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Hayabusa2 Target Too Warm for Ice, Deepening Acceleration Mystery
Japan's Hayabusa2 probe faces a mystery as its next asteroid target is too warm to hold ice, deepening the unexplained acceleration puzzle.
In brief
Japan's Hayabusa2 probe faces a mystery as its next asteroid target is too warm to hold ice, deepening the unexplained acceleration puzzle. Asteroid 1998 KY26 is too warm to retain buried water ice, undermining the dark comet theory for its odd acceleration. Originally reported by BigGo Finance.
Asteroid 1998 KY26
A new study in the journal Icarus finds the asteroid is too warm to retain buried water ice.
“Here, we show that all locations on the surface or in the interior of 1998 KY26 have orbit-averaged temperatures significantly above the sublimation point of volatiles in vacuum”
Temperature Thresholds
Even its coldest regions average at least 212 Kelvin, well above the threshold for ice survival.
Dark Comet Theory
The object was proposed as a dark comet after a 2023 paper found accelerations exceeding the Yarkovsky effect.
Ice Survival Challenge
Water ice needs temperatures below roughly 145 Kelvin to survive for long stretches.
Hayabusa2 Mission Timeline
Hayabusa2 returned samples from Ryugu in 2020 and is due to reach 1998 KY26 in July 2031.
Asteroid Characteristics
1998 KY26 is about 11 meters wide and rotates roughly every five minutes.
Accelerating Mystery
The puzzle dates to 2023 when a study reported non-gravitational accelerations larger than the Yarkovsky effect.
Mission Challenges
1998 KY26 is smaller and spins faster than expected, complicating Hayabusa2's landing attempt.
The essence
Asteroid 1998 KY26 is too warm to retain buried water ice, undermining the dark comet theory for its odd acceleration.
