pint.derived_quantities.pbdot

pint.derived_quantities.pbdot(mp: Quantity, mc: Quantity, pb: Quantity, e: float | Quantity) → Quantity[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:

astropy.units.Quantity

Raises:

astropy.units.UnitsError – If the input data are not appropriate quantities
TypeError – If the input data are not quantities

Notes

Calculates

\[\begin{split}\\dot P_b = -\\frac{192\\pi}{5}T_{\\odot}^{5/3} \\left(\\frac{P_b}{2\\pi}\\right)^{-5/3} f(e)\\frac{m_p m_c}{(m_p+m_c)^{1/3}}\end{split}\]

with

\[\begin{split}f(e)=\\frac{1+(73/24)e^2+(37/96)e^4}{(1-e^2)^{7/2}}\end{split}\]

and \(T_\\odot = GM_\\odot c^{-3}\).

More details in Timing Models. Also see [5].