Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-04-22
Astron.J.130:853,2005
Astronomy and Astrophysics
Astrophysics
comments: 16 pages, 5 Figs, Fig 1 in color, accepted by AJ (August 2005)
Scientific paper
10.1086/431253
We present high-dispersion long-slit IR spectra of the double-shell bipolar planetary nebula M 2-9 in the emission lines [Fe II] 16435 and H2 v=1--0 S(1) 21218. H2 spectra reveal for the first time the kinematic structure of the outer shell in M 2-9. Kinematics of the inner shell, traced by [Fe II], resemble those of optical lines like [N II]. [Fe II] and H2 shells have expansion speeds roughly proportional to distance from the star (``Hubble'' flows) and share the same dynamical age of 1200--2000 yr, depending on the distance to M 2-9. Thus, the inner ionized lobes and outer molecular lobes, as well as the molecular torus and ``outer loops'' measured by other observers, were all formed around the same time. Consequently, their nested structure likely arises from an excitation gradient rather than independent ejections. H2 and [Fe II] emission is distributed more uniformly than [N II], and IR lines are not dominated by the moving ionization pattern like visual-wavelength lines. We suggest that this is because IR lines of [Fe II] and H2 are excited by relatively isotropic far-UV radiation (Balmer continuum), whereas optical lines respond to a directed rotating beam of Lyman continuum. Finally, we highlight intriguing similarities between M 2-9 and the Homunculus of eta Carinae, despite the different central engines powering the two nebulae.
Balick Bruce
Gehrz Robert D.
Smith Nathan
No associations
LandOfFree
Kinematic Structure of H2 and [Fe II] in the Bipolar Planetary Nebula M 2-9 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Kinematic Structure of H2 and [Fe II] in the Bipolar Planetary Nebula M 2-9, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Kinematic Structure of H2 and [Fe II] in the Bipolar Planetary Nebula M 2-9 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-612231