FM4.5.01 — The planetary nebulae in NGC6822 revisited

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Aug 6th at 10:30 AM until 10:50 AM

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Author(s): Miriam Pena2, Jorge Garcia-Rojas1, Sheila Flores-Duran2, Liliana Hernandez-Martinez2

Institution(s): 1. Instituto de Astrofisica de Canarias, 2. Universidad Nacional Autonoma de Mexico

Spectroscopic data for 20 PNe in the irregular galaxy NGC6822 have been studied. This represents 80% of the total sample of PNe candidates in this galaxy. We discuss the kinematics of PNe in comparison to the kinematics of the HI disk and the young and intermediate age populations. In addition the chemical abundances of the sample have been analyzed. We found that PNe can be separated in two groups: one older, with 12+log O/H abundances lower than 7.8 and other young, with abundances similar to the values of HII regions (12+log O/H of about 8.1). The old objets are more widely distributed than the young ones. In our sample, a large fraction of PNe (near 30%) can be classified as Peimbert Type I objects, fraction that is much larger than in our galaxy. Many of our PNe are highly ionized, showing an abundance fraction He++/He larger than 0.1. From the HeII 4686 A emission line we have determined temperatures for the central stars founding that half of them show T larger than 100000 K. These result are being analyzed in terms of the possible populations for the PN sample.