Distance indicator · Primary rung
RR Lyrae Stars
Old, pulsating horizontal-branch stars with a well-defined luminosity, especially tight when measured in the infrared. Abundant in globular clusters and the haloes of galaxies, they are a standard candle for old stellar populations and, like the Cepheids, are calibrated directly by parallax.
Highlights
- ›The standard candle of old stellar populations
Methods, objects & facilities
Knowledge connections
- Associated withStandard Candles
- Associated withParallax
- Associated withThe Cosmic Distance Ladder
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.