SIMBAD references

1997A&A...323..442W - Astronomy and Astrophysics, volume 323, 442-448 (1997/7-2)

The nature of the unusual source IRAS 18530+0817.

WALKER H.J., TSIKOUDI V., CLAYTON C.A., GEBALLE T., WOODEN D.H. and BUTNER H.M.

Abstract (from CDS):

Infrared photometry and spectroscopy of the unassociated (infrared-only) IRAS source, IRAS 18530+0817, indicate that it is a highly unusual evolved star surrounded by a dense envelope of cool gas and dust. The IRAS data reveal a large infrared excess and significant flux variability in the 12-25µm region, as well as a prominent, silicate emission feature at 8.5-11.5µm. The shape of the feature also appears to vary; in 1993 it was apparently attenuated by an absorption with a sharp edge at 9.5µm, which may be circumstellar or photospheric in origin. At other times the silicate feature appears to be self-absorbed by varying amounts. Near-infrared spectra of IRAS 18530+0817 are dominated by steam absorptions, with the K-band spectrum showing only a narrow band of relatively unabsorbed continuum at 2.15-2.29µm. The object appears to possess the strongest stellar photospheric H2O absorptions yet observed. We tentatively conclude that the central star of IRAS 18530+0817 is a late-type, O-rich, AGB star (a Mira variable) surrounded by an envelope of O-rich dust.

Abstract Copyright:

Journal keyword(s): circumstellar matter - stars: individual: IRAS 18530+0817 - stars: evolution - stars: mass-loss - stars: AGB and post-AGB - infrared: stars

Simbad objects: 4

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