Milky Way Helium Nova Unleashes Cosmic Bullets at 20 Million mph

Using Hubble, plus NASA’s TESS and ground-based telescopes, astronomers confirmed that the Milky Way’s only known helium nova, V445 Puppis, blasts out fast, oxygen-rich clumps—‘bullets’—traveling about 20 million mph. The system comprises a white dwarf accreting helium from a companion helium-star, a rare binary that sheds light on hydrogen-poor stellar explosions and their potential links to Type Ia supernovae; debris clearing over two decades allowed a clearer view of the eruption and hints that another nova could occur.