Sindarin adjective Car- from Quenya Carne : Red.
A single but as many of the named stars in the second setting of stars a planet, Mars.
Carnil is positively identified as Mars by JRR Tolkien in a draft year 1951 for his revision of The Silmarillion, chapter; Of the Coming of the Elves. It might be worth to mention that in the thoughts of JRR Tolkien the planets were newer distinguished from the real stars.
Valian Years of the Trees.
V.Y.t.1000-1050. Carnil was set in the sky in Varda`s second making of stars. From the vats of Telperion she took silver dew and made new and brighter stars against the coming of the Firstborn.
Related links.: Encyc.: Carnil., Stars, the prophecy and the creation.