RR LYRAE

'RR Lyrae' is a variable star in the Lyra constellation. It is the prototype of the RR Lyrae variables star class. It has a period of about 13 hours, and oscillates between apparent magnitudes 7 and 8. Its variable nature was discovered by the Scottish astronomer Williamina Fleming at Harvard Observatory in 1901. As RR Lyrae variables are important standard candles, knowing the precise distance of this star is necessary to determine its luminosity, and hence that of other stars in its class.
Its distance long uncertain, the Hubble Space Telescope's Fine Guidance Sensor was used in 2002 to determine the distance of RR Lyrae within ~5%: 262 parsecs, or 854 light-years. If accurate, this gives RR Lyrae an absolute magnitude of 0.61, roughly 49 times solar luminosity.

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References

★ Burnham's Celestial Handbook, Volume 2, , Robert, Jr., Burnham, Dover Publications, , ISBN 0-486-23568-8

★ Benedict, et al., "Astrometry with the Hubble Space Telescope: a parallax of the fundamental distance calibrator RR Lyrae"

See also

★ RR Lyrae variable