Issue |
EAS Publications Series
Volume 10, 2003
JENAM 2002, Galactic & Stellar Dynamics
|
|
---|---|---|
Page(s) | 55 - 55 | |
DOI | https://doi.org/10.1051/eas:2003130 | |
Published online | 22 December 2003 |
C. Boily, P. Patsis, S. Portegies Zwart, R. Spurzem and C. Theis (eds)
EAS Publications Series, 10 (2003) 55
The log P -
Relation of Galactic Field RR Lyrae Variables
Sternberg Astronomical Institute, Universitetskii pr. 13, Moscow 119992, Russia
The kinematical parameters of the local field RR Lyrae population
and the zero-point of the log relation for these
variables are inferred by applying the statistical parallax
(maximum-likeli-hood) technique to a sample of 182 RR Lyraes with
known periods, radial-velocities, metallicities, K-band
photometry, and absolute proper motions on the ICRS system.
Hipparcos, Tycho-2, SPM, UCAC, NPM1, and the Four-Million Star
Catalog (Volchkov et al. 1992) were used as
the sources of proper motions; the proper motions of the last two
catalogs are reduced to the Hipparcos (ICRS) system (Dambis &
Rastorguev 2001). The K-band magnitudes were adopted from
the list of Fernley et al. (1998) and
supplemented by the data of the 2MASS Second Incremental Data
Release. The parameters of the velocity distribution are found to
be: (
,
,
km s-1; (
,
,
) km s-1: and (
,
,
) km s-1; (
,
,
) km s-1 for the thick-disk (41 stars) and
halo (141 stars) objects, respectively. The zero-point of the
infrared PL relation of Jones et al. (1992)
(based on the results obtained using the Baade-Wesselink method)
is confirmed: we find
compared to
as
inferred by Jones et al. (1992). A conversion of
the resulting log
relation to V-band luminosities
yields the metallicity-luminosity relation
Fe/H
. Our results imply a solar Galactocentric distance of
kpc and an LMC distance modulus of
(cluster RR Lyraes) or
(field RR Lyraes), thereby favoring
the so-called short distance scale.
© EAS, EDP Sciences, 2003