2009ApJ...696..729M -
Astrophys. J., 696, 729-740 (2009/May-1)
The planetary nebula population of M33 and its metallicity gradient: a look into the galaxy's distant past.
MAGRINI L., STANGHELLINI L. and VILLAVER E.
Abstract (from CDS):
The planetary nebula (PN) population of M33 is studied via multifiber spectroscopy with Hectospec at the MMT. In this paper, we present the spectra of 102 PNe, whereas plasma diagnostic and chemical abundances were performed on the 93 PNe where the necessary diagnostic lines were measured. About 20% of the PNe are compatible with being Type I; the rest of the sample is the progeny of an old disk stellar population, with main sequence masses M < 3 M☉ and ages t > 0.3 Gyr. By studying the elemental abundances of the PNe in the M33 disk, we were able to infer that (1) there is a tight correlation between O/H and Ne/H, broadly excluding the evolution of oxygen; (2) the average abundances of the α-elements are consistent with those of H II regions, indicating a negligible global enrichment in the disk of M33 from the epoch of the formation of the PN progenitors to the present time; and (3) the radial oxygen gradient across the M33 disk has a slope of -0.031±0.013 dex/kpc, in agreement, within the errors, with the corresponding gradient derived from H II regions. Our observations do not seem to imply that the metallicity gradient across the M33 disk has flattened considerably with time. We report also the discovery of a PN with Wolf-Rayet features, PN039, belonging the class of late [WC] stars.
Abstract Copyright:
∼
Journal keyword(s):
galaxies: abundances - galaxies: evolution - galaxies: individual: M33 - planetary nebulae: general
VizieR on-line data:
<Available at CDS (J/ApJ/696/729): table1.dat table2.dat table3.dat>
Nomenclature:
Table 1: [MSV2009] NNN (Nos 153-156).
Simbad objects:
106
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2009ApJ...696..729M and select 'bookmark this link' or equivalent in the popup menu