000001994 001__ 1994
000001994 005__ 20160701171656.0
000001994 0247_ $$2DOI$$a10.1051/0004-6361:20078880
000001994 037__ $$aASTROimport-151
000001994 100__ $$avan de Steene, G. C.
000001994 245__ $$aKinematics and H{2} morphology of the multipolar post-AGB star IRAS 16594-4656
000001994 260__ $$c2008
000001994 520__ $$aContext: The spectrum of IRAS 16594-4656 shows shock-excited H2 emission and collisionally excited emission lines such as [O i], [C i], and [Fe ii].   Aims: The goal is to determine the location of the H2 and [Fe ii] shock emission, to determine the shock velocities, and to constrain the physical properties in the shock.   Methods: High resolution spectra of the H2 1-0 S(1), H2 2-1 S(1), [Fe ii], and Paß emission lines were obtained with the near infrared spectrograph Phoenix on Gemini South. Results: The position-velocity diagrams of H2 1-0 S(1), H2 2-1 S(1), and [Fe ii] are presented. The H2 and [Fe ii] emission is spatially extended. The collisionally excited [O i] and [C i] optical emission lines have a similar double-peaked profile compared to the extracted H2 profile and appear to be produced in the same shock. They all indicate an expansion velocity of ~8 km s-1 and the presence of a neutral, very high-density region with ne about 3 × 106 to 5 × 107 cm-3. However, the [Fe ii] emission is single-peaked. It has a Gaussian FWHM of 30 km s-1 and a total width of 62 km s-1 at 1% of the peak. The Paß profile is even wider with a Gaussian FWHM of 48 km s-1 and a total width of 75 km s-1 at 1% of the peak.   Conclusions: The H2 emission is excited in a slow 5 to 20 km s-1 shock into dense material at the edge of the lobes, caused by the interaction of the AGB ejecta and the post-AGB wind. The 3D representation of the H2 data shows a hollow structure with less H2 emission in the equatorial region. The [Fe ii] emission is not present in the lobes, but originates close to the central star in fast shocks in the post-AGB wind or in a disk. The Paß emission also appears to originate close to the star. Based on observations collected at the Gemini-South with the Phoenix instrument under GS-2003A-Q-41, and VLT under 65.L-0615(A). 
000001994 700__ $$a Ueta, T.
000001994 700__ $$a van Hoof, P. A. M.
000001994 700__ $$a Reyniers, M.
000001994 700__ $$a Ginsburg, A. G.
000001994 773__ $$c775-783$$i3$$pAstronomy and Astrophysics$$v480$$y2008
000001994 85642 $$ahttp://esoads.eso.org/abs/2008A%26A...480..775V
000001994 905__ $$apublished in
000001994 980__ $$aREFERD