The cosmic explosion that marks the end of a star’s life has long been a topic of fascination for astronomers. For the first time, scientists have captured visual evidence of a star meeting its end by detonating twice. The remains of supernova SNR 0509-67.5, studied with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), show patterns that confirm its star suffered a pair of explosive blasts.

The explosions of white dwarfs play a crucial role in astronomy. Much of our knowledge of how the Universe expands rests on Type Ia supernovae, and they are also the primary source of iron on our planet, including the iron in our blood. However, despite their importance, the exact mechanism triggering these explosions remains unsolved.

All models that explain Type Ia supernovae begin with a white dwarf in a pair of stars. If it orbits close enough to the other star in this pair, the dwarf can steal material from its partner. In the most established theory behind Type Ia supernovae, the white dwarf accumulates matter from its companion until it reaches a critical mass, at which point it undergoes a single explosion.

However, recent studies have hinted that at least some Type Ia supernovae could be better explained by a double explosion triggered before the star reached this critical mass. This alternative model suggests that the white dwarf forms a blanket of stolen helium around itself, which can become unstable and ignite. This first explosion generates a shockwave that travels around the white dwarf and inwards, triggering a second detonation in the core of the star — ultimately creating the supernova.

Until now, there had been no clear, visual evidence of a white dwarf undergoing a double detonation. Recently, astronomers have predicted that this process would create a distinctive pattern or fingerprint in the supernova’s still-glowing remains, visible long after the initial explosion. Research suggests that remnants of such a supernova would contain two separate shells of calcium.

Astronomers have now found this fingerprint in a supernova’s remains. Ivo Seitenzahl, who led the observations and was at Germany’s Heidelberg Institute for Theoretical Studies when the study was conducted, says these results show “a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the ‘double-detonation’ mechanism does indeed occur in nature.”

The team were able to detect these calcium layers (in blue in the image) in the supernova remnant SNR 0509-67.5 by observing it with the Multi Unit Spectroscopic Explorer (MUSE) on ESO’s VLT. This provides strong evidence that a Type Ia supernova can occur before its parent white dwarf reaches a critical mass.

Type Ia supernovae are key to our understanding of the Universe. They behave in very consistent ways, and their brightness allows them to be seen from vast distances. By studying these cosmic events, scientists gain insights into the life cycles of stars and the evolution of the cosmos itself.

The discovery of a double-detonation mechanism in Type Ia supernovae has significant implications for our understanding of the Universe. It suggests that these explosions can occur at different stages of a star’s life, potentially leading to new observations and a deeper understanding of the cosmic web.

As scientists continue to study the remnants of supernova SNR 0509-67.5, they may uncover more secrets about the double-detonation mechanism and its role in shaping the Universe. The findings of this research have far-reaching implications for our understanding of the cosmos and the life cycles of stars.

The James Webb Space Telescope (JWST) has revolutionized our understanding of galaxy formation by providing unprecedented views of distant galaxies. A recent study published in the Monthly Notices of the Royal Astronomical Society has used JWST images to unlock a 10-billion-year mystery of how galaxies shape themselves.

Researchers have long known that many galaxies, including our own Milky Way, consist of two distinct parts: a thin disk and a thick disk. The thin disk contains younger, metal-rich stars, while the thick disk is composed of older, metal-poor stars. However, until now, these components had only been identified in nearby galaxies.

The study used 111 JWST images of distant edge-on galaxies to examine their vertical disk structures. This allowed researchers to observe how galaxies have built their disks over cosmic history. The findings revealed a consistent trend: in the earlier universe, more galaxies appear to have had a single thick disk, while in later epochs, more galaxies showed a two-layered structure with an additional thin disk component.

This suggests that galaxies first formed a thick disk, followed by the formation of a thin disk within it. In more massive galaxies, this thin disk appears to have formed earlier. The study estimated the thin disk formation time for Milky Way-sized galaxies to be around 8 billion years ago, aligning with formation timelines for the Milky Way itself.

The research team examined not only the stellar structure but also the motion of gas, direct ingredients of stars obtained from the Atacama Large Millimeter/submillimeter Array (ALMA) and ground-based surveys in the literature. These observations supported a coherent formation scenario: galaxies first formed a thick disk, followed by the formation of a thin disk within it.

The study hopes to bridge studies of nearby galaxies with far away ones and refine our understanding of disk formation. The findings provide valuable insights into galaxy evolution and answer one of the biggest questions in astronomy: was our galaxy’s formation typical or unique?

The universe has long been a mystery waiting to be unraveled. Recent discoveries have shed new light on one of its most fascinating phenomena: planet formation around young stars. Research led by Ayumu Shoshi and his team at Kyushu University and the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) reveals that signs of planet formation may appear earlier than expected, providing a better understanding of this complex process.

The journey to form planets begins with protostars – stars still in the making. These nascent stars are surrounded by disks composed of low-temperature molecular gas and dust, known as protoplanetary disks. It’s within these disks that planets take shape. However, observing these early stages of planet formation directly is a challenge due to their distance from Earth.

The research team utilized improved data processing techniques to reanalyze archive data from the ALMA radio telescope. Their focus was on the Ophiuchus star-forming region, located 460 light-years away in the direction of the constellation Ophiuchus. The team produced high-resolution images of 78 disks, with more than half achieving a resolution over three times better than previous images.

The new images show striking patterns – ring or spiral shapes – in 27 of the disks, with 15 identified for the first time in this study. Combining these findings with previous work on another star-forming region, the team discovered that characteristic disk substructures emerge in disks larger than 30 astronomical units (au) around stars just a few hundred thousand years after they were born.

This groundbreaking research suggests that planets may begin to form at an earlier stage than previously believed, when the disk still possesses abundant gas and dust. In essence, planets grow together with their very young host stars, opening doors to new insights into the origins of our solar system and potentially habitable planets like Earth.