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What does Ammonia trace in Egg Nebula Pao-Jan Chiu Pao-Jan Chiu With Jeremy Lim 2003 8.27
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Outline Optical Structure of the Egg Nebula 12 CO Molecular Outflows Structure of NH 3 (1,1) Observations with VLA Results and Discussion Summary
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CRL2688 - Egg Nebula Proto-Planetary nebula (PPN) Distance ~ 1 kpc Optical features bipolar lobes twin searchlight beams quasi-spherical AGB wind shocked molecular hydrogen “dust lane”
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Multiple Outflows in Egg nebula 12 CO trace multiple outflows. Shocked molecular hydrogen traces lobes of polar outflow, tips of “equatorial” outflows. Arrow – axis of 12 CO outflows contour – 12 CO Arrow – axis of 12 CO outflows contour – 12 CO color – optical image + shocked H 2 color – optical image + shocked H 2
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NH 3 (1,1) in Egg nebula Equatorial disk or central toru? Nguyen-Q-Rieu, A. Winnberg, V. Bujarrabal,1986 VLA D array, beamsize 4”.3 × 3”.4 Redial velocites from -63.5 to -23.9 km/s NH 3 (1,1) aligned with the dust lane Kinematics suggest expansion: Expanding Disk Spur to north? Bipolar lobes NH3(1,1) -75~ 5km/s -63.5~-23.9km/s
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Observations observer VLA D-array objective NH 3 (3,3) in Egg frequency 23.874 GHz wavelength 1.3 cm bandwidth 12.5 MHz velocity range -110.4 ~ 46.4 km/s bandwidth pre channel 195.3 Hz ( 2.454 km/s ) beam size 3.19”×2.51”
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Results and Discussion At higher angular resolution, structure of NH 3 (3,3) does not resemble disk Beamsize 4”.3 × 3”.4 Beamsize 3”.19 × 2”.51 NH 3 (1,1) Comparison of NH 3 (3,3) andNH 3 (1,1) NH3(3,3)
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Compare with optical lobes and shocked H 2 NH 3 (3,3) traces higher density (~10 5 -10 6 ) and higher temperature (~120K) than 12 CO (2-1) The four NH 3 (3,3) peaks are at/close to tips of 12 CO outflows. NH 3 (3,3) traces shocked molecular gas behind the shock front (traced by shocked molecular hydrogen) color – optical image + shocked H2 color – optical image + shocked H2 contour – NH 3 (3,3) contour – 12 CO contour – NH 3 (3,3) contour – 12 CO
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outflows 12 CO Shock region cooling region Shocked H 2 H 2 NH 3 (3,3) 12 CO cooling region Shocked H 2 H 2 NH 3 (3,3) Shocked H 2 H 2
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Compare with optical lobes and shocked H 2 NH 3 (3,3) traces higher density (~10 5 -10 6 ) and higher temperature (~120K) than 12 CO (2-1) The four NH 3 (3,3) peaks are at/close to tips of 12 CO outflows. NH 3 (3,3) traces shocked molecular gas behind the shock front (traced by shocked molecular hydrogen) color – optical image + shocked H2 color – optical image + shocked H2 contour – NH 3 (3,3) contour – 12 CO contour – NH 3 (3,3) contour – 12 CO
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Velocity distribution in NH 3 North and east NH3(3,3) peaks are blueshifted South and west NH3(3,3) peaks are redshifted Kinematics of NH 3 (3,3) similar to 12 CO outflow NH 3 (3,3) NH 3 (3,3) Contour - 12 CO Color arrow - 12 CO outflows
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Summary Observed NH3(3,3) in Egg Nebula with VLA NH 3 (3,3) trace the higher density and temperature molecule gas Observed NH3(3,3) in Egg Nebula with VLA NH 3 (3,3) trace the higher density and temperature molecule gas NH 3 (3,3) not consistent with expanding disk NH 3 (3,3) not consistent with expanding disk NH 3 (3,3) located at/close to tips of 12 CO outflows and behind the shocked molecular hydrogen gas NH 3 (3,3) located at/close to tips of 12 CO outflows and behind the shocked molecular hydrogen gas Kinematics of NH3(3,3) similar to 12 CO outflows Kinematics of NH3(3,3) similar to 12 CO outflows NH3(3,3) traces shocked molecular gas behind the shock front (traced by shocked molecular hydrogen) NH3(3,3) traces shocked molecular gas behind the shock front (traced by shocked molecular hydrogen) Does the “equatorial” outflows lie in the same plane; i.e., disk that is aligned with the dust lane Does the “equatorial” outflows lie in the same plane; i.e., disk that is aligned with the dust lane
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Orientation of the Multiple “Equatorial” Outflows Two models: Model 1. Oriented in different directions, with no common plane Model 2. “Equatorial” Outflows lie in the plane of a “disk” aligned with the dust lane
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Orientation of the Multiple “Equatorial” Outflows Two models: Model 1. Oriented in different directions, with no common plane Model 2. “Equatorial” Outflows lie in the plane of a “disk” aligned with the dust lane Model 2 requires the “disk” to be (rapidly) rotating
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Thank you !!
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