Title: PSR J1311-3430: A Heavyweight Neutron Star with a Flyweight Helium Companion Authors: Roger W. Romani, Alexei V. Filippenko, Jeffery M. Silverman, S. Bradley Cenko, Jochen Greiner, Arne Rau, Jonathan Elliott, Holger J. Pletsch
We have obtained initial spectroscopic observations and additional photometry of the newly discovered Pb=94min gamma-ray black-widow pulsar PSR J1311-3430. The Keck spectra show a He-dominated, nearly H-free photosphere and a large radial-velocity amplitude of 609.5±7.5km/s. Simultaneous seven-colour GROND photometry further probes the heating of this companion, and shows the presence of a flaring infrared excess. We have modelled the quiescent light curve, constraining the orbital inclination and masses. Simple heated light-curve fits give M_NS=2.7 solar masses, but show systematic light-curve differences. Adding extra components allows a larger mass range to be fit, but all viable solutions have M_NS>2.1 solar masses. If confirmed, such a large M_NS substantially constrains the equation of state of matter at supernuclear densities.
The newly found pulsar, known as PSR J13113430, has been vaporizing material off its companion, speeding up the pulsar's spin and gradually moving the stars closer together. The pair now fly around each other in 93 minutes -- faster than any other pulsar binary found to date. PSR J13113430 is a type of pulsar known as a "black widow," because like the black widow spider, which kills its smaller male partner after mating, the pulsar may eventually completely destroy its partner. Read more
Max Planck scientists discover record-breaking millisecond pulsar with new analysis method
Pulsars are the compact remnants from explosions of massive stars. Some of them spin around their own axis hundreds of times per second, emitting beams of radiation into space. Until now, they could only be found through their pulsed radio emissions. Now, scientists at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) in Hanover assisted by the Max Planck Institute for Radio Astronomy have discovered a millisecond pulsar solely via its pulsed gamma radiation. A new data analysis method developed by the AEI was crucial for the success. The pulsar is accompanied by an unusual sub-stellar partner, which it is vaporizing, hence the name "black widow". Read more