Open AccessCircinus X‐1: survivor of a highly asymmetric supernova
Author(s) -
Tauris T. M.,
Fender R. P.,
Van Den Heuvel E. P. J.,
Johnston H. M.,
Wu K.
Publication year - 1999
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.1365-8711.1999.03068.x
Subject(s) - physics , supernova , astrophysics , eccentricity (behavior) , proper motion , star (game theory) , astronomy , supernova remnant , radial velocity , orbital eccentricity , binary number , limiting , stars , mechanical engineering , arithmetic , mathematics , political science , law , engineering
We have analysed the kinematical parameters of Cir X‐1 to constrain the nature of its companion star, the eccentricity of the binary and the pre‐supernova parameter space. We argue that the companion is most likely to be a low‐mass (≲2.0 M ⊙ ) unevolved star and that the eccentricity of the orbit is 0.94±0.04. We have evaluated the dynamical effects of the supernova explosion and we find it must have been asymmetric. On average , we find that a kick of ∼740 km s −1 is needed to account for the recently measured radial velocity of +430 km s −1 (Johnston, Fender & Wu) for this extreme system. The corresponding minimum kick velocity is ∼500 km s −1 . This is the largest kick needed to explain the motion of any observed binary system. If Cir X‐1 is associated with the supernova remnant G321.9‐0.3 then we find a limiting minimum age of this remnant of ∼60 000 yr. Furthermore, we predict that the companion star has lost ∼10 per cent of its mass as a result of stripping and ablation from the impact of the supernova shell shortly after the explosion.