Open AccessThe triple‐shell structure and collimated outflows of the planetary nebula NGC 6891
Author(s) -
Guerrero Martín A.,
Miranda Luis F.,
Manchado Arturo,
Vázquez Roberto
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03159.x
Subject(s) - physics , nebula , astrophysics , planetary nebula , shell (structure) , halo , outflow , collimated light , astronomy , stars , galaxy , optics , laser , materials science , meteorology , composite material
Narrow‐band H α and [N ii ] images and high‐dispersion spatially resolved echelle spectroscopy of the planetary nebula NGC 6891 are presented. These observations show a great wealth of structures. The bright central nebula is surrounded by an attached shell and a detached outer halo. Both the inner and intermediate shells can be described as ellipsoids with similar major to minor axial ratios, but different spatial orientations. The kinematical ages of the intermediate shell and halo are 4800 and 28 000 yr, respectively. The intershell time lapse is in good agreement with the evolutionary interpulse time lapse. A highly collimated outflow is observed to protrude from the tips of the major axis of the inner nebula and impact on the outer edge of the intermediate shell. Kinematics and excitation of this outflow provide conclusive evidence that it is deflected during the interaction with the outer edge of the intermediate shell. At the same time, both the kinematics and the morphology of the intermediate shell appear to be affected by this interaction.