1250 I/250 The Tycho Reference Catalogue E Hog A Kuzmin U Bastian C Fabricius K Kuimov L Lindegren V V Makarov S Roeser Astron. Astrophys. 335L, 65 ??? ??? 1998 1998A&A...335L..65H I/220 : The HST Guide Star Catalog (Lasker+ 1992) I/239 : The Hipparcos and Tycho Catalogues (ESA 1997) I/246 : The ACT Reference Catalog (Urban+ 1997) Positional data Proper motions Astrographic zones Historical catalog Photographic catalog Surveys Cross identifications astrometry reference catalogs proper motions Astrographic Catalogue Tycho Catalogue The Tycho Reference Catalogue (TRC) contains high-quality positions and proper motions for 990182 stars of the Tycho Catalogue. The proper motions were derived from Tycho positions and Astrographic Catalogue positions reduced to the Hipparcos system. The median accuracy of the TRC position components is 40 mas at J1991.25. The median accuracy of the proper motion is about 2.5 mas/yr. Systematic errors are less than about 1.0 mas(/yr). The quality of the proper motions in TRC is assessed by comparison with the Hipparcos and Tycho Catalogues. Comparison with the recent ACT Catalogue which is based on an independent reduction of the same observations as used for constructing the TRC is reported.

Hipparcos

TYCID1 TYCID1 from TYC number=1 The TYCID1 is the GSC region number, the TYCID2 is the running number within the region, the TYCID3 is a component identifier (normally 1). Some non-GSC running numbers were constructed for TYC. The recommended star designation contains a hyphen between the TYCID numbers, e.g. TYC 1-13-1. --- TYCID2 TYCID2 from TYC number=1 The TYCID1 is the GSC region number, the TYCID2 is the running number within the region, the TYCID3 is a component identifier (normally 1). Some non-GSC running numbers were constructed for TYC. The recommended star designation contains a hyphen between the TYCID numbers, e.g. TYC 1-13-1. --- TYCID3 TYCID3 from TYC number=1 The TYCID1 is the GSC region number, the TYCID2 is the running number within the region, the TYCID3 is a component identifier (normally 1). Some non-GSC running numbers were constructed for TYC. The recommended star designation contains a hyphen between the TYCID numbers, e.g. TYC 1-13-1. --- RAdeg Right Ascension, ICRS, at epoch J2000 deg DEdeg Declination, ICRS, at epoch J2000 deg pmRA prop. mot. in RA * cos(dec) mas/a pmDE proper motion in Dec mas/a epRA mean epoch of RA number=2 The mean epochs are given in Julian years. a epDE mean epoch of Dec number=2 The mean epochs are given in Julian years. a e_RAdeg s.e. RA * cos(dec), at mean epoch number=3 The standard errors given are for the mean epoch. They are in the range 1.0-117.1. The standard errors at some epoch, t, are obtained as e_RA(t)* = sqrt((f*e_RA*)^2^ + ((e_pmRA*)*(t-epRA))^2^ ) and e_DE(t) = sqrt((f*e_DE)^2^ + (e_pmDE*(t-epRA))^2^ ) A factor f=1.5 would give realistic standard errors for the majority of stars. This factor compensates for too small formal errors of positions in the Tycho Catalogue (Cf. Sect 18.4 of Vol 4 of "The Hipparcos and Tycho Catalogues", ESA SP-1200, 1997). mas e_DEdeg s.e. of Dec at mean epoch number=3 The standard errors given are for the mean epoch. They are in the range 1.0-117.1. The standard errors at some epoch, t, are obtained as e_RA(t)* = sqrt((f*e_RA*)^2^ + ((e_pmRA*)*(t-epRA))^2^ ) and e_DE(t) = sqrt((f*e_DE)^2^ + (e_pmDE*(t-epRA))^2^ ) A factor f=1.5 would give realistic standard errors for the majority of stars. This factor compensates for too small formal errors of positions in the Tycho Catalogue (Cf. Sect 18.4 of Vol 4 of "The Hipparcos and Tycho Catalogues", ESA SP-1200, 1997). mas e_pmRA s.e. prop mot in RA * cos(dec) mas/a e_pmDE s.e. of proper motion in Dec mas/a BT Tycho BT magnitude number=4 The BT and VT photometry is copied from the Tycho Catalogue. Approximate Johnson photometry may be obtained as: V = VT -0.090*(BT-VT) B-V = 0.850*(BT-VT) Consult Sect 1.3 of Vol 1 of "The Hipparcos and Tycho Catalogues", ESA SP-1200, 1997, for details. mag e_BT s.e. of BT number=4 The BT and VT photometry is copied from the Tycho Catalogue. Approximate Johnson photometry may be obtained as: V = VT -0.090*(BT-VT) B-V = 0.850*(BT-VT) Consult Sect 1.3 of Vol 1 of "The Hipparcos and Tycho Catalogues", ESA SP-1200, 1997, for details. mag VT Tycho VT magnitude number=4 The BT and VT photometry is copied from the Tycho Catalogue. Approximate Johnson photometry may be obtained as: V = VT -0.090*(BT-VT) B-V = 0.850*(BT-VT) Consult Sect 1.3 of Vol 1 of "The Hipparcos and Tycho Catalogues", ESA SP-1200, 1997, for details. mag e_VT s.e. of VT number=4 The BT and VT photometry is copied from the Tycho Catalogue. Approximate Johnson photometry may be obtained as: V = VT -0.090*(BT-VT) B-V = 0.850*(BT-VT) Consult Sect 1.3 of Vol 1 of "The Hipparcos and Tycho Catalogues", ESA SP-1200, 1997, for details. mag Num Number of positions used number=5 Between 2 and 13 positions (TYC plus 1-12 AC positions) were used in the adjustment: Npos: 2 3 4 5 6 7 8 9 10 11 12 13 Stars: 20183 588096 312449 47150 18045 3169 742 217 81 33 14 3 --- q_pm quality flag for proper motion number=6 q_pm (0..9) gives twice the ratio of the estimated s.e. to the formal s.e. A large value may be taken as a warning. The value 9 marks proper motions deviating from HIP values by more than six combined standard errors. Separate values were computed for R.A. and Dec. Here the maximum value is given. The quality flag was computed prior to the adjustment of the standard errors (Cf Sect 3 of Hoeg et al. 1998). q_pm: 0 1 2 3 4 5 6 7 8 9 Stars 35082 271197 319970 183564 93971 45973 22662 11459 3494 2810 --- HD HD identifier from TYC --- HIP Hipparcos number from TYC --- CCDM CCDM component identifier from TYC number=7 The CCDM component identifier is only given for HIP stars. It is copied from field T51 of the Tycho Catalogue. --- Plx parallax for HIP stars number=8 The parallax for HIP stars is copied from field H11 of the Hipparcos Catalogue, but only when it exceeds the standard error. The HIP parallax was NOT used in the construction of the TRC. mas dupflg duplicity flag number=9 the duplicity flag is set for 16587 stars where duplicity was clearly indicated or suspected in the Tycho data, but not resolved. (T49 is D or S in TYC). --- varflg variability flag number=10 the variability flag is set for 18505 stars with known variability. (T47 set or T48='V' in TYC). --- ACTflg ACT flag number=11 ' ' = also in ACT, proper motion agrees within 10 mas/yr in both coordinates; 'T' = only in TRC (39892 stars); 'X' = also in ACT, does not agree within 10 mas/yr (19104 stars). --- rec Rec. numb. of 1st star in each region number=1 The catalogue is sorted according to the GSC region numbers. The line i of the index file gives the record number in TRC of the first star in GSC region i. Line i+1 gives the record number +1 of the last star in GSC region i. --- Claus Fabricius Niels Bohr Institute for Astronomy 1998Apr03 I_250.xml