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The central star of the planetary nebula LMC-N66: a massive accreting white dwarf?
Hamann, W. -R.; Peña, M.
The central star of the PN LMC-N66 showed an impressive outburst in 1993 - 1994, returning to its initial conditions about 8 years later. Its spectrum resembles that of a WN4.5 star, being the only confirmed central star of planetary nebulae showing such a spectral type. Recent analysis for the central star parameters, performed by Hamann et al. (…
Proper Motions of Stellar Jets as Observed with HST: The Movies
Hartigan, P. M.
The brightest stellar jets are close enough that they exhibit definite proper motions over a period of a few years when observed with the Hubble Space Telescope (HST). Results for the HH 1, HH 34, HH 47, and HH 111 jets, based on H alpha and [S II] HST images separated by about five years, are now available. A new interpolation algorithm for movin…
Multipolar Bubbles, Point-Symmetry, and Jets in Dying Stars
Sahai, R.; Morris, M. R.
The imaging of young planetary and pre-planetary nebulae (YPNe and PPNe) with unprecedented high angular resolution and dynamic range using the Hubble Space Telescope (HST), has shown that most of these objects are highly aspherical, with complex multipolar morphologies. The complexity, organization and symmetry of the morphological structures has…
Eta Carinae: Bullet Streams and Colliding Wind Shocks
Currie, D. G.
Eta Carinae, the most massive and most luminous star in our Galaxy, erupted in 1842 with an energy rivaling a supernova. It ejected approximately two solar masses of material to form an extended bipolar nebula (the homunculus), a variety of massive ``bullets'' (NN and NS knots and the South Bar) and the ``spikes'' (long narrow strings of bullets).…
Bipolar and Multipolar Jets in Protoplanetary and Planetary Nebulae
Sahai, R.
One of the most exciting challenges facing theories of post-main sequence evolution today is to understand how Asymptotic Giant Branch (AGB) stars and their round circumstellar envelopes (CSEs) transform themselves into planetary nebulae (PNe) with their dazzling variety of aspherical morphologies. The most succesful model for shaping PNe--the ``g…
Bubbles, Bow-Shocks, and Bullets over Broad-lines: Three Ionized Outflows Resolved with HST
Veilleux, S.; Ferruit, P.; Cecil, G.
HST images and spectra of high-velocity outflows from three AGN: (1) Show 5 arcsec -long bow shock/Mach disk complexes at the ends of the active radio jet in NGC 4258. We argue that the jet has precessed to its current orientation seen at VLBI-scales. (2) Fully resolve [O III]5007Å and H beta line profiles in the NLR of NGC 1068, and show compact …
New Observations of the High-Velocity Outflows of the Proto-Planetary Nebula Hen 3-1475
García-Lario, P.; Riera, A.; Manchado, A. +2 more
The proto-planetary nebula Hen 3-1475 shows a remarkable highly collimated optical jet with a S-shaped string of shock-excited knots. Moreover, extremely high velocities have been observed in the innermost regions of its jet. We present a detailed analysis of the kinematic structure, and the excitation conditions in the shock-excited knots based o…
The LBV Phase of the Planetary Nebula LMC-N66
Peña, M.
Recent observations of the [WN] central star of the planetary nebula LMC-N66, combined with previous data show that the star has been slowly fading, after its violent LBV-type outburst occurred in 1994. The present stellar brightness ( m[V] ~ 18.1 mag) and the probable mass loss rate are similar to the values observed in 1990. Nebular data from lo…
An Ionized Microjet from the Orion Nebula Proplyd LV 2
Henney, W. J.; Meaburn, J.; Garrington, S. T.
We present results of multi-wavelength observations of the Orion nebula proplyd LV 2 (M42 167-317), concentrating on our analysis of the microjet that emerges from the proplyd's ionization front. The microjet is one-sided at its base but faint, symmetrical jet filaments are seen on both sides at arcsecond scales. The physical characteristics of th…
The Structure of the Planetary Nebula IC 2149: A Jet or an Edge-On Ring?
López, J. A.; Torrelles, J. M.; Miranda, L. F. +4 more
A set of optical and radio observations of the peculiar planetary nebula (PN) IC 2149 is presented. A bow-shock-like feature towards the NE edge is first detected with the VLA-A, and is also confirmed with HST archive images. Optical spectroscopy leads to apparently contradictory results, leaving this object as a unique case among the planetary ne…