[Previous] | [Session 22] | [Next]
M. A. Guerrero, Y.-H. Chu (UIUC), L. F. Miranda (Instituto de Astrof\a'{i}sica de Andaluc\a'{i}a)
Planetary nebulae (PNe) show a large variety of morphologies, not only in the overall shape of the nebula, but also in additional features such as jets and ansae. It has been suggested that these morphologies and features are produced by binary PN central stars (CSPNs), but a very small number of binary CSPNs are known because CSPNs are very luminous and may overwhelm their companions even at near IR wavelengths.
The nebular morphology can be used to search for imprints of binary CSPNs. The nebular features that present the most suggestive evidence of actions of binary CSPNs are curved strings of knots showing reflection symmetry with respect to the central star. Such point-symmetric features in PNe have been associated with precessing collimated outflows. Since the collimation and precession of these outflows can be most readily produced by a binary CSPN, the physical properties of point-symmetric outflows in PNe can be used to investigate the nature of binary systems in CSPNs.
We have used observations of the kinematics of point-symmetric collimated outflows of a number of PNe to determine the 3-D structure of the outflows. These have been used to derive the history of the outflow and mass-loss, and to constrain the orbital periods and separations of binary CSPNs. The observations also provide evidence of the interaction of collimated outflows with the nebular shell that has allowed us to assess the effects of collimated outflows in the shaping of PNe.
[Previous] | [Session 22] | [Next]
Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.