Far-infrared study of N/O abundance ratio in galactic H 2 regions
Technical Report
·
OSTI ID:6049422
Far-infrared lines of N++ and O++ in several galactic H II regions were measured in an effort to probe the abundance ratio N/O. New measurements are presented for W32 (630.8-0.0), Orion A, and G75.84+0.4. The combination of (N III) 57.3 millimicrons and (O III) 88.4 and 51.8 millimicrons yields measurements of N++/O++ that are largely insensitive to electron temperature, density uncertainties, and to clumping of the ionized gas, due to the similarity of the critical densities for these transitions. In the observed nebulae, N++/O++ should be indicative of N/O, a ratio that is of special importance in nucleosynthesis theory. Measurements are compared with previous measurements of M17 and W51. For nebulae in the solar circle, N++/O++ is greater than the N/O values derived from optical studies of N+/O+ in low ionization zones of the same nebulae. We find that N++/O++ in W43 is significantly higher than for the other H II regions in the sample. Since W43 is located at R 5 kpc, which is the smallest galactocentric distance in our sample, our data appear consistent with the presence of a negative abundance gradient d(N/O)dR.
- Research Organization:
- National Aeronautics and Space Administration, Moffett Field, CA (USA). Ames Research Center
- OSTI ID:
- 6049422
- Report Number(s):
- N-8320874; NASA-TM-84331; A-9524
- Country of Publication:
- United States
- Language:
- English
Similar Records
Far-infrared (OIII) and (NIII) line emission from galactic H II regions and planetary nebulae
Far-infrared measurements of N/O in H II regions - evidence for enhanced CN process nucleosynthesis in the inner Galaxy
The 51. 8 micrometer (O III) line emission observed in four galactic H2 regions. [M42, M17, W51, NGC 6375A]
Journal Article
·
Sat Nov 14 19:00:00 EST 1981
· Astrophys. J.; (United States)
·
OSTI ID:5655375
Far-infrared measurements of N/O in H II regions - evidence for enhanced CN process nucleosynthesis in the inner Galaxy
Journal Article
·
Tue Sep 01 00:00:00 EDT 1987
· Astrophys. J.; (United States)
·
OSTI ID:5662666
The 51. 8 micrometer (O III) line emission observed in four galactic H2 regions. [M42, M17, W51, NGC 6375A]
Technical Report
·
Tue Aug 01 00:00:00 EDT 1978
·
OSTI ID:5905640
Related Subjects
640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTIVITY
ABUNDANCE
CHARGED PARTICLES
ELECTRON DENSITY
ENERGY LEVELS
FABRY-PEROT INTERFEROMETER
FLUIDS
GASES
GROUND STATES
INFRARED SPECTRA
INTERFEROMETERS
INTERSTELLAR SPACE
IONIZED GASES
IONS
ISOTOPES
LUMINOSITY
MEASURING INSTRUMENTS
NEBULAE
NITROGEN IONS
NITROGEN ISOTOPES
NUCLEAR REACTIONS
NUCLEOSYNTHESIS
OPTICAL PROPERTIES
OXYGEN IONS
OXYGEN ISOTOPES
PHYSICAL PROPERTIES
QUANTITY RATIO
SPACE
SPECTRA
THERMONUCLEAR REACTIONS
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTIVITY
ABUNDANCE
CHARGED PARTICLES
ELECTRON DENSITY
ENERGY LEVELS
FABRY-PEROT INTERFEROMETER
FLUIDS
GASES
GROUND STATES
INFRARED SPECTRA
INTERFEROMETERS
INTERSTELLAR SPACE
IONIZED GASES
IONS
ISOTOPES
LUMINOSITY
MEASURING INSTRUMENTS
NEBULAE
NITROGEN IONS
NITROGEN ISOTOPES
NUCLEAR REACTIONS
NUCLEOSYNTHESIS
OPTICAL PROPERTIES
OXYGEN IONS
OXYGEN ISOTOPES
PHYSICAL PROPERTIES
QUANTITY RATIO
SPACE
SPECTRA
THERMONUCLEAR REACTIONS