A possible model of pulsar timing
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Transcript of A possible model of pulsar timing
A possible model A possible model of pulsar timingof pulsar timing
Biping GongBiping Gong
Collaborator Yaping LiCollaborator Yaping Li
KIAA Oct 19, 2012
quasi-periodic feature?
Possible mechanisms
free precession
un-modeled companion exact period
Random processes
quasi-periodic feature? multi-planets ?
Long-term orbital Long-term orbital effects?effects?
geodetic precession of spin axis , geodetic precession of spin axis , BO equationBO equation
Like the effect of free precession, it also predicts a periodic timing delay, without considering the motion of the orbital plane.
BO’s two-body equation BO’s two-body equation
negligible
AK’sAK’s two-body equationtwo-body equation (J=const)(J=const)
( J=const ? )
Just with the basic Just with the basic binary parameters binary parameters like, orbital like, orbital period, mass, and period, mass, and spin parametersspin parameters like, spin angular like, spin angular momentum, we have the following results.momentum, we have the following results.
J=L+S=constJ=L+S=const
PSR B1540-06PSR B1540-06
PSR B1828-11PSR B1828-11
PSR B0919+06PSR B0919+06
PSR B1826-17PSR B1826-17
PSR J1931+2421PSR J1931+2421
Companion star?Companion star?
Spin angular momentumSpin angular momentum , , --
Orbital period , 0.20-0.34 hr
Companion mass , 0.16-0.68 solar mass
Are there binary pulsars with Are there binary pulsars with
orbital period less than 90min ?orbital period less than 90min ?
4U 1626-67 an evidence 4U 1626-67 an evidence of such of such
a scenario?a scenario?
Thanks!