Open AccessBlunting the spike: the cataclysmic variable minimum period
Author(s) -
King A. R.,
Schenker K.,
Hameury J. M.
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.1365-8711.2002.05659.x
Subject(s) - physics , cataclysmic variable star , astrophysics , spike (software development) , magnetic field , variable (mathematics) , range (aeronautics) , astronomy , stars , white dwarf , mathematical analysis , materials science , mathematics , management , quantum mechanics , economics , composite material
The standard picture of cataclysmic variable (CV) secular evolution predicts a spike in the CV distribution near the observed short‐period cut‐off P 0 ≃ 78 min , which is not observed. We show that an intrinsic spread in minimum (‘bounce’) periods P b resulting from a genuine difference in some parameter controlling the evolution can remove the spike without smearing the sharpness of the cut‐off. The most probable second parameter is different admixtures of magnetic stellar wind braking (at up to 5 times the GR rate) in a small tail of systems, perhaps implying that the donor magnetic field strength at formation is a second parameter specifying CV evolution. We suggest that magnetic braking resumes below the gap with a wide range, being well below the GR rate in most CVs, but significantly above it in a small tail.