
science & techESA/Hubble2024 · Gemini constellation
A white dwarf stealing matter from a partner star explodes 650 million light-years away
Hubble has imaged the galaxy LEDA 22057, about 650 million light-years away in Gemini, where a supernova called SN 2024PI appears as a pale blue dot near the core. It was discovered in January 2024 by an automated survey that scans the northern sky every two days. This is a Type Ia supernova, which requires a white dwarf, the dense remnant of a star with less than about eight times the Sun's mass. A white dwarf can explode only if it is in a binary system and pulls material from a companion until it becomes too massive to support itself. The resulting runaway fusion destroys it in a blast visible across many galaxies.
Type Ia supernovae are bright and fairly uniform, which is why astronomers use them to measure distances across the universe. Understanding how they start explains a key tool of modern cosmology.
The Sun will eventually become a white dwarf, about five billion years from now.
