[12] The variable nature of RR Lyrae was discovered by the Scottish astronomer Williamina Fleming at Harvard Observatory in 1901.

This type of low-mass star has consumed the hydrogen at its core, evolved away from the main sequence, and passed through the red giant stage.

Energy is now being produced by the thermonuclear fusion of helium at its core, and the star has entered an evolutionary stage called the horizontal branch (HB).

[12] RR Lyrae shows just such a regular pattern of pulsation, which is causing its apparent magnitude to vary between 7.06 and 8.12 over a short cycle lasting 0.567 days (13 hours, 36 minutes).

[15] As with other RR Lyrae-type variables, RR Lyrae itself has a low abundance of elements other than hydrogen and helium – what astronomers term its metallicity: It belongs to the Population II category of stars that formed during the early period of the Universe when there was a lower abundance of metals in star-forming regions.