RR Lyrae

RR Lyrae

AAVSO light curve of RR Lyrae. Different colors reflect different bandpasses.
Observation data
Epoch J2000      Equinox J2000
Constellation Lyra
Right ascension 19h 25m 27.9129s
Declination +42° 47′ 03.696″
Apparent magnitude (V) 7.13
Characteristics
Spectral type F5
Variable type RR Lyr
Astrometry
Radial velocity (Rv) -72.4 km/s
Proper motion (μ) RA: -109.59 mas/yr
Dec.: -195.54 mas/yr
Parallax (π) 3.79 ± 0.19 mas
Distance 860 ± 40 ly
(260 ± 10 pc)
Absolute magnitude (MV) 0.61±0.11[1]
Details
Mass ? M
Radius ? R
Luminosity ? L
Temperature ? K
Metallicity ?
Rotation ?
Age ? years
Other designations
V* RR Lyr, 2MASS J19252793+4247040, TD1 24704, AG+42° 1698, G 125-7, NLTT 47799, TYC 3142-494-1, AN 34.1901, GSC 03142-00494, NSVS 5543125, USNO-B1.0 1327-00425262, ASCC 425414, HD 182989, PLX 4550, USNO 886, BD+42° 3338, HIC 95497, PPM 58291, uvby98 100182989 V, GAT 791, HIP 95497, SAO 48421, GC 26836, LSPM J1925+4247, GCRV 11873, LTT 15677, SV* HV 180.
Database references
SIMBAD data

RR Lyrae is a variable star in the Lyra constellation. It is the prototype of the RR Lyrae variable class of stars. 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, nearly 49 times solar luminosity.

References

  1. ^ Benedict, George (July 2008). "An Astrometric Calibration of Population II Distance Indicators". HST Proposal ID #11789. Cycle 17: 11789. Bibcode 2008hst..prop11789B. 

See also