Asteroid 1998 KY26 Defies Orbital Expectations
Most space rocks follow predictable trajectories dictated by gravity and solar radiation pressure. Asteroid 1998 KY26 accelerates in a manner that defies standard expectations for how celestial bodies behave, ScienceAlert reported.
Measuring just 11 meters across, the small asteroid rotates once every 5.35 minutes. Its trajectory exhibits unusual acceleration perpendicular to the plane of its orbit, drawing intense scrutiny from planetary scientists trying to decode its unusual path.
Temperature Modeling Rules Out Cometary Ice
One leading hypothesis suggested that 1998 KY26 operates as a dark cometary body. These objects possess invisible cometary activity, spewing out gases without generating the luminous tails typical of traditional comets.
To test this hypothesis, aerospace engineers Korbin Hansen and Masatoshi Hirabayashi from the Georgia Institute of Technology modeled temperatures across the surface and deep interior of 1998 KY26. Their findings appear in the journal Icarus.
For buried water ice to survive over long spans, ambient temperatures must stay below roughly 145 Kelvin. However, the researchers discovered that even the coldest regions of the asteroid maintain an average temperature of at least 212 Kelvin throughout its orbit.
Our temperature model results indicate that the water outgassing rate on 1998 KY26 would be too high to maintain buried ice, refining the understanding of the asteroid’s composition,
Hansen and Hirabayashi write.
Solar Radiation Pressure Explains the Object Acceleration
At these elevated temperatures, any water ice making up one percent of the asteroid’s mass would dissipate in just over two millennia. If that ice drove the observed acceleration, it would vanish completely in a mere 62 years.
With the dark comet explanation faltering, scientists point to solar radiation pressure as a plausible driver for the object’s acceleration. An earlier paper traces the object to a potential asteroid belt origin.
Definitive answers may arrive soon. The Japanese space agency’s Hayabusa2 spacecraft is journeying toward 1998 KY26, with a scheduled rendezvous slated for July 2031.
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