The Explosive Letter S: How a Dying Star Draws Loops in Space express
In a gas cloud left after a star exploded (called a supernova remnant), astronomers noticed a giant glowing letter S. It was drawn by two jets of superheated material ejected during the cataclysm. These jets didn't just shoot straight out — they slowly spun like a top, which bent their path into curves. The process is similar to a garden sprinkler that rotates and draws zigzags with water, except the scale is billions of times larger and instead of water, it's plasma.
But what twisted these ejections? The most unexpected answer is cosmic cannibalism. One hypothesis suggests that a neutron star (the ultra-dense core of the dead star) tore apart a neighboring white dwarf, and as it devoured its matter, it spat out spinning jets. Another possibility: the explosion originated in a layer rich in helium and oxygen, and itself possessed rotation. Similar S-shaped figures are found in other supernova remnants — it seems such a curly flourish is left behind after many stellar deaths.
Original abstract
as written by the authors arXiv:2603.21307
We identify an S-shaped morphological feature in the enigmatic supernova remnant (SNR) 3C 397, which we attribute to the shaping by a precessing pair of jets during the explosion. We identify an S-shaped, faint region composed of two bubbles, located to the north and south of the center, between two X-ray-bright sides. We attribute the S-shape to a pair of precessing jets that were part of the explosion process. The identification of a main jet axis in SNR 3C 397 increases its similarity to the enigmatic SNR W49B. We discuss two possible scenarios for SNR 3C 397 and W49B. (1) The thermonuclear common-envelope-jet supernova scenario, which was suggested before for W49B, where a neutron star destroys a white dwarf and accretes part of the white dwarf's material via an accretion disk that undergoes a thermonuclear outburst and launches the jets. (2) The collapse-induced thermonuclear jet-driven explosion, which is a core-collapse supernova driven by jets, as in the majority of, or even all, core-collapse supernovae, and in addition, there is a thermonuclear outburst of a rare helium-oxygen mixed layer in the core, which is triggered by the core collapse. Our study emphasizes the primary role of jets even in the enigmatic SNR 3C 397.
The speed of matter in such jets reaches 99% of the speed of light — nearly 300,000 km/s, but instead of a direct punch, they curve into elegant letters.