What type of standard candle is used to determine distances to globular clusters?

Question

Quizplus · Accepted Answer

RR Lyrae stars have a known luminosity that makes them useful as standard candles for determining the distances to globular clusters. Cepheid variable stars are often used to determine distances to nearby galaxies, Type I supernovae are used to measure the distances to more distant galaxies, and T Tauri stars are not useful as standard candles as their brightness varies too much.

What Type of Standard Candle Is Used to Determine Distances