The Absolute Magnitude of Rr Lyrae
نویسندگان
چکیده
We derive the absolute magnitude of RR Lyrae stars by two independent maximum-likelihood estimations , using Hipparcos proper motion and par-allax data, respectively. By applying the statistical parallax method to 99 Halo RR Lyrae stars, we obtain the mean absolute magnitude < M V > = 0:69 0:10 at ={1.58. Independently of this method, we furthermore derive the M V { Fe/H] relation from Hippparcos parallaxes for 125 RR Lyrae stars including negative ones by the method of Ratnatunga & Casertano. We obtain M V =0.91(0.88)+0.21(0.63))Fe/H]. For 99 Halo RR Lyrae stars, < M V > = 0:65 0:33 is also derived .
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