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A collimated, high-speed outflow from the dying star V Hydrae


Stars with masses in the range 1–8 solar masses (M) live ordinary lives for 109–1010 years, but die extraordinary deaths. First, during their death throes as asymptotic giant branch (AGB) stars they eject, over 104–105 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 transformation1. 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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Figure 1: Optical line emission from a high-velocity, jet-like, knotty outflow in the carbon star V Hya.
Figure 2: A geometrical model of the high-velocity knotty jet and the central continuum source in V Hya.
Figure 3: Observations and geometrical model of a central, dense, equatorial disk in V Hya.
Figure 4: Maps of the CO J = 1–0 emission from V Hya.


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We thank H. Imai for commenting on an earlier version of this paper. We are grateful to NASA for partial financial support, obtained through: the Long Term Space Astrophysics programme for R.S. and M.M.; and grants for R.S. from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under a NASA contract.

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Correspondence to R. Sahai.

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Sahai, R., Morris, M., Knapp, G. et al. A collimated, high-speed outflow from the dying star V Hydrae. Nature 426, 261–264 (2003).

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