Description of Part III of the FK6 Catalogue
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Field 1:
FK6 number
The FK6 number of the star is identical with its FK5 number (for the FK5
stars) or its FK4Sup number (for the RSup stars).
The numbering system in the fundamental catalogues is historically grown
and not explained here.
Field 2:
HIP number
Number of the star in the HIPPARCOS Catalogue (ESA 1997).
This numbering follows closely ordering by right ascension alpha
for the epoch J1991.25 (not J2000.0 !).
Field 3:
Flag for the subsample of FK6(III) stars
BX = star from the bright extension of the FK5
FX = star from the faint extension of the FK5
RS = star from the RSup (Schwan et al. 1993).
Field 4:
Name
Some star names are given for an easier identification of the object by a
reader of the catalogue.
Fields 5-14:
The Fields 5-14 contain the FK6 results in the single-star
(SI) mode.
Field 5:
alpha 2000 (SI mode)
The right ascension alpha of the star at epoch and equinox J2000.0 in
the ICRS/HIPPARCOS system for the SI mode of the FK6. alpha is given in the
printed catalogue in the conventional sexagesimal
units of hours, minutes of time, and seconds of time. The
machine-readable version of the FK6 gives alpha also in degrees and decimal
fractions of degrees. Below we use the notation alpha_* = alpha*cos(delta),
as it is done in the HIPPARCOS Catalogue.
Field 6:
delta 2000 (SI mode)
The declination delta of the star at epoch and equinox J2000.0 in the
ICRS/HIPPARCOS system for the SI mode of the FK6. delta is given in the
printed catalogue in the conventional sexagesimal
units of degrees, minutes of arc, and seconds of arc.
The machine-readable version of the FK6 gives delta also in
degrees and decimal fractions of degrees.
Field 7:
mu_alpha_* 2000 (SI mode)
The proper-motion component mu_alpha of the star in alpha_* at
epoch and equinox J2000.0 in
the ICRS/HIPPARCOS system for the SI mode of the FK6. Instead of the
conventional way of presenting mu_alpha, the catalogue gives
mu_alpha_* = mu_alpha*cos(delta) in milliarcseconds (mas)/year.
Field 8:
mu_delta 2000 (SI mode)
The proper-motion component mu_delta of the star in delta at epoch and
equinox J2000.0 in the ICRS/HIPPARCOS
system for the SI mode of the FK6. Unit: mas/year.
Field 9:
T_alpha (SI mode)
Central epoch T_alpha in alpha of the star in the SI mode. The catalogue
gives T_alpha - 1900 in order to save printing space. Unit: years.
Field 10:
epsilon_alpha (SI mode)
Mean error epsilon_alpha_* of alpha_* of the star at the
central epoch T_alpha (given in Field 9) in the SI mode. Unit: mas.
Field 11:
epsilon_mu_alpha (SI mode)
Mean error epsilon_mu_alpha_* of mu_alpha_* of the star in
the SI mode. Unit: mas/year.
Field 12:
T_delta (SI mode)
Central epoch T_delta in delta of the star in the SI mode. The catalogue
gives T_delta - 1900 in order to save printing space. Unit: years.
Field 13:
epsilon_delta (SI mode)
Mean error epsilon_delta of delta of the star at the
central epoch T_delta (given in Field 12) in the SI mode. Unit: mas.
Field 14:
epsilon_mu_delta (SI mode)
Mean error epsilon_mu_delta of mu_delta of the star in
the SI mode. Unit: mas/year.
Field 15:
p_res
'Resulting' parallax p_res of the star (see Section 9). This is either
the HIPPARCOS parallax or a photometric/spectroscopic parallax. Unit: mas.
Field 16:
epsilon_p_res
Mean error epsilon_p_res of p_res. Unit: mas.
Field 17:
K_p_res
Flag for the source of p_res:
H = HIPPARCOS Catalogue (ESA 1997)
P = Newly determined photometric/spectroscopic parallax
Field 18:
v_rad
Radial velocity v_rad of the star, used in calculating
the foreshortening effect. Unit : km/s.
Field 19:
m_V
Apparent visual magnitude m_V of the star, taken from the HIPPARCOS Catalogue.
Field 20:
K_m
Flag for the variability of the brightness of the star, taken from the
HIPPARCOS Catalogue (HIP Field H6):
blank = star not variable
1 = star variable at the level of < 0.06 mag
2 = star variable at the level of 0.06 - 0.6 mag
3 = star variable at the level of > 0.6 mag
Field 21:
K_bin
Flag for the double-star nature of the object:
K_bin = d_1 d_2 = 10*d_1 + d_2
First digit d_1:
The first digit d_1 describes the information on the double-star nature based
on the proper-motion differences Delta_mu. The method and the meaning of
the corresponding test parameters F are explained in Wielen et al. (1999a).
1 = all values of F (F_{FH}, F_{0H}, F_{0(GC)H}, F_{0F}, F_{TH}) are below 2.49
2 = at least one value of F (F_{FH}, F_{0H}, F_{0(GC)H}, F_{0F}, F_{TH}) is larger than 3.44
3 = all other (intermediate) cases
Second digit d_2:
The second digit d_2 describes the information on the
double-star nature based on various other methods. If
the data indicate various kinds of binarity, the
'astrometrically most disturbing' effect is given.
1 = single star indicated
2 = the star is a member of a visual binary (gravitationally bound system),
or the object is resolved by speckle interferometry
3 = the object is suspected to be a visual binary (mainly due to HIP)
4 = the star has at least one optical companion with a separation of rho < 60"
5 = the star has at least one optical companion, but all
companions have a separation of rho >= 60"
6 = astrometric binary (mainly the non-standard solutions O, G, V, X of HIP)
7 = spectroscopic binary with a known orbit, or the star is an eclipsing binary
8 = the radial velocity of the star is variable (indicating a spectroscopic binary),
or the object shows a composite spectrum (indicating a double star)
9 = the radial velocity of the star may be variable
(possible indication for a spectroscopic binary),
or the object may show a composite spectrum
(possibly indicating a double star),
or other weak indications of binarity,
or the star has a (suspected) planetary companion
Field 22:
K_Delta_mu
Flag for the double-star nature of the object based on differences between
various proper motions (Wielen et al. 1999a):
1 = single-star candidate
2 = Delta_mu binary
blank = uncertain (between 1 and 2),
or the binary nature which is indicated by other data does
not allow to classify the object as a single-star candidate
Field 23:
K_ae
Flag for 'astrometrically excellent stars' (see Section 3):
3 = astrometrically excellent star with rank ***
2 = astrometrically excellent star with rank **
1 = astrometrically excellent star with rank *
blank = star not classified as astrometrically excellent
Fields 24-33:
General remarks:
In contrast to Part I of the FK6, the printed version of Part III
contains for the other modes of the FK6 the proper motions and their mean
errors only. The positions, central epochs, and parallaxes derived for these
modes are given in the machine-readable version of the FK6(III). The field
'FK5' is an abbreviation; it should be read in detail as 'FK5 or RSup', since
for the RSup stars, the corresponding data had to be taken from the RSup
Catalogue.
In order to save printing space, we give for the other modes of the FK6, i.e.
the long-term prediction (LTP) and the short-term prediction (STP), and for HIP
(HIPPARCOS Catalogue) and FK5 (or RSup), not the full quantities, but only
their differences, Delta = other mode - SI mode,
with respect to the single-star
(SI) mode of the FK6. These differences have to be added to the results of the
SI mode of the FK6 (Fields 7 and 8) in order to obtain the results of the other
modes. The data given
for the FK5 (or RSup) and for mu_0 are given in the ICRS/HIPPARCOS system.
Since the quantities for the SI
mode and all the differences Delta refer to the epoch
and equinox J2000.0 in the ICRS/HIPPARCOS
system, this is then also the case for the full results of the
other modes.
The differences Delta are given for numerical and printing convenience only.
Therefore, the mean errors given in the FK6 Catalogue are not the errors of
these differences, but those of the full quantities in the other modes. The
mean errors given for the FK5 (or RSup) and for mu_0 include the mean errors
of the systematic differences between the FK5 system and the HIPPARCOS system.
Fields 24-28:
Delta_mu_alpha_* (LTP, STP, HIP, FK5, mu_0)
Difference Delta_mu_alpha_* between mu_alpha_* in the other
solutions (LTP, STP, HIP, FK5, mu_0)
and mu_alpha_* in the SI mode at epoch and equinox
J2000.0. Unit: mas/year.
Fields 29-33:
Delta_mu_delta (LTP, STP, HIP, FK5, mu_0)
Difference Delta_mu_delta between mu_delta in the other solutions (LTP,
STP, HIP, FK5, mu_0) and mu_delta in the SI mode at epoch and equinox
J2000.0. Unit: mas/year.
Fields 34-38:
epsilon_mu_alpha_* (LTP, STP, HIP, FK5, mu_0)
Mean error epsilon_mu_alpha_* of mu_alpha_* of the star in
the solutions LTP, STP, HIP, FK5, mu_0. Unit: mas/year.
Fields 39-43:
epsilon_mu_delta (LTP, STP, HIP, FK5, mu_0)
Mean error epsilon_mu_delta of mu_delta of the star in
the solutions LTP, STP, HIP, FK5, mu_0. Unit: mas/year.
Field 44:
F_{FH}
F parameter based on the difference Delta_mu_{FH} = mu_F - mu_H between
the proper motions given by the FK5 (or RSup) and by HIPPARCOS.
Field 45:
F_{0H}
F parameter based on the difference Delta_mu_{0H} = mu_0 - mu_H between
the proper motion mu_0 (based on the stellar positions in the FK5 (or RSup)
and in the HIPPARCOS Catalogue) and the proper motion mu_H given by HIPPARCOS.
Field 46:
F_{0(GC)H}
F parameter based on the difference Delta_mu_{0(GC)H} = mu_{0(GC)} - mu_H between
the proper motion mu_0 (based on the stellar positions in the GC (Boss et al. 1937) and
in the HIPPARCOS Catalogue) and the proper motion mu_H given by HIPPARCOS.
Field 47:
F_{0F}
F parameter based on the difference Delta_mu_{0F} = mu_0 - mu_F between
the proper motion mu_0 (based on the stellar positions in the FK5 (or RSup) and
in the HIPPARCOS Catalogue) and the proper motion mu_F given by the FK5 (or RSup).
Field 48:
F_{TH}
F parameter based on the difference Delta_mu_{TH} = mu_T - mu_H between
the proper motion mu_T given in TYCHO2 Catalogue (Hoeg et al. 2000) and the
proper motion mu_H given by HIPPARCOS.
Field 49:
Indicator of a tabular note and number of an individual note
The presence of a tabular note in the printed version of the FK6(III) is
indicated by a 't' in Field 49. The tabular notes are explained on pages
293-294 and are listed on pages 295-306. The individual notes are numbered
consecutively from 3001) to 3024) and are listed on pages 307-308.
Updated: 30 October 2000