Galactic Planetary Nebulae with Wolf-Rayet Nuclei III: Kinematical Analysis of a Large Sample of Nebulae
Expansion velocities (Vexp) of different ions and line widths at the base of the lines are measured and analyzed for 24 PNe with [WC]-type nuclei (WRPNe), 9 PNe ionized by WELS (WLPNe) and 14 ordinary PNe. A comparative study of the kinematical behavior of the sample clearly demonstrates that WRPNe have on average 40-45% larger Vexp, and possibly more turbulence than WLPNe and ordinary PNe. WLPNe have velocity fields very much like the ones of ordinary PNe, rather than the ones of WRPNe. All the samples (WRPNe, WLPNe and ordinary o PNe) show expansion velocities increasing with age indicators, for example <Vexp> is larger for low-density nebulae and also it is larger for nebulae around high temperature stars. This age effect is much stronger for evolved WRPNe, suggesting that the [WC] winds have been accelerating the nebulae for a long time, while for non-WRPNe the acceleration seems to stop at some point when the star reaches a temperature of about 90,000 - 100,000 K. Non-WR nebulae reach a maximum Vexp ≤ 30 kms-1 while evolved WRPNe reach maximum Vexp of about 40 kms-1. For all kinds of objects (WRPNe and non-WRPNe) it is found that on average Vexp(N+) is slightly larger than Vexp(O++), indicating that the nebulae present acceleration of the external shells.
| Main Authors: | , , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Universidad Nacional Autónoma de México, Instituto de Astronomía
2006
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| Online Access: | http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-11012006000100007 |
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