Open AccessThe ejecta from the luminous blue variable star P Cygni
Author(s) -
Meaburn J.,
O'connor J. A.,
López J. A.,
Bryce M.,
Redman M. P.,
NoriegaCrespo A.
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.1365-8711.2000.03763.x
Subject(s) - physics , astrophysics , ejecta , astronomy , shell (structure) , collimated light , asymptotic giant branch , roche lobe , radial velocity , variable star , lobe , binary star , stars , optics , supernova , medicine , laser , materials science , composite material , anatomy
Further optical observations have been made with the Manchester Occulting Mask Imager and Manchester Echelle Spectrometer of the inner and outer shells of P Cygni, and of the 7‐arcmin long giant lobe projecting from this luminous blue variable star. An image in the light of the fluorescently excited [Ni ii ] 7378‐Å line has revealed the knottiness of the inner shell. Well defined ‘velocity ellipses’ for the position/velocity arrays across the outer shell indicate that its expansion velocity is 160 km s −1 which is somewhat lower than the previously reported value. The kinematical behaviour of the giant lobe, both in the vicinity of P Cygni, and further away, emphasizes its strange nature, although close association with P Cygni is again suggested by these new observations. One possibility is that this lobe is a ‘trail’ of collimated ejected material. The observations are compared with a 60‐μm IRAS high‐resolution map of the region. A variety of possible explanations of the observed phenomena are explored, e.g. radio knots in the outer stellar wind either coalesce or expand to become the [Ni ii ]7378‐Å emitting knots in the inner shell; that a mass‐loaded wind overunning slower moving clumps explains the kinematics of the inner shell; that the one‐sided giant lobe could be a ‘trail’ of ejected material from P Cygni funnelled through the outer shell.