In the vast mysteries of the Universe lies a curious question about the origins of the metal elements we find on Earth and beyond.
These elements are produced in the heart of stars, but the exact stellar origins have remained elusive.
Focusing on a particular type of supernova, known as Type Ic, scientists are unraveling the cosmic conundrum of these metal-rich star explosions devoid of hydrogen and helium.
Traditionally, it was thought that Type Ic supernovae originated from colossal lone stars burning brightly and briefly.
However, a multinational team led by astronomers Martín Solar and Michał Michałowski has exposed a different narrative.
Their findings suggest these supernovae more frequently emerge from less massive stars working in tandem with a binary companion, reshaping our understanding of these celestial events.
“The more we investigate these massive stars, the more complex they appear,” explained Michałowski.
Mass and metal richness aren’t the only influencers of a star’s fate; companions play a crucial role too.
Type Ic supernovae result when enormous stars, after converting all their hydrogen to heavier elements, reach a critical point in their life cycle.
Their cores collapse under the force of gravity, culminating in the formation of either an ultradense neutron star or a black hole.
The star’s outer layers are then violently expelled, synthesizing even heavier metals in the process.
An intriguing anomaly with these supernovae is their lack of hydrogen or helium in the resulting stellar shell.
Scientists suggest two possible scenarios for this absence: either very massive stars had expelled these elements through powerful stellar winds before the explosion, or a binary companion close enough to siphon these light elements away was involved.
The researchers turned to an innovative approach using data from the PHANGS project, which utilizes the Atacama Large Millimeter Array to analyze molecular gas in star-forming clouds, and tested their hypothesis by peering into the remnants left by Type Ic and Type II supernovae.
They discovered that the molecular hydrogen quantities were akin in both cases, indicating that stars leading to Type Ic supernovae were less massive than previously assumed.
Interestingly, the hydrogen and helium siphoned away by a binary companion can help us trace these stellar explosions’ contributions to the universe’s elemental composition.
For instance, these occurrences aid in producing double the carbon, an essential building block for life.
As scientists extend this ‘astroforensic’ approach to examine more supernova remnants, they aim to explore broader questions.
Michałowski noted that through these investigations, mysteries surrounding the nature of host galaxies, the enigmatic broad emission lines, and how they factor into supernovae characteristics could finally be unraveled.
The revelations of this study, published in Nature Communications, could significantly alter our comprehension of cosmic formation processes and elemental origins.
By examining the progenitor stars of these supernovae, scientists are not just tracing the past lives of stars but reshaping our cosmic narrative.