THEORETICAL HE-I LINE-INTENSITIES IN GASEOUS NEBULAE - NGC-1976, NGC-6572 AND IC-4997

Citation
Jb. Kingdon et Gj. Ferland, THEORETICAL HE-I LINE-INTENSITIES IN GASEOUS NEBULAE - NGC-1976, NGC-6572 AND IC-4997, Monthly Notices of the Royal Astronomical Society, 282(3), 1996, pp. 723-725
Citations number
13
Categorie Soggetti
Astronomy & Astrophysics
ISSN journal
00358711
Volume
282
Issue
3
Year of publication
1996
Pages
723 - 725
Database
ISI
SICI code
0035-8711(1996)282:3<723:THLIGN>2.0.ZU;2-L
Abstract
Smits has recently calculated theoretical He I intensities for a large number of lines for conditions appropriate to gaseous nebulae. These are likely to remain the definitive calculations for some time to come . A comparison of these line ratios with observed values in three nebu lae reveals some discrepancies. We show that these discrepancies are r educed when collisional effects from the metastable 2(3)S level are in cluded, and that it is not necessary to invoke an unknown depopulation mechanism for the He I 2(3)S level.