Her X-1
Her X-1 is one of the best studied X-ray binaries in the sky; this is borne out by the fact that since 2000 there has been more than 30 papers published in refereed journals with ``Her X-1'' in the title. Her X-1 is a binary system, which consists of a neutron star and an A/F secondary star; it has an orbital period of 1.7~day and the spin period of the neutron star is $\sim$1.24~sec. It is one of only a few systems which shows a regular variation in X-rays: the 35 day variation is referred to as the ``beat'' period. We have obtained XMM-Newton data on Her X-1 on more than 15 occasions covering a wide variety of beat phases. This work has been published in Ramsay et al (2002), Jimenez-Garate et al (2002), XMM-Newton Zane et al (2004)

Silvia Zane gave a talk on Her X-1 at the recent meeting in Cefalu, Sicilly. You can get the powerpoint presentation here