czsky/en/star/RR_Lyrae.md

name	constellation	created_by	created_date	updated_by	updated_date
RR Lyrae	Lyr	8mag	2022-01-21 17:00:00	skybber	2022-02-10 16:52:11.152132

this star, lying on the border with the Cygnus, invisible to the naked eye, is a representative of an important class of variable stars whose brightness varies in a short period. They are old stars found mainly around the Galactic centre and in globular clusters, the oldest formations in the galaxy. RR Lyra pulses periodically, like Delta Cephei, but its period is less than a day - 0.567 days. In that time - 13 hours and 36 minutes - the apparent brightness varies from 7mag to 8.1mag. The cycle can therefore be observed (from some areas) in virtually one night. At its maximum it is white, at its minimum it takes on a yellowish tint.