Asteroid Phaethon, the origin of the Geminid meteor shower, has been discovered to have a sodium tail rather than one made of dust, challenging previous understandings of the object over the past 14 years. This finding raises questions about the nature of some comets and the source of the Geminid meteors. Phaethon, primarily rocky, behaves like a comet when it nears the Sun, as intense heat can vaporize sodium within its surface, creating a visible tail of sodium. Observations from NASA’s Solar and Heliospheric Observatory (SOHO) and the Stereo spacecraft indicated this sodium tail and confirmed that no detectable dust was emitted.
The brightening of Phaethon when close to the Sun suggests sodium plays a crucial role, akin to known comet behavior. However, the origin of the Geminid meteor shower’s material remains unresolved. Researchers speculate a catastrophic event possibly ejected significant debris from Phaethon thousands of years ago. A planned mission by JAXA, named DESTINY+, set to fly by Phaethon later this decade, aims to provide more insights into this intriguing asteroid’s surface and its role in the meteor shower.
