Spin down age

The spin-down age ( English spin down age is) an estimate of the age of a rotating neutron star with the following assumptions:

• The neutron star rotates in a vacuum .
• The magnetic flux density has been constant since the neutron star was formed.
• The magnetic field is a simple dipole field .
• The magnetic poles are on the axis of rotation.

So the age can be estimated with the following formula:

${\displaystyle t=0{,}5\cdot P\cdot {\dot {P}}}$,

where is the rotation period and the dimensionless change in the rotation period. Although the assumptions made do not apply in reality, the spin-down age does not overestimate the actual age by more than a factor of two if an independent age indicator is available, such as B. a historical record of the supernova eruption. The spin-down age can be applied to pulsars , X-ray dim isolated neutron stars , soft gamma repeaters , unusual X-ray pulsars , central compact objects in supernova remnants and rotating radio transients . ${\displaystyle P}$ ${\displaystyle {\dot {P}}}$

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• Fulvio Melia: High-Energy Astrophysics . Princeton University Press, Princeton 2009, ISBN 978-0-691-14029-2 .
• AGL Lyne, F. Graham-Smith: Pulsars . Johann Ambrosius Barth Verlag, Leipzig 1993, ISBN 3-335-00336-5 .