12 March 2024
Record-breaking image of a dead star’s scattered remains
This billowing mass of dust filaments and gas tendrils stretching across 100 light years of space is the Vela supernova remnant – the scattered ashes of a star that exploded about 11,000 years ago. The image was acquired by the Dark Energy Camera (DECam), mounted on the Victor M. Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile. DECam was originally designed to conduct a survey of distant galaxies to measure the strength of dark energy as it accelerates the universe’s expansion and draws those galaxies away from us. On completion of that survey, however, DECam has been used in a more general fashion. It is one of the most powerful wide-field instruments ever built, and this image of the Vela supernova remnant is proof of its capabilities. It’s the largest image ever released by the camera at 1.3 gigapixels in size.
The image has to be large to capture all that detail across such a large swath of sky. The Vela supernova remnant is a nebula that is about 100 light years across. Because it’s about 800 light years away from us, this means the Vela supernova remnant spans an area on the celestial sphere 20 times larger than the angular diameter of the full Moon. The Vela supernova remnant itself is of crucial astronomical importance. It gives us a good look at the late stages of the development of such a remnant and offers insight into how material blown out by the supernova gradually disperses into the interstellar medium, which is the thin mist of gas that fills the space between stars.
The shock wave from the ancient stellar explosion that formed the Vela supernova remnant is still expanding into space, where it is colliding with the interstellar medium and compressing it, creating the delicate filaments we can see in the image. Absorption lines from elements like calcium, carbon, copper, germanium, krypton, magnesium, nickel, oxygen and silicon – many of them ionised and doubly ionised – have been detected in the supernova debris as well. These are heavy elements forged either by fusion processes within the star before it exploded or by the ferocious energies unleashed by the explosion itself.
9 March 2024
Webb hones in on a star-forming region
Spectacular new images from the James Webb Space Telescope reveal the stunning and
