Resolving the dusty circumstellar structure of the enigmatic symbiotic star CH Cygni with the MMT adaptive optics system

Beth A. Biller, Laird M Close, Aigen Li, Massimo Marengo, John H Bieging, Philip M Hinz, William F. Hoffmann, Guido Brusa, Doug Miller

Research output: Contribution to journalArticle

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Abstract

We imaged the symbiotic star CH Cyg and two PSF calibration stars using the unique 6.5 m MMT deformable secondary adaptive optics system. Our high-resolution (FWHM = 0″.3), very high Strehl (98% ± 2%), mid-infrared (9.8 and 11.7 μm) 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 (μ UMa and α Her) at 9.8 and 11.7 μm. We estimated the size of the extension by convolving a number of simple Gaussian models with the μ 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 μm of ∼40.5 ± 2.7 AU (0″.15 ± 0″.01) and a FWHM at 11.7 μm 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.

Original languageEnglish (US)
Pages (from-to)464-470
Number of pages7
JournalAstrophysical Journal
Volume647
Issue number1 I
DOIs
StatePublished - Aug 10 2006

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symbiotic stars
adaptive optics
methylidyne
stars
calibration
probe
probes
high resolution

Keywords

  • Binaries: close
  • Instrumentation: adaptive optics
  • Stars: evolution
  • Stars: formation

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Resolving the dusty circumstellar structure of the enigmatic symbiotic star CH Cygni with the MMT adaptive optics system. / Biller, Beth A.; Close, Laird M; Li, Aigen; Marengo, Massimo; Bieging, John H; Hinz, Philip M; Hoffmann, William F.; Brusa, Guido; Miller, Doug.

In: Astrophysical Journal, Vol. 647, No. 1 I, 10.08.2006, p. 464-470.

Research output: Contribution to journalArticle

Biller, Beth A. ; Close, Laird M ; Li, Aigen ; Marengo, Massimo ; Bieging, John H ; Hinz, Philip M ; Hoffmann, William F. ; Brusa, Guido ; Miller, Doug. / Resolving the dusty circumstellar structure of the enigmatic symbiotic star CH Cygni with the MMT adaptive optics system. In: Astrophysical Journal. 2006 ; Vol. 647, No. 1 I. pp. 464-470.
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