TY - JOUR
T1 - ALMA Observations of the Water Fountain Pre-Planetary Nebula IRAS 16342-3814: High-velocity bipolar jets and an Expanding Torus
AU - Sahai, Raghvendra
AU - Vlemmings, W.H.T.
AU - Gledhill, Timothy
AU - Sanchez Contreras, Carmen
AU - Lagadec, Eric
AU - Nyman, L.A.
AU - Quintana-Lacaci, G.
N1 - R. Sahai, W.H.T. Vlemmings, T. Gledhill, C. Sanchez Contreras, E. Lagadec, L-A Nyman, and G. Quintana-Lacaci, ‘ALMA Observations of the Water Fountain Pre-planetary Nebula IRAS 16342-3814: High-velocity Bipolar Jets and an Expanding Torus’, The Astrophysical Journal Letters, Vol 835: L13 (6 pp), published 20 January 2017.
The version of record is available online via doi: 10.3847/2041-8213/835/1/L13
© 2017. The American Astronomical Society. All rights reserved.
PY - 2017/1/20
Y1 - 2017/1/20
N2 - 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 (>few x106 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 >3.5 x10-4 Ms 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 Ms) 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.
AB - 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 (>few x106 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 >3.5 x10-4 Ms 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 Ms) 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.
KW - circumstellar matter
KW - stars: AGB and post-AGB
KW - stars: mass-loss
KW - stars: winds, outflows
KW - techniques: interferometric
U2 - 10.3847/2041-8213/835/1/l13
DO - 10.3847/2041-8213/835/1/l13
M3 - Article
SN - 0004-637X
VL - 835
JO - The Astrophysical Journal
JF - The Astrophysical Journal
M1 - L13
ER -