Bibcode
Dobrinčić, Martina; Villaver, Eva; Guerrero, Martín A.; Manchado, A.
Bibliographical reference
The Astronomical Journal, Volume 135, Issue 6, pp. 2199-2211 (2008).
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6
2008
Citations
19
Refereed citations
19
Description
We present the kinematics of a sample of bipolar planetary nebulae (PNs)
which cover a wide range of observed morphologies and collimation
degrees, from bipolar PNs (BPNs) with a marked equatorial ring and wide
lobes to highly collimated objects. We use an empirical model in order
to derive the expansion velocity, collimation degree, and inclination
angle of the PN with respect to the plane of the sky. The equatorial
expansion velocities measured in the objects in our sample are always in
the low-to-medium range (3-16 km s-1), while their polar
expansion velocities range from low to very high (18-100 km
s-1). None of the objects in our sample, even those that show
an extreme collimation degree, seem to be (kinematically) younger than
sime103 yr. We compare our results with the state-of-the-art
theoretical models for the formation of BPNs. We find good agreement
between the observed expansion velocities and numerical models that use
magnetic fields with stellar rotation as a collimation mechanism.
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