AAS 196th Meeting, June 2000
Session 43. Planetary Nebulae and Their Progenitors
Display, Wednesday, June 7, 2000, 10:00am-7:00pm, Empire Hall South

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[43.02] Multiple Collimated Outflows in Frosty Leo, a Bipolar Protoplanetary Nebula

R. Sahai (Jet Propulsion Laboratory/ Caltech), V. Bujarrabal, A. Castro-Carrizo (Observatorio Astronomico Nacional, Alcala de Henares, Spain)

We present high-resolution HST/WFPC2 imaging and millimeter-wave line observations with the IRAM 30m telescope, of the bipolar protoplanetary nebula, Frosty Leo (IRAS09371+1212). Our WFPC2 images show the presence of multiple jet-like features in the inner regions of Frosty Leo; substructures within these features indicate temporal variations in the jets. The images reveal a tenuous bipolar bubble-like structure for the extended nebula, and resolve the equatorial waist of the nebula into a flaring edge-on disk. Two bright structures appear embedded within the bubbles on either side of the waist, and are most likely dense-walled, optically-thick cavities. The polar ansae at the tips of the extended bipolar lobes are found to have a knotty, extended morphology suggesting that they are the result of a polar jet which varies both its direction and intensity with time. The CO and 13CO J=1-0 and 2-1 line observations show the presence of slow (~10 km s-1) and fast (~50 km s-1) components in the molecular outflow. The ratio of the mechanical momentum in the bipolar outflow to the radiative momentum (L/c) is very large, indicating that the excess momentum may be associated with binarity. Although ground-based adaptive optics imaging apparently shows a binary star at the center of Frosty Leo, the binary separation (190 AU at a minimum distance of 1 kpc) is too large for the formation of an accretion disk which could power collimated outflows. [EOB]

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The author(s) of this abstract have provided an email address for comments about the abstract: Raghvendra.Sahai@jpl.nasa.gov

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