
The symbiotic star CH Cygni – III. A precessing radio jet
Author(s) -
Crocker M. M.,
Davis R. J.,
Spencer R. E.,
Eyres S. P. S.,
Bode M. F.,
Skopal A.
Publication year - 2002
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.1365-8711.2002.05705.x
Subject(s) - physics , ejecta , astrophysics , precession , symbiotic star , jet (fluid) , astronomy , hubble space telescope , accretion (finance) , accretion disc , stars , supernova , emission spectrum , spectral line , thermodynamics
VLA, MERLIN and Hubble Space Telescope imaging observations of the extended regions of the symbiotic system CH Cygni are analysed. These extensions are evidence of a strong collimation mechanism, probably an accretion disc surrounding the hot component of the system. Over 16 yr (between 1985 and 2001) the general trend is that these jets are seen to precess. Fitting a simple ballistic model of matter ejection to the geometry of the extended regions suggests a period of 6520 ± 150 d , with a precession cone opening angle of 35°± 1° . This period is of the same order as that proposed for the orbital period of the outer giant in the system, suggesting a possible link between the two. Anomalous knots in the emission, not explained by the simple model, are believed to be the result of older, slower moving ejecta, or possibly jet material that has become disrupted through sideways interaction with the surrounding medium.