what can you tell me about its rotation speed?
one X-ray pulsar that spins at 599 revolutions per second
Millisecond pulsar
Furthermore, one X-ray pulsar that spins at 599 revolutions per second, IGR J00291+5934, is a prime candidate for helping detect such waves in the future 
some globular clusters have three main sequence tracks. this indicates UNANSWERABLE what is this cluster? It is a spherical collection of stars that orbits a galactic core. how is this clusters formed? The formation of globular clusters remains a poorly understood phenomenon and it remains uncertain whether the stars in a globular cluster form in a single generation or are spawned across multiple generations over a period of several hundred million years. what are this composed of? Globular clusters are generally composed of hundreds of thousands of low-metal, old stars. what are its exotic components? Some exotic classes of stars, such as "blue stragglers", "millisecond pulsars", and "low-mass X-ray binaries", are much more common in globular clusters. what is the first one? A blue straggler is a main-sequence star in an open or globular cluster that is more luminous and bluer than stars at the main sequence turnoff point for the cluster. are there any other types of it? "Yellow stragglers" or "red stragglers" what is meant by the second exotic class? It is a pulsar with a rotational period smaller than about 40 milliseconds.
wiki:24448904
Millisecond pulsar [SEP] Pulsar rotational speed limits
However, in early 2007 data from the Rossi X-ray Timing Explorer and INTEGRAL spacecraft discovered a neutron star XTE J1739-285 rotating at 1122 Hz. The result is not statistically significant, with a significance level of only 3 sigma. Therefore, while it is an interesting candidate for further observations, current results are inconclusive. Still, it is believed that gravitational radiation plays a role in slowing the rate of rotation. Furthermore, one X-ray pulsar that spins at 599 revolutions per second, IGR J00291+5934, is a prime candidate for helping detect such waves in the future (most such X-ray pulsars only spin at around 300 rotations per second).