The C5 to C7 indicates various classifications using the newer Morgan-Keenan system where the numeric index corresponds better to the temperature of the star.

The second numeric index, 3 or 4 for UU Aurigae indicates the strength of the Swan bands in the spectrum, on a scale of 1 to 5.

[11] Using the more modern revised Morgan-Keenan scheme, a spectral type of C-N5- C2 6- has been published, with the C-N5 indicating an N-type carbon star with a temperature index of 5-, and a Swan band strength of 6- on a scale of 1 to 8.

[12] UU Aurigae is classified as a semiregular variable of type SRb, indicating it is a giant star with poorly defined variations.

[16] UU Aurigae also has a bow shock 0.14 parsec wide, created by its motion through the interstellar medium.