pint.derived_quantities.pulsar_age
- pint.derived_quantities.pulsar_age(f: Unit("Hz"), fdot: Unit("Hz / s"), n=3, fo=<Quantity 1.e+99 Hz>)[source]
Compute pulsar characteristic age
Return the age of a pulsar given the spin frequency and frequency derivative. By default, the characteristic age is returned (assuming a braking index n =3 and an initial spin frequency \(f_0 \gg f\)). But n and fo can be set.
- Parameters:
f (astropy.units.Quantity) – pulsar frequency
fdot (astropy.units.Quantity) – frequency derivative \(\dot f\)
n (int, optional) – braking index (default = 3)
fo (astropy.units.Quantity, optional) – initial frequency \(f_0\)
- Returns:
age – pulsar age in
u.yr- Return type:
- Raises:
astropy.units.UnitsError – If the input data are not appropriate quantities
TypeError – If the input data are not quantities
Notes
Calculates
\[\tau = \frac{f}{(n-1)\dot f}\left(1-\left(\frac{f}{f_0}\right)^{n-1}\right)\]