  Re-examination of the COBE DIRBE data reveals the thermal emission of several
comet dust trails. The dust trails of 1P/Halley, 169P/NEAT, and 3200 Phaethon
have not been previously reported. The known trails of 2P/Encke, and
73P/Schwassmann-Wachmann 3 are also seen. The dust trails have 12 and 25 micron
surface brightnesses of <0.1 and <0.15 MJy/sr, respectively, which is <1% of
the zodiacal light intensity. The trails are very difficult to see in any
single daily image of the sky, but are evident as rapidly moving linear
features in movies of the DIRBE data. Some trails are clearest when crossing
through the orbital plane of the parent comet, but others are best seen at high
ecliptic latitudes as the Earth passes over or under the dust trail. All these
comets have known associations with meteor showers. This re-examination also
reveals one additional comet and 13 additional asteroids that had not
previously been recognized in the DIRBE data.
