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Berkeley-Illinois-Maryland Assoc. (BIMA) Array
CO J=1-0 Survey
M. Meixner (STScI)
Collaborators: Fong, Justtanont,Sutton, Welch, Zalucha
Background/motivationObservationsModelsSummary
Conclusions
• Observed features: expanding shells, protrusions, collimated outflows, rotation
• Kinematic trichotomy: -simple expansion with protrusions
found in elliptical (SOLE) PPN -expansion + collimated outflows found in bipolar (DUPLEX) PPN -expansion + rotation (new class)
• Mass loss histories
Motivations for CO J=1-0
• Best tracer of molecular gas mass
• AGB mass loss is predominantly molecular
• Kinematics in proto-planetary nebulae (0.5 km/s)
• Toughest molecule w.r.t. photodissociation => probes outer regions
CO
Observations
• Millimeter interferometry with the BIMA array
• Combined with single dish maps from the NRAO 12 m
• Full synthesis maps provide– Spectral resolution 1 km/s, coverage 128 km/s– 0.5" to 200" scale sizes
Three kinematic signatures
I. Simple expansion: IRC+10216 (Fong), IRAS 22272+5435, HD179821, HD 161796, HD 56126, IRAS 21282+5050
II. Expansion + collimated outflows: AFGL 2688, NGC 7027, AFGL 618
III. Expansion + rotation: Mira, 89 Her, Red Rectangle (Doering)
Expansion + collimated outflows
• Velocity of collimated outflow is faster than the expansion velocity of the envelope (AFGL 2688 and NGC 7027)
• Collimated outflows or bullets?
Expansion + rotation
• Rotation? Or low velocity bipolar outflow?
• Expansion velocity of the envelope is greater than the rotation/bipolar velocity (Mira, 89 Her)
• In either case, they are kinematically distinct from expansion + collimated outflow
HD 56126: Models & Observ.
Parameter Value
D 2.4 kpc
Rin 3.6×1016 cm
Rout 2.5×1017 cm
RSW 1.3×1017 cm
Vexp 11 km s-1
CO/H2 1.1×10-3
dMAGB/dt 5×10-6 MO yr-1
dMSW/dt 3×10-5 MO yr-1
Mgas/Mdust 800
Conclusions
• Observed features: expanding shells, protrusions, collimated outflows, rotation
• Kinematic trichotomy: -simple expansion with protrusions
found in elliptical (SOLE) PPN -expansion + collimated outflows found in bipolar (DUPLEX) PPN -expansion + rotation (new class)
• Mass loss histories
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