First Light from Einstein Probe: A Supernova Remnant

On 9 January 2024, the Einstein probe was launched, its mission to study the night sky in X-rays. The first image from the probe that explores the Universe in these energetic wavelengths has just been released. It shows Puppis A, the supernova remnant from a massive star that exploded 4,000 years ago. The image showed the expanding cloud of ejecta from the explosion but now, Einstein will continue to scan the skies for other X-ray events. 

The Chinese and European probe was designed to revolutionise our understanding of the Universe in X-rays. Named after none other than Albert Einstein, it houses cutting edge technology that will enable the observation of black holes, neutron stars and other events and phenomena emitting X-ray radiation. To achieve this it has two science instruments on board; the Wide-field X-ray Telescope (WXT) to give large field views of the sky and the Follow-up X-ray Telescope (FXT) which homes in on objects of interest identified by WXT.

The Einstein probe has three main questions it hopes to address focusing on black holes, gravity waves and supernovae. The recent image just released shows the stunning Puppis A supernova remnant. Supernova are a common process that takes place at the end of a massive star’s life. A star like the Sun is fusing hydrogen in its core into helium. The process is known as thermonuclear fusion and it releases heat, light and an outward pressure known as the thermonuclear force. While a star is stable, the thermonuclear force balances the force of gravity which is trying to collapse the star. 

Massive stars will continue fusing different elements in the core until an iron core remains. It’s not possible to fuse iron so the thermonuclear force ceases allowing gravity to win. the core collapses and the inward rushing material crashes down onto the core and rebounds into a massive explosion known as a supernova. 

Puppis A is one such object that is thought to have exploded 4,000 years ago. It lies about 7,000 light years from us which means the light that the radiation detected by the Einstein probe left about 7,000 years ago. 

In the image released from Einstein, the cloud like structure is all that remains of the star that went supernova. It is possible to see a bright dot at the centre of the cloud, this is the core of the star that remains, a neutron star. The FXT image was accompanied by a spectrum to show the distribution of energy to help understand the elements present. 

Source : Supernova remnant Puppis A imaged by Einstein Probe