HM Sagittae as a young planetary nebula

Journal Article · Sun Apr 01 04:00:00 EST 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156944· OSTI ID:6217633

Kwok, S; Purton, C R

HM Sagittae is suggested to be a very young planetary nebula recently transformed from a red-giant star through continuous mass loss. The observational data for HM Sge have been analyzed in terms of the interacting stellar wind model of planetary nebula formation. The model is in accord with virtually all the spectral data available--radio, optical, and infrared--as well as with the remarkable brightening of HM Sge observed in 1975. In particular, all three gaseous components predicted by the model are observed in the optical spectrum. The density in the newly formed shell is found to be at least 5 x 10/sup 7/ cm/sup -3/, a value considerably higher than that found by the conventional analysis, which assumes a single-component homogeneous nebula. The radio spectrum is dominated by free-free emission from the remnant red-giant wind. The infrared spectrum suggests the presence of two dust components, one consisting of silicate grains left over from the red-giant stage and the other of grains newly formed after the 1975 brightening. The low observed shell mass is consistent with the interacting stellar wind model but is not consistent with the conventional sudden-ejection model of planetary nebula formation.

• Research Organization: CRESS, York University, Toronto
• OSTI ID: 6217633
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 229:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC DUST
DUSTS
ELECTROMAGNETIC RADIATION
ENERGY SPECTRA
GIANT STARS
INFRARED SPECTRA
MATHEMATICAL MODELS
NEBULAE
PLANETARY NEBULAE
RADIATIONS
RADIOWAVE RADIATION
RED GIANT STARS
SPECTRA
STAR EVOLUTION
STAR MODELS
STARS
STELLAR WINDS
VISIBLE SPECTRA