dc.contributor.author |
Mallik, D. C. V |
|
dc.date.accessioned |
2009-06-22T15:13:10Z |
|
dc.date.available |
2009-06-22T15:13:10Z |
|
dc.date.issued |
1978 |
|
dc.identifier.citation |
Basinska-Grzesik-Grzesik, E and Mayor, M., eds., Chemical and dynamical evolution of our galaxy., Proceedings of the IAU Colloquium No.45 held at the Nicoclaus Copernicus University, Torun, Poland September 7 - 9 1977, pp. 187 - 191 |
en |
dc.identifier.uri |
http://hdl.handle.net/2248/4572 |
|
dc.description.abstract |
The extent of nitrogen enrichment of the interstellar gas by planetary-nebula formation is evaluated, and the nitrogen and oxygen abundance gradients in the disk of the Galaxy are derived on the basis of a simple model for galactic evolution. The double-shell-source lifetime of stars of different initial mass is determined along with the maximum possible number of helium shell flashes for a star of particular mass. CNO production via the shell flashes is examined, the N-14 and O-16 yields for a generation of stars are computed, and the distributions of oxygen and nitrogen in the Galactic disk are obtained. It is found that primary production of N-14 in low-mass stars contributes nearly 50 percent to the total abundance of N-14 in the Galaxy, that the logarithmic abundance gradients in the solar neighborhood are -0.18 for nitrogen and -0.13 for oxygen, and that the gradients are sensitive to the distribution of interstellar gas. |
en |
dc.language.iso |
en |
en |
dc.publisher |
Geneva Observatory |
en |
dc.relation.ispartofseries |
IAU Colloquium; No.45 |
|
dc.relation.uri |
http://adsabs.harvard.edu/abs/1978cdeo.coll..187M |
en |
dc.subject |
Abundance |
en |
dc.subject |
Galactic Evolution |
en |
dc.subject |
Nitrogen |
en |
dc.subject |
Planetary Nebulae |
en |
dc.subject |
Oxygen |
en |
dc.subject |
Stellar Envelopes |
en |
dc.title |
Planetary nebulae and nitrogen enrichment in the galaxy |
en |
dc.type |
Article |
en |