TABLE  hipparcos_new_reduction

Hipparcos New Reduction: The Astrometric Catalogue

A new reduction of the astrometric data as produced by the Hipparcos mission
has been published, claiming accuracies for nearly all stars brighter than
magnitude Hp=8 to be better, by up to a factor 4, than in the original catalogue.
The new Hipparcos astrometric catalogue is checked for the quality of the data
and the consistency of the formal errors as well as the possible presence of
error correlations. The differences with the earlier publication are explained.
The internal errors are followed through the reduction process, and the external
errors are investigated on the basis of a comparison with radio observations of
a small selection of stars, and the distribution of negative parallaxes. Error
correlation levels are investigated and the reduction by more than a factor 10
as obtained in the new catalogue is explained. The formal errors on the parallaxes
for the new catalogue are confirmed. The presence of a small amount of additional
noise, though unlikely, cannot be ruled out. The new reduction of the Hipparcos
astrometric data provides an improvement by a factor 2.2 in the total weight
compared to the catalogue published in 1997, and provides much improved data for
a wide range of studies on stellar luminosities and local galactic kinematics.

Required constraints:
  • Primary key is (hip)

NameTypeLengthUnitDescriptionDefault ValueUnified Content Descriptor
hipint4 Hipparcos identifier meta.main;meta.id
icint4 Entry in one of the supplementary catalogues meta.id.cross
rafloat8degreesRight Ascension in the ICRS at epoch 1991.25 meta.main;pos.eq.ra
decfloat8degreesDeclination in the ICRS at epoch 1991.25 meta.main;pos.eq.dec
ra_radfloat8radiansRight Ascension in the ICRS at epoch 1991.25 pos.eq.ra
de_radfloat8radiansDeclination in the ICRS at epoch 1991.25 pos.eq.dec
plxfloat8milliarcsecondsParallax pos.parallax
pm_rafloat8milliarcseconds/yearProper motion in Right Ascension pos.eq.ra;pos.pm
pm_defloat8milliarcseconds/yearProper motion in Declination pos.eq.dec;pos.pm
e_ra_radfloat8milliarcsecFormal error on ra_rad pos.eq.ra;stat.error
e_de_radfloat8milliarcsecFormal error on de_rad pos.eq.dec;stat.error
e_plxfloat8milliarcsecFormal error on parallax pos.parallax;stat.error
e_pm_rafloat8milliarcsec/yearFormal error on pm_ra pos.eq.ra;pos.pm;stat.error
e_pm_defloat8milliarcsec/yearFormal error on pm_de pos.eq.dec;pos.pm;stat.error
f1int4 Percentage rejected data arith.ratio;stat.value
f2float8 Goodness of fit stat.fit.goodness
ncint4 Number of components meta.number
ntrint4 Number of field transits used meta.id;obs.field
u3float8 Upper-triangular weight matric element 3 stat.weight
u4float8 Upper-triangular weight matric element 4 stat.weight
u5float8 Upper-triangular weight matric element 5 stat.weight
u6float8 Upper-triangular weight matric element 6 stat.weight
u7float8 Upper-triangular weight matric element 7 stat.weight
u8float8 Upper-triangular weight matric element 8 stat.weight
u9float8 Upper-triangular weight matric element 9 stat.weight
snint4 Solution type in the New Reduction meta.id;stat.fit
soint4 Solution type in the old reduction meta.id;stat.fit
varfloat8 Cosmic dispersion added (stochastc solution) stat.fit.residual
u1float8 Upper-triangular weight matric element 1 stat.weight
u2float8 Upper-triangular weight matric element 2 stat.weight
u10float8 Upper-triangular weight matric element 10 stat.weight
u11float8 Upper-triangular weight matric element 11 stat.weight
u12float8 Upper-triangular weight matric element 12 stat.weight
u13float8 Upper-triangular weight matric element 13 stat.weight
u14float8 Upper-triangular weight matric element 14 stat.weight
u15float8 Upper-triangular weight matric element 15 stat.weight
hp_magfloat8magHipparcos magnitude em.opt;phot.mag
b_vfloat8magB-V colour index phot.color;em.opt.B;em.opt.V
v_ifloat8magV-I colour index phot.color;em.opt.V;em.opt.I
e_hp_magfloat8magError on mean Hipparcos magnitude em.opt.V;phot.mag;stat.error
e_b_vfloat8magFormal error on B-V colour index em.opt;phot.colour;stat.error
s_hpfloat8magScatter in Hipparcos magnitudes stat.error;phot.mag;em.opt
vaint4 Reference to variability annex meta.note
cxfloat8 unit vector of spherical co-ordinates pos.distance;pos.cartesian.x
cyfloat8 unit vector of spherical co-ordinates pos.distance;pos.cartesian.y
czfloat8 unit vector of spherical co-ordinates pos.distance;pos.cartesian.z
htmIDbigint8 Hierarchical Triangular Mesh (HTM) index, 20 deep, for equatorial co-ordinates pos.eq
Total length344