Imaging the cool hypergiant nml cygni's dusty circumstellar envelope with adaptive optics

M. T. Schuster, M. Marengo, J. L. Hora, G. G. Fazio, R. M. Humphreys, R. D. Gehrz, P. M. Hinz, M. A. Kenworthy, W. F. Hoffmann

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

We present subarcsecond 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 μm. These images reveal once more the complexity in the dusty envelope surrounding this star. We spatially resolve the physical structures (radius 014, 240 AU adopting a distance of 1.74 kpc) responsible for NML Cyg's deep 10 μm silicate dust absorption feature. We also detect an asymmetric excess, at separations of 03-05 (520-870 AU), northwest 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 to explain the geometry of an inverted photodissociation region observed at optical wavelengths.

Original languageEnglish (US)
Pages (from-to)1423-1432
Number of pages10
JournalAstrophysical Journal
Volume699
Issue number2
DOIs
StatePublished - Jan 1 2009

Keywords

  • Circumstellar matter
  • Infrared: stars
  • Open clusters and associations: individual (Cyg OB2)
  • Stars: imaging
  • Stars: individual (NML Cyg)
  • Stars: mass loss

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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