Planetary nebulae morphologies, central star masses and nebular properties.
Gorny S.K., Stasinska G. & Tylenda R.
1996, A&A 318, 256
Abstract:
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We have constituted a sample of about 80 PN with defined morphologies and
well observed basic parameters (fluxes, angular radii, expansion velocities
and magnitudes of the central stars). For these PN, we have derived the
central star masses by comparing the observed set of parameters with those
predicted by a simple evolutionary model of a PN, expanding at the same
velocity as the observed one. We have then examined the relations between
the PN morphological types and other properties, linked to the central star
mass.
Bipolar PN are shown to have a wider distribution of central star masses
than the rest of PN, and shifted towards higher values. They lie closer to
the Galactic plane and tend to have larger N/O ratios.
Point symmetric PN, which have not been much studied so far, are found to
constitute an outstanding class. They show an almost perfect M - v correlation. They correspond to a rather short
evolutionary stage of PN. They lie, on average, further from the Galactic
plane than bipolar PN and tend to have lower N/O.
Globally, PN with higher central star masses are found closer to the
Galactic plane, and the observed relation between N/O and M is roughly consistent with the
predictions from evolutionary models for AGB stars.
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