| |
 |
| Paper: |
The Kinematics and Zero Point of the Log P – <MK> Relation for Galactic Field RR Lyrae Variables via Statistical Parallax |
| Volume: |
310, Variable Stars in the Local Group (IAU Colloquium 193) |
| Page: |
128 |
| Authors: |
Dambis, A.K.; Vozyakova, O.V. |
| Abstract: |
The kinematical parameters of the local field RR Lyrae population and the zero point of the log P − <MK> relation for these variables are inferred by applying the statistical parallax (maxium-likelihood) technique to a sample of 379 RR Lyrae stars with known periods, radial velocities, metallicities, K-band photometry, and absolute proper motions on the ICRS system. Hipparcos, Tocho-2, SPM, UCAC1 and NPM1 were used as the sources of proper motions. The K-band magnitudes were adopted from the 2MASS All-Sky Data Release. The parameters of the velocity distribution are found to be (U0 = −13 ± 9, V0 = −41 ± 7, W0 = −19±4) kms−1, (σU = 66±9, σV = 47±7, σW = 23±5) kms−1 and (U0 = −11±10, V0 = −224±8, W0 = −8±6) kms−1 (σU = 158±9, σV = 95±5, σW = 88±5) kms−1 for the thick-disk (the purest disk sample, 56 stars) and halo (the purest halo sample, 264 stars) objects, respectively. The zero point of the infared PL relation of Jones et al. (1992 − based on the results obtained using the Baade-Wesselink method) is confirmed: we find <MK> = −2.33·log PF −0.89±0.09, which is only 0.m01 brighter than found using the Baade-Wesselink method (Jones et al. 1992). A conversion of the resulting log P− <MK> relation to V-band luminosities yields the metallicity-luminosity relation <MV> = +1.12 + 0.18·[Fe/H] ± 0.10. Our results imply a solar Galactocentric distance of R0 = 7.8±0.4 kpc and an LMC distance modulus of DMLMC = 18.17±0.10 (cluster RR Lyraes) or DMLMC = 18.10±0.10 (field RR Lyraes), thereby favoring the so-called short distance scale. |
|
|
|
|
|
