Spaceflight 🚀Computing the orbital dynamics of a #NEA is a difficult problem. The leading source of orbital uncertainty for #Apophis is the #Yarkovsky effect https://www.nature.com/articles/s43247-021-00337-x
Non-zero Yarkovsky acceleration for near-Earth asteroid (99942) Apophis - Communications Earth & Environment
The Yarkovsky acceleration acting on near-Earth asteroid (99942) Apophis is large enough to require consideration when evaluating the object’s course and future close passes of Earth, according to an analysis of astrometry data collected including the 2021 flyby.
AkaSci 🛰️The Yarkovsky effect affects the orbit of small rotating bodies.
An object's day side heats up due to the sun and gradually radiates away the heat as it rotates. The surface is hottest and the radiation highest not at noon but around 2-3 p.m. This creates a net force in the 8-9 a.m. direction as shown below.
With prograde rotation, the force speeds up the body and expands its orbit. For retrograde rotation (like that of Bennu), the orbit shrinks.
https://skyandtelescope.org/astronomy-news/apophis-pays-a-visit-this-week/
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#Bennu #Yarkovsky
