  We present an analysis of the spin and orbital properties of the newly
discovered accreting pulsar IGR J17480-2446, located in the globular cluster
Terzan 5. Considering the pulses detected by the Rossi X-ray Timing Explorer at
a period of 90.539645(2) ms, we derive a solution for the 21.27454(8) hr binary
system. The binary mass function is estimated to be 0.021275(5) Msun,
indicating a companion star with a mass larger than 0.4 Msun. The X-ray pulsar
spins up while accreting at a rate of between 1.2 and 1.7E-12 Hz/s, in
agreement with the accretion of disc matter angular momentum given the observed
luminosity.
  We also report the detection of pulsations at the spin period of the source
during a Swift observation performed ~2 d before the beginning of the RXTE
coverage. Assuming that the inner disc radius lies in between the neutron star
radius and the corotation radius while the source shows pulsations, we estimate
the magnetic field of the neutron star to be within ~2E8 G and ~2.4E10 G. From
this estimate, the value of the spin period and of the observed spin-up rate,
we associate this source with the still poorly sampled population of slow,
mildly recycled, accreting pulsars.
