A Tour of Kes 75

Narrator (April Jubett, CXC): Scientists have confirmed the identity of the youngest known pulsar in the Milky Way galaxy using data from NASA's Chandra X-ray Observatory. This result could provide astronomers new information about how some stars end their lives.

After some massive stars run out of nuclear fuel, then collapse and explode as supernovas, they leave behind dense stellar nuggets called "neutron stars". Rapidly rotating and highly magnetized neutron stars produce a lighthouse-like beam of radiation that astronomers detect as pulses as the pulsar's rotation sweeps the beam across the sky.

Since Jocelyn Bell Burnell, Anthony Hewish, and their colleagues first discovered pulsars through their radio emission in the 1960s, over 2,000 of these exotic objects have been identified. However, many mysteries about pulsars remain, including their diverse range of behaviors and the nature of stars that form them.

X-ray data from Chandra are helping address some of those questions. A team of astronomers has confirmed that the supernova remnant Kes 75, located about 19,000 light years from Earth, contains the youngest known pulsar in the Milky Way galaxy.

The rapid rotation and strong magnetic field of the pulsar have generated a wind of energetic matter and antimatter particles that flow away from the pulsar at near the speed of light. This pulsar wind has created a large, magnetized bubble of high-energy particles called a pulsar wind nebula.

Between 2000 and 2016, the Chandra observations reveal that the outer edge of the pulsar wind nebula is expanding at a remarkable 1 million meters per second, or over 2 million miles per hour.

This high speed may be due to the pulsar wind nebula expanding into a relatively low-density environment. Specifically, astronomers suggest it is expanding into a gaseous bubble blown by radioactive nickel formed in the explosion and ejected as the star exploded. This nickel also powered the supernova light, as it decayed into diffuse iron gas that filled the bubble. If so, this gives astronomers insight into the very heart of the exploding star and the elements it created.