Answer to Puzzle Contest:

thermometer. The word in question is HARP, and the 3 letters listed can make new words or well known names when added to harp:

HARPY
HARPO
SHARP (or HARPS)

A harp is a musical instrument, and the constellation Lyra is in the shape of a harp. See http://stardate.org/resources/constellations/lyra.html

Winner: fiona rhodes