Mid-infrared interferometry on spectral lines: II. Continuum (dust) emission around IRC+10216 and VY CMa

Abstract

The U. C. Berkeley Infrared Spatial Interferometer has measured the mid-infrared visibilities of the carbon star IRC+10216 and the red supergiant VY CMa. The dust shells around these sources have been previously shown to be time-variable, and these new data are used to probe the evolution of the dust shells on a decade time-scale, complementing contemporaneous studies at other wavelengths. Self-consistent, spherically-symmetric models at maximum and minimum light both show the inner radius of the IRC+10216 dust shell to be much larger (150 mas) than that expected from the dust condensation temperature, implying that dust production has slowed or stopped in recent years. Apparently, dust does not form every pulsational cycle (638 days), and these mid-infrared results are consistent with recent near-IR imaging which indicates little or no new dust production in the last three years (Tuthill et al 2000). Spherically symmetric models failed to fit recent VY CMa data, implying that emission from the inner dust shell is highly asymmetric and/or time-variable.

18 pages, Accepted in the Astrophysical Journal

References in corpus (5)

• The last gasps of VY CMa: Aperture synthesis and adaptive optics imagery
• Mid-infrared interferometry on spectral lines: III. Ammonia and Silane around IRC+10216 and VY CMa
• Temporal Variations of Mid-IR Spectra in Late-Type Stars
• Non-Uniform Outflow Observed around Infrared Object NML Cygni
• Mid-infrared spectra of late-type stars: Long-term evolution

Cited by in corpus (23)

• Optical Interferometry in Astronomy
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• A Detailed Analysis of the Dust Formation Zone of IRC+10216 Derived from Mid-IR Bands of C2H2 and HCN
• Molecular shells in IRC+10216: tracing the mass loss history
• Fundamental properties and atmospheric structure of the red supergiant VY CMa based on VLTI/AMBER spectro-interferometry
• Mid-infrared interferometry on spectral lines: III. Ammonia and Silane around IRC+10216 and VY CMa
• New insights into the dust formation of oxygen-rich AGB stars
• Comparative Spectra of Oxygen-Rich vs. Carbon-Rich Circumstellar Shells: VY Canis Majoris and IRC+10216 at 215-285 GHz
• Si-bearing molecules towards IRC+10216: ALMA unveils the molecular envelope of CWLeo
• Submillimeter narrow emission lines from the inner envelope of IRC+10216
• The complex dust formation zone of the AGB star IRC+10216 probed with CARMA 0.25 arcsec angular resolution molecular observations
• Mid-infrared interferometric monitoring of evolved stars - The dust shell around the Mira variable RR Aql at 13 epochs
• Multi-wavelength diffraction-limited imaging of the evolved carbon star IRC +10216, II
• Circumstellar ammonia in oxygen-rich evolved stars
• Atmospheric molecular blobs shape up circumstellar envelopes of AGB stars
• The maser emitting structure and time variability of the SiS lines J=14-13 and 15-14 in IRC+10216
• Simultaneous VLBA polarimetric observations of the v={1,2} J=1-0 and v=1, J=2-1 SiO maser emission toward VY CMa: maser morphology and pumping
• SiS in the circumstellar envelope of IRC +10126: maser and quasi-thermal emission
• An accreting dwarf star orbiting the S-type giant star pi1 Gru
• Four Decades of IRC +10216: Evolution of a Carbon Rich Dust Shell Resolved at 10 microns with MMT Adaptive Optics and MIRAC4
• From the atmosphere to the circumstellar environment in cool evolved stars