The populations of planetary nebulae in the direction of the Galactic bulge - Chemical abundances and Wolf-Rayet central stars
The populations of planetary nebulae in the direction of the Galactic bulge - Chemical abundances and Wolf-Rayet central stars
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银河核球方向的行星状星云群 - 化学丰度和沃尔夫-拉叶中心恒星
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发表时间：
2004
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通讯作者：
Roberto Costa
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作者：
S. Górny;G. Stasińska;A. V. Escudero;Roberto Costa
巴西圣保罗市马塔卡路1226号，05508 -090，Geof 'isica e Cie Ncias Atmosfe' ricas da USP，天文研究所，天文系。接受？？？抽象的。我们观测到了44个位于银河系隆起方向的行星状星云，并将我们的数据与已发表的数据进行了合并。在合并的164个PNE样本中，我们区分了那些最有可能物理上属于银河系凸起的PNE和那些最有可能属于银河系盘的PNE。我们已经以一种连贯的方式确定了所有164个物体的化学成分。我们寻找了恒星的发射特征，发现了14颗新的[WR]星和15颗新的弱发射线中心星，分析结果表明：（1）[WR]星的光谱型分布在星系核球和星系盘中有很大差异。然而，观察到的分布强烈依赖于选择效应。(2)[WR]PNe的比例在凸起中明显大于在盘中。(3)[WR]恒星中的氧丰度似乎没有受到核合成和祖先混合的显著影响。(4)银河系圆盘的O/H梯度分布在银河系的最内部。(5)在隆起的PN群体中的中值氧丰度比在隆起方向上观察到的盘群体中的中值氧丰度大0.2dex。(6)O/H越小的凸起PNe径向速度越小。(7)核球PNe的氧丰度分布与核球巨星的金属丰度分布形状相似，但明显窄一些。（8）SB 32（部件编号G 349.7-09.1）在（V）中的位置
Departamento de Astronomia, Instituto de Astronomia, Geof´isica e Cieˆncias Atmosfe´ricas da USP, Rua do Mata˜o 1226,05508-090, Sa˜o Paulo, BrazilReceived ???; accepted ???Abstract. We have observed 44 planetary nebulae (PNe) in the direction of the Galactic bulge, and merged our data withpublished ones. We have distinguished, in the merged sample of 164 PNe, those PNe most likely to prtain physically to theGalactic bulge and those most likely to belong to the Galactic disk. We have determined the chemical composition of all the164 objects in a coherent way. We looked for stellar emission features and discovered 14 new [WR] stars and 15 new weakemission line central stars.The analyzed data led us to the following conclusions: (1) The spectral type distribution of [WR] stars is very different in thebulge and in the disk of the Galaxy. However, the observed distributions are strongly dependent on selection effects. (2) Theproportion of [WR]PNe is significantly larger in the bulge th an in the disk. (3) The oxygen abundances in [WR] stars do noappear to be significantly a ffected by nucleosynthesis and mixing in the progenitors. (4) The O/H gradient of the Galactic diskPNe population flattens in the most internal parts of the Gala xy. (5) The median oxygen abundance in the bulge PN populationis larger by 0.2 dex than in the disk population seen in the direction of the bulge. (6) Bulge PNe with smaller O/H tend tohave smaller radial velocities. (7) The oxygen abundance distribution of bulge PNe is similar in shape to that of the metallicitydistribution of bulge giants, but significantly narrower. ( 8) The location of SB 32 (PN G 349.7-09.1) in the (V