A principal component analysis approach to the morphology of Planetary nebula

Authors
Abstract:
Principal Component Analysis (PCA) is a well-known technique used to decorrelate a set of vectors. It has been applied to explore the star formation history of galaxies or to determine distances of mass-lossing stars. Here we apply PCA to the optical data of Planetary Nebulae (PNe) with the aim of extracting information about their morphological differences. Preliminary analysis of a sample of 55 PNe with known abundances and morphology shows that the second component (PC2), which results from a relation produced by the parameters log(N/O), initial and final mass of PNe, is depending on the morphology of PNe. It has been found that when log(N/O) < -0.18 the PNe's nitrogen is low independently on the oxygen abundance for either Bipolar (B), Elliptical (E) or Round (R) PNe. An interesting result is that both E and R PNe have log(N/O) < 0 while only B PNe show negative and positive values. Consequently, B PNe are expected to have higher nitrogen values than the E and R PNe. Also, in all PNe morphologies PC2 appears to have a minimum at 0.89 and PNe's initial mass at 2.6 M$_{\odot}$. 3-D diagrams between PCA's components and abundances are also presented. More results will follow while simple models will be applied in order to try to give physical meaning to the components.
Session:
Presentation Type:
Poster
Contact Name:
Akras Stavros
Email:
arkas@astro.noa.gr
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