Resolving the Dusty Circumstellar Structure of the Enigmatic Symbiotic Star CH Cygni with the MMT Adaptive Optics System

Abstract

We imaged the symbiotic star CH Cyg and two PSF calibration stars using the unique 6.5m MMT deformable secondary adaptive optics system. Our high-resolution (FWHM=0.3"), very high Strehl (98%+-2%) mid-infrared (9.8 and 11.7 um) images of CH Cyg allow us to probe finer length scales than ever before for this object. CH Cyg is significantly extended compared to our unresolved PSF calibration stars (Mu UMa and Alpha Her) at 9.8 and 11.7 um. We estimated the size of the extension by convolving a number of simple Gaussian models with the Mu UMa PSF and determining which model provided the best fit to the data. Adopting the Hipparcos distance for this object of 270 pc, we found a nearly Gaussian extension with a FWHM at 9.8 um of ~40.5+-2.7 AU (0.15+-0.01") and a FWHM at 11.7 um of 45.9+-2.7 AU (0.17+-0.01"). After subtracting out the Gaussian component of the emission (convolved with our PSF), we found a faint \~0.7" asymmetric extension which peaks in flux ~0.5" north of the stars. This extension is roughly coincident with the northern knotlike feature seen in HST WFPC2 images obtained in 1999.

arXiv comment18 pages, 7 figures, accepted by the Astrophysical Journal

References in corpus (7)

• An X-Ray Jet from a White Dwarf - Detection of the Collimated Outflow from CH Cygni with Chandra
• The symbiotic star CH Cygni. I. Non-thermal bipolar jets
• CH Cygni I: Observational Evidence for a Disk-Jet Connection
• The large-scale ionised outflow of CH Cygni
• Mid-Infrared Imaging of the Post-AGB Star AC Herculis with the MMT Adaptive Optics System
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• High Resolution Mid - Infrared Imaging of the AGB Star RV Boo with the Steward Observatory Adaptive Optics System

Cited by in corpus (12)

• CH Cyg X-ray Jet Activity and Multi-component Structures
• Infrared Spectroscopy of Symbiotic Stars. VII. Binary Orbit and Long Secondary Period Variability of CH Cygni
• A Precessing Jet in the CH Cyg Symbiotic System
• A search for southern ultracool dwarfs in young moving groups
• The spectral energy distribution of D-type symbiotic stars: the role of dust shells
• Silicates in D-type symbiotic stars: an ISO overview
• A Review of AGB Mass Loss Imaging Techniques
• Spectroscopy of the symbiotic star CH Cygni from 1996 to 2007
• Detection of non-radial pulsation and faint companion in the symbiotic star CH Cyg
• Four Decades of IRC +10216: Evolution of a Carbon Rich Dust Shell Resolved at 10 microns with MMT Adaptive Optics and MIRAC4
• The symbiotic star CH Cygni. I. An analysis of the shocked nebulae at different epochs
• Photometry of Symbiotic Stars - XIV