PSR J0437-4715

The 5.7 millisecond pulsar (PSR) J0437-4715 is one of the most fascinating multi-wavelength objects in the Milky Way:

• It is the closest and brightest millisecond pulsar (MSP), in a binary system with a low mass white dwarf companion and an orbital period of 5.7 days.
• Its companion is the first to be detected at optical wavelengths.
• It is the first MSP to be detected in X-rays.
• It exhibits the greatest long-term rotational stability of any pulsar, with accuracy rivaling that of Earth-based atomic clocks.
• Its timing stability has been used to place one of the strongest limits on the hypothesized background of stochastic gravitational radiation.
• It is the first pulsar for which the full three-dimensional orientation of the binary orbit was determined, enabling a new test of General Relativity.

Optical image of the binary system containing PSR J0437-4715
Credit: Optical image by Andrew S. Fruchter