Open AccessCluster AgeS Experiment (CASE): RR Lyrae stars from the globular cluster ω Centauri as standard candles
Author(s) -
Olech A.,
Kaluzny J.,
Thompson I. B.,
SchwarzenbergCzerny A.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06930.x
Subject(s) - physics , globular cluster , distance modulus , astrophysics , rr lyrae variable , light curve , photometry (optics) , cosmic distance ladder , large magellanic cloud , metallicity , stars , astronomy , cepheid variable , absolute magnitude , apparent magnitude , galaxy , redshift
New photometry of RRab and RRc stars in ω Centauri is used to calibrate their absolute magnitudes M V as a function of (a) metallicity and (b) the Fourier parameters of light curves in the V band. The zero point of both calibrations relies on the distance modulus to the cluster derived earlier by the Cluster AgeS Experiment (CASE) project based on observations of the detached eclipsing binary OGLE GC17. For RRab variables, we obtained a relation of M V = (0.26 ± 0.08)[ Fe/H ] + (0.91 ± 0.13) . A dereddened distance modulus to the Large Magellanic Cloud (LMC) based on that formula is μ 0 = 18.56 ± 0.14 mag . The second calibration of M V , which is based on Fourier coefficients of decomposed light curves, results in the LMC distance of μ 0 = 18.51 ± 0.07 mag .