Rare helium nova in our galaxy reveals unusual stellar fireworks
Astronomers have confirmed the galaxy’s first helium nova, V445 Puppis, a binary system where a white dwarf siphons material from a helium-star companion; after a dust-enshrouded outburst around 2000, the now-visible ejecta include oxygen-rich “bullets” racing through space at up to 20 million mph. Studying this rare explosion helps illuminate how such novae occur and could shed light on the origins of Type Ia supernovae, which are used as standard candles to gauge cosmic distances.