The chemical composition of the galactic H II region M17.
Abstract
Spectrophotometry in the 3400 - 7400 Å range is presented for 17 areas of the H II region M17. The observations were obtained at KPNO and CTIO with the 2.1-m and the 4-m telescopes respectively. Based on these observations the chemical composition is derived. The logarithmic abundances by number of the gaseous component for t2 = 0.00 are: H = 12.00, He = 11.02, C = 8.74, N = 7.71, 0 = 8.51, Ne = 7.80, 5 = 6.99, Cl = 5.18, Ar = 6.38, and Fe = 6.62; while for t2 - 0.04 are: H = 12.00, He = 11.00, C = 8.73, N = 8.01, 0 = 8.81, Ne = 8.13,5 = 7.32, Cl = 5.48, Ar = 6.63 and Fe = 6.94. The C abundance gradient in the Galaxy derived from the Orion nebula and M17 is of -0.08+0.02 dex . The AY/AZ ratio derived from the primordial helium abundance and the M17 values amounts to 4.47 for t2 - 0.00 and to 2.50 for t2 - 0.04.
- Publication:
-
Revista Mexicana de Astronomia y Astrofisica
- Pub Date:
- October 1992
- Bibcode:
- 1992RMxAA..24..155P