Fr.: plume de Mars
A slender, cloudy projection sometimes seen to extend from the surface of → Mars to very high altitudes. Noted and confirmed by amateur astronomers on photos of Mars in March 2012, possibly similar plumes have been found on archived images as far back as 1997. The plumes reach 200 km up, which seems too high for them to be related to wind-blown surface dust. Since one plume lasted for more than 10 days, it seemed too long lasting to be related to → aurora. The origin of this phenomenon is not yet known.
A structure or form that is like a long feather. → polar plume.
From M.E., from O.Fr. plume, from L. pluma "feather, down," from PIE base *pleus- "feather, fleece."
Parr "feather," variant bâl "wing," Mid.Pers. parr "feather, wing," bâl; Av. parəna- "feather," Skt. parnam, cf. O.H.G. farn "fern," PIE pornom "feather."
Fr.: plume polaire
A coronal feature of the Sun, which appears as long, thin streamers that project outward from the Sun's north and south poles