Astronomers find the youngest known pulsar of the Milky Way

Using data from NASA's Chandra X-ray observatory, a team of astronomers has successfully confirmed the most recent known pulsar of the Milky Way. The mission has been studying the rest of the supernova for more than 15 years and has gathered valuable information on its rapid expansion, physical properties and environment. This new discovery could provide key information on the death of stars.

Pulsing through the space

When a massive star collapses on itself and explodes into a supernova, it leaves behind a tiny, incredibly dense neutron star. This highly magnetized, rapidly rotating star emits a beam of light radiation that is sometimes visible in the Earth's field of vision. When this happens, we can see the beam "pulse" in passing.

More than 2,000 such pulsars have been detected since their discovery in 1967, but many aspects of these pulsars, such as the stars from which they were born and their evolution, remain a mystery.

But fortunately, Chandra helps to shed light on their particular properties. A team of astronomers from North Carolina State University recently used Chandra data from 2000, 2006, 2009, and 2016 to study Kes 75, a pulsar located just 19 000 light-years from Earth. Their results also appear in The astrophysical journal.

They discovered that, when the highly magnetized neutron star rotates rapidly, Kes 75 generates a pulsar nebula, a bubble of particles that are wind-fed matter and antimatter. flowing from the star almost at the speed of light. Shown in blue on the photo above, this nebula is growing at a rate of 3.2 million kilometers per hour. Based on this rate of expansion, the team was able to trace its birth to barely 500 terrestrial years, making it the youngest known pulsar of the Milky Way. (In this case, the term "birth" refers to the time when the light from the supernova blast would have been spotted from Earth after 19,000 years of travel.)

Supernova dissection

Since it is such a rapid expansion, astronomers believe that the pulsar lives in an easily penetrable and low density environment. They suggest that this lower density bubble is mainly made up of radioactive nickel formed and ejected during the explosion of the supernova. This nickel could also be responsible for the brightness of the supernova, as it releases visible light when it disintegrates into ferrous gas. If this is true, astronomers would have an idea of ​​the elements that made up the host star before it exploded.

Despite its rapid expansion, the total brightness of the pulsar nebula has decreased by about 10% since 2000, with some areas decreasing by about 30%. And thanks to years of detailed observations, researchers can begin to understand the strange actions and evolution of Kes 75 and better understand the curious nature of pulsars.