(meteorobs) 1972 Draconids [was 2005 Draconids]

[Malcolm J. Currie]

Thank you to all those who addressed my question about the 1972
Draconids.

On Tue, 25 Jan 2005, Jeff Wilson wrote:
> YORP=  ?

This is one of the non-gravitational forces caused by the re-radiation
of heat from a rotating uneven meteoroid (or asteroid), not unlike a
windmill.  YORP is an acronym based upon the initials of those who
investigated it.  Yarkovsky, O'Keefe, Radzievskii, and Paddack.  It's
actually a smaller effect based upon the more widely known and stronger
Yarkovsky effect.  Heat accumulated on the day-side of the meteoroid
means the evening side is warmer than the morning side.  The excess
radiated heat on the evening sides causes a small radiation pressure to
one side of the particle.  Over many orbits this subtle sideways thrust
can amount to a significant deviation from the expected orbit.

Malcolm