Optical line intensities in the Trifid nebula

Journal Article · Mon Jul 01 04:00:00 EDT 1985 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/163325· OSTI ID:5573351

Lynds, B T; Oneil, Jr, E J

Observations of the Trifid nebula (M20) obtained in H-alpha; He I (587.6 nm); and the forbidden lines of N II (658.3 nm), S II (671.6 and 673 nm), O III (500.7 nm), and O II (272.6 and 372.9 nm) using either the CIT long-slit spectrograph or a direct-mode CCD with narrow-band interference filters on the 92-cm telescope at KPNO are reported. The data are presented in extensive graphs and characterized in detail and a model is proposed to explain the scattering measurements. Findings discussed include a single central O7 V star with Teff = about 37,500 K, a dusty plasma ionized by this star, mean nebular electron density 150/cu cm, a central hole of radius 0.2 times that of the ionized zone, dust extending beyond the ionized region, overall temperature 7000-8000 K, filament temperatures up to 9000 K, dust optical depth 1.5 at H-beta, dust albedo 0.5, emission-nebula radius 2.8 pc, and total mass about 1700 solar mass (comprising 340 solar mass ionized material, about 800 solar mass unionized cloud material, and about 600 solar mass in an outer dust sphere). 18 references.

• Research Organization: Kitt Peak National Observatory, Tucson, AZ
• OSTI ID: 5573351
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 294; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALBEDO
ELECTRON DENSITY
EMISSION SPECTRA
EMISSION SPECTROSCOPY
FLUIDS
FLUX DENSITY
GASES
INTERSTELLAR SPACE
IONIZED GASES
NEBULAE
RADIANT FLUX DENSITY
SPACE
SPECTRA
SPECTROSCOPY