pint.derived_quantities.pbdot
- pint.derived_quantities.pbdot(mp: Unit('solMass'), mc: Unit('solMass'), pb: Unit('d'), e: Unit(dimensionless))[source]
Post-Keplerian orbital decay pbdot, assuming general relativity.
pbdot (\(\dot P_B\)) is the change in the binary orbital period due to emission of gravitational waves. Can handle scalar or array inputs.
- Parameters:
mp (astropy.units.Quantity) – pulsar mass
mc (astropy.units.Quantity) – companion mass
pb (astropy.units.Quantity) – Binary orbital period
e (astropy.units.Quantity or float) – orbital eccentricity
- Returns:
pbdot – (dimensionless)
- Return type:
- Raises:
astropy.units.UnitsError – If the input data are not appropriate quantities
TypeError – If the input data are not quantities
Notes
Calculates
\[\dot P_b = -\frac{192\pi}{5}T_{\odot}^{5/3} \left(\frac{P_b}{2\pi}\right)^{-5/3} f(e)\frac{m_p m_c}{(m_p+m_c)^{1/3}}\]with
\[f(e)=\frac{1+(73/24)e^2+(37/96)e^4}{(1-e^2)^{7/2}}\]and \(T_\odot = GM_\odot c^{-3}\).
More details in Timing Models. Also see [5].