X-ray pulsars fade as propeller effect sets in | EurekAlert! Science News
https://www.eurekalert.org/pub_releases/2016-11/miop-xpf111716.php
Astrophysicists catch a glimpse of rapidly spinning neutron stars that 'black out'
An international team of astrophysicists including Russian scientists from the Space Research Institute of the Russian Academy of Sciences (RAS),
MIPT, and Pulkovo Observatory of RAS has detected an abrupt decrease of pulsar luminosity following giant outbursts. The phenomenon is associated
with the so-called "propeller effect," which was predicted more than 40 years ago. However, this is the first study to reliably observe the transition
of the two X-ray pulsars 4U 0115+63 and V 0332+53 to the "propeller regime." The results of the observations, the conclusions reached by the researchers,
and the relevant calculations were published in Astronomy & Astrophysics.
The two sources studied, 4U 0115+63 and V 0332+53, belong to a rather special class of transient X-ray pulsars. These stars alternately act as weak X-ray
sources, undergo giant outbursts, and disappear from sight completely. The transitions of pulsars between different states provide valuable information
about their magnetic field and the temperature of the surrounding matter. Such information is indispensable, as the immensely strong magnetic fields and
extremely high temperatures make direct measurements impossible in a laboratory on Earth.