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Results for “costeros”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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3 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

On the He/plus/ triplet line intensities.

Check of the adequacy of theoretical calculations of helium-triplet line strengths, including collisional enhancement, by comparing theoretical prediction with astronomical observations. It is shown that the observations of Peimbert and Torres-Peimbert (1971) and of Peimbert and Costero (1969) fit the theoretical predictions rather well, placing planetary nebulae and H II regions in separate density and temperature ranges. It appears that the theory of helium-triplet line strengths agrees with present observations.

Daltabuit, E.↗
NASA NTRS1975

Photometry of a bright filament in the Orion nebula

The spectrum of a bright filament in the outer portion of the Orion nebula, 14 min from the Trapezium, was studied. The temperature of the filament, derived from /N II/ lambda 5755/6583 ratio, is 9560 K. The electron density (from /S II/ lambda 6717, 6731) is low: 360 plus or minus 150 per cu cm. The ionic abundances of He(+), N(+), O(++), and S(-) are about the same as Peimbert and Costero (1969) found in regions in Orion closer to the Trapezium. It is concluded that the filament is photoionized, presumably by the Trapezium, rather than a shock front, as had originally been suspected.

Dufour, R. J.↗