ALMA Observations of the Water Fountain Pre-planetary Nebula IRAS 16342-3814: High-velocity Bipolar Jets and an Expanding Torus
Journal article, 2017

We have mapped 12CO J = 3-2 and other molecular lines from the "water fountain" bipolar pre-planetary nebula (PPN) IRAS 16342-3814 with ?0.?35 resolution using Atacama Large Millimeter/submillimeter Array. We find (i) two very high-speed knotty, jet-like molecular outflows; (ii) a central high-density ( cm-3), expanding torus of diameter 1300 au; and (iii) the circumstellar envelope of the progenitor AGB, generated by a sudden, very large increase in the mass-loss rate to M o yr-1 in the past ?455 years. Strong continuum emission at 0.89 mm from a central source (690 mJy), if due to thermally emitting dust, implies a substantial mass (0.017 M o) of very large (?millimeter-sized) grains. The measured expansion ages of the above structural components imply that the torus (age ?160 years) and the younger high-velocity outflow (age ?110 years) were formed soon after the sharp increase in the AGB mass-loss rate. Assuming a binary model for the jets in IRAS 16342, the high momentum rate for the dominant jet-outflow in IRAS 16342 implies a high minimum accretion rate, ruling out standard Bondi-Hoyle-Lyttleton wind accretion and wind Roche-lobe overflow (RLOF) models with white-dwarf or main-sequence companions. Most likely, enhanced RLOF from the primary or accretion modes operating within common-envelope evolution are needed.

techniques: interferometric

stars: winds

circumstellar matter


stars: AGB and post-AGB

stars: mass-loss


R. Sahai

Jet Propulsion Laboratory, California Institute of Technology

Wouter Vlemmings

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

T. Gledhill

University of Hertfordshire

C. Sánchez Contreras

Centro de Astrobiologia (CAB)

E. Lagadec

Observatoire de la Cote d'Azur

Lars-Åke Nyman

Atacama Large Millimeter-submillimeter Array (ALMA)

European Southern Observatory Santiago

G. Quintana-Lacaci

CSIC - Instituto de Ciencia de Materiales de Madrid (ICMM)

Astrophysical Journal Letters

2041-8205 (ISSN) 2041-8213 (eISSN)

Vol. 835 1 L13

Subject Categories

Fusion, Plasma and Space Physics



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