Faint emission lines in the Orion Nebula: C and O abundances
Por:
Esteban C., Peimbert M., Torres-Peimbert S., Escalante V.
Publicada:
1 ene 1995
Resumen:
We present preliminary results on the analysis of echelle spectra of the Orion Nebula taken at 45? N of ?1 Ori C and covering from 3700 to 6750 Å. The data were obtained using the 2.1-m telescope at the Observatorio Astronómico Nacional in San Pedro Mártir, B.C. We have detected and measured several faint permitted lines of O0, O+, C+, S+, N+, Si+ and Si++ which are excited by electron recombination and/or fluorescence. The S/N ratio and spectral resolution of the data are adequate to allow the derivation of O++/H+ using several lines and avoiding the problem of line blending. The O++/H+ abundance obtained from recombination lines is 40% higher than that derived using forbidden [O III] lines from the same spectrum. On the other hand, the C++/H + value derived using the permitted C II ?4267 line is a factor of 3 higher than that quoted in previous work for the same zone using C III] ??1906+1909 emission lines. We estimate that a moderate value of t2=0.025±0.015 can account for these discrepancies. © Universidad Nacional Autónoma de México.
Filiaciones:
Esteban C.:
Instituto de Astrofisica de Canarias, 38200 La Laguna, Tenerife, Spain
Peimbert M.:
Instituto de Astronomía, UNAM, Apdo. Postal 70-264, 04510 México D.F., Mexico
Torres-Peimbert S.:
Instituto de Astronomía, UNAM, Apdo. Postal 70-264, 04510 México D.F., Mexico
Escalante V.:
Instituto de Astronomía, UNAM, Apdo. Postal 70-264, 04510 México D.F., Mexico
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