Molecular hydrogen maps of extended planetary nebulae - the Dumbbell, the Ring, and NGC 2346
The 3.8-m United Kingdom Infrared Telecsope at Mauna Kea was used to obtain complete H2 maps of three extended planetary nebulae (PNs) that are representative of two of the most common PN morphologies, bow tie and bipolar ring: the Dumbbell (NGC 6853), the Ring (NGC 6720), and the NG 2346, are discussed. The results of map analysis indicates that the S(1) emission from H2 closely follows the optical morphology of the three nebulae. The H2 emission is more extended than the main emitting mass of ionized gas and, in NGCC 2346, there is evidence for a dense torus of hot H2 surrounding the central star. The H2 emissionl appears to be shock-excited. Examinations of existing H2 measurements indicate that strong H2 emission is preferentially present in PNs that lie at small galactic latitude, implying that massive main-sequence stars produce ionization-bounded PNs, whereas low-mass stars produce density-bounded PNs. Thus, maps of H2 emission may not only be used to determine whether a given PN is ionization-bounded or density-bounded, but also to estimate the mass of the progenitor star. 83 references.
- Research Organization:
- California Univ., Los Angeles (USA); National Optical Astronomy Observatories, Tucson, AZ (USA)
- OSTI ID:
- 5345972
- Journal Information:
- Astrophys. J.; (United States), Vol. 324
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
PLANETARY NEBULAE
MAPS
DENSITY
EMISSION SPECTRA
H2 REGIONS
INTERPLANETARY MAGNETIC FIELDS
IONIZED GASES
MASS
MORPHOLOGY
SPATIAL DISTRIBUTION
STAR EVOLUTION
STELLAR WINDS
COSMIC RADIO SOURCES
DISTRIBUTION
FLUIDS
GASES
MAGNETIC FIELDS
NEBULAE
PHYSICAL PROPERTIES
SPECTRA
STELLAR ACTIVITY
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources