AAS 197, January 2001
Session 6. Planetary Nebulae: Young and Old
Display, Monday, January 8, 2001, 9:30am-7:00pm, Exhibit Hall

[Previous] | [Session 6] | [Next]


[6.05] The Structure of NGC 7027: Outflows, Holes, and the Early Development of Planetary Nebulae

P.J. Huggins (NYU), P. Cox (IAS), J.-P. Maillard (IAP), E. Habart (IAS), C. Morisset (LAS), R. Bachiller (OAN), T. Forveille (Obs. de Grenoble)

We present high resolution spectro-imaging of the young planetary nebula NGC 7027 at 2 \mum using BEAR with the 3.6 m CFHT. The observations reveal the detailed structure and kinematics of the ionized gas and the surrounding neutral envelope in velocity-resolved (\Delta v = 8 km s-1) images of Br\gamma, He I, He II, and the v=1-0 S(1) line of H2. The ionized gas is seen to form a roughly ellipsoidal shell, expanding at a velocity of ~ 20 km s-1 along the line of sight. The H2 emission forms a bi-conical structure around the ionized nebula, and is shown to arise in a geometrically thin shell (<1'') which precisely traces the inner surface of the extended molecular envelope seen in CO, as predicted by photo-dissociation region models. A dominant feature of the H2 shell is the presence of multiple, point-symmetric lobes, which we attribute to the effects of bipolar outflows from the central star. Along one axis, we resolve bipolar holes in the H2 emission and detect high velocity Br\gamma emission where the outflows have pierced the inner surface of the neutral envelope. The presence of these outflow-envelope interactions in this well studied archetype, as well as a number of other cases, underscores their importance in the early shaping history of planetary nebulae.


[Previous] | [Session 6] | [Next]