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M. A. Guerrero (UIUC), L. F. Miranda (Instituto de Astrof\a'{i}sica de Andaluc\a'{i}a), Y.-H. Chu (UIUC)
The ant-like nebula Mz\,3 has perhaps the most stunning morphology among all planetary nebulae. Recent spectra and IR photometry of its central star indicate that it might be a symbiotic star, casting doubts on its nature as a planetary nebula. Mz\,3 is composed of several nested pairs of bipolar lobes that suggest the action of episodic bipolar ejections. In order to study the kinematics and derive the de-projected expansion velocity of the different bipolar structures present in this nebula, we have observed Mz\,3 with the CTIO 4m echelle spectrograph in the long-slit mode. These observations reveal four pairs of rapidly expanding (V\rm exp up to 350 km~s-1) lobes corresponding to the morphological features observed in HST images. The four pairs of lobes in Mz\,3 share the same axis of symmetry, but have vastly different expansion velocities and opening angles. Close examination shows that each pair of lobes is characterized by distinct dynamical and physical structures. We use this spatio-kinematical information to determine whether the different pairs of lobes in Mz\,3 were formed at the same time in an explosive event, or produced by episodic bipolar ejections. The formation mechanism of Mz\,3 can help us understand the origin and nature of this spectacular nebula.
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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.