Overview
- Simulations identify Epsilon Canis Majoris (Adhara) and Beta Canis Majoris (Mirzam) as the likely culprits, passing within roughly 30 light-years of the Sun.
- The stars’ ultraviolet output ionized local interstellar gas, with about 20% of hydrogen and 40% of helium stripped of electrons.
- The pair are now around 400 light-years away, and their eventual supernovae are expected to be spectacular but not considered a threat to Earth.
- Researchers note uncertainties in reconstructing the motions of the Sun, stars, and drifting clouds, which make the exact closest approach an estimate.
- Other ultraviolet sources likely helped drive the effect, including radiation from the local hot bubble and several nearby white dwarfs, as the Sun’s current cloud environment may provide shielding relevant to habitability.