A collimated, high-speed outflow from the dying star V Hydrae |
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Authors: | Sahai R Morris M Knapp G R Young K Barnbaum C |
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Affiliation: | Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109, USA. raghvendra.sahai@jpl.nasa.gov |
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Abstract: | Stars with masses in the range 1-8 solar masses (M(circ)) live ordinary lives for approximately 10(9)-10(10) years, but die extraordinary deaths. First, during their death throes as asymptotic giant branch (AGB) stars they eject, over 10(4)-10(5) years, half or more of their mass in slowly expanding, spherical winds, and then, in a short (a few 100-1,000 years) and poorly understood phase, they are transformed into aspherical planetary nebula. Recent studies support the idea that high-speed, jet-like flows play a crucial role in this transformation. Evidence for such outflows is indirect, however; this phase is so short that few nearby stars are likely to be caught in the act. Here we report the discovery of a newly launched, high-speed jet-like outflow in the nearby AGB star, V Hydrae. We have detected both proper motions and ongoing evolution in the jet. These results support a model in which the jet is driven by an accretion disk around an unseen, compact companion. We also find a central, dense equatorial disk-like structure which may enable and/or enhance the formation of the accretion disk. |
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