um. These images reveal once more the complexity in the dusty envelope surrounding this star. We spatially resolve the physical structures (radius ~0.14", ~240 AU adopting a distance of 1.74 kpc) responsible for NML Cyg's deep 10 um silicate dust absorption feature. We also detect an asymmetric excess, at separations of ~0.3" to 0.5" (~520 to 870 AU), NW from the star. The colors of this excess are consistent with thermal emission of hot, optically thin dust. This excess is oriented in the direction of the Cyg OB2 stellar association, and is likely due to the disruption of NML Cyg's dusty wind with the near-UV radiation flux from the massive hot stars within Cyg OB2. This interaction was predicted in our previous paper (Schuster et al. 2006), to explain the geometry of an inverted photo-dissociation region observed at optical wavelengths.

Accepted for publication on The Astrophysical Journal

References in corpus (15)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• The Spitzer Space Telescope Mission
• Drizzle: A Method for the Linear Reconstruction of Undersampled Images
• High-resolution imaging of dust shells using Keck aperture masking and the IOTA Interferometer
• The 3D Morphology of VY Canis Majoris. I The Kinematics of the Ejecta
• Classification of 2.4-45.2 Micron Spectra from the ISO Short Wavelength Spectrometer
• The Circumstellar Environments of NML Cyg and the Cool Hypergiants
• High Resolution, Long - Slit Spectroscopy of VY CMa: The Evidence for Localized High Mass Loss Events
• Non-Uniform Outflow Observed around Infrared Object NML Cygni
• M33's Variable A -- A Hypergiant Star More Than 35 Years in Eruption
• A Spitzer/IRAC Search for Substellar Companions of the Debris Disk Star epsilon Eridani
• The 3D Morphology of VY Canis Majoris II: Polarimetry and the Line-of-Sight Distribution of the Ejecta
• Spatially extended K I 7699 emission in the nebula of VY CMa: Kinematics and geometry
• Bispectrum speckle interferometry observations and radiative transfer modelling of the red supergiant NML Cyg: Multiple dust-shell structures evidencing previous superwind phases
• Excited-state OH Mainline Masers in AU Geminorum and NML Cygni

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