Tycho-2 TDSC Merge (gaiadr3.tycho2tdsc_merge)

The table has 2561886 rows, 53 columns.

Description

Tycho-2 merged with the TDSC catalog and TDSC supplement.The Tycho Double Star Catalogue, (TDSC, ) contains 98482 components of double and multiple systems processed in the Tycho-2 context. It includes either original Tycho-2 data or results from a dedicated re-processing aimed at binaries. As pointed out by P. Marrese (personal communication), the TDSC star with identifier 29583 is redundant and it was therefore skipped. The TDSC supplement contains data from an additional 4777 components from either Hipparcos or Tycho-1.The Tycho-2 main catalogue  contains 2539913 sources, including many binaries, but a minimum separation of 0.8 arcsec was imposed during the catalogue construction. The Tycho-2 supplement-1 contains data for 17588 Hipparcos and Tycho-1 stars, which do not appear in the main catalogue, but only the 4777 stars relevant for TDSC are included here. The Tycho-2 supplement-2 contains an additional 1146 Tycho-1 stars of poor quality.We have merged Tycho-2 (main) with the TDSC main and supplement, keeping the Tycho-2 data model and extending it to include TDSC–specific fields. This is only possible to a certain degree as specified in detail below. In particular, Tycho-2 includes fields for mean position, proper motion etc. for a combination of Tycho-2 and several ground based catalogues. These fields are inherited for TDSC main stars, but were not derived for the TDSC supplement, where we only provide HIP proper motions. For Tycho-2 stars not in TDSC, blank TDSC fields were appended.For Tycho-2 stars in TDSC, the following fields were replaced by the corresponding TDSC fields:

  • tyc1, tyc2, tyc3;
  • hip;
  • ccdm.
In addition, if the TDSC contains a new solution:
  • btMag, eBtMag, vtMag, eVtMag, raDeg, deDeg, epRa1990, epDe1990, eRaDeg, eDeDec;
  • The mean position flag, pflag, is set to ‘P’ (“photocentre") if resolved and there are Tycho-2 mean positions. Mean position etc. are then repeated for both new components;
  • The proximity indicator, prox, is set to blank if the Tycho-2 star was resolved in TDSC;
  • The type-of-solution flag, posflg, set to ‘N’;
  • For resolved Tycho-2 stars, two records are given.
For the few TDSC stars with new solutions, but not in Tycho-2, and for the TDSC supplement stars (Hipparcos or Tycho-1), the Tycho-2 part of the merged record was populated in the following way:
  • TYC1..3 from TDSC;
  • pflag set to TDSC pmflg (‘H’ or ‘X’), ‘H’ indicating Hip proper motions;
  • no mean position and related fields;
  • proper motions only for Hipparcos stars;
  • BT, VT photometry from TDSC;
  • Tycho-1 flag, tyc, is set to posflg, i.e. ‘T’ or ‘H’ although Hipparcos stars may well be in Tycho-1;
  • Hipparcos, hip, and CCDM, ccdm, identifiers from TDSC;
  • astrometry from TDSC, but the (ra, dec)-correlation, corr, is set to blank.
New TDSC specific fields added after the Tycho-2 part of the record:
  • sysNo, cmp, nMain, nSup, magflg, wds, note, hd;
  • rcmp, pa, sep, ePa, ePaSep, eSep.

Attribution

If you have used Gaia data in your research, please use the following acknowledgement:

This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.

More information can be found on the credit and citation instructions page.

Columns

Name Type UCD Unit Description
id char meta.id
meta.main
Tycho-2 identifier
hip integer meta.id.cross Hipparcos number
tyc1 char meta.id.part
meta.main
TYC1 component from TYC or GSC
tyc2 char meta.id.part
meta.main
TYC2 component from TYC or GSC
tyc3 char meta.id.part
meta.main
TYC3 component from TYC or TDSC
id_tycho long meta.id
meta.dataset
Numeric Tycho-2 identifier
tyc char meta.code Tycho-1 star
ra double pos.eq.ra deg Observed Tycho-2 Right Ascension, ICRS
dec double pos.eq.dec deg Observed Tycho-2 Declination, ICRS
ra_deg double pos.eq.ra deg Observed Tycho-2 Right Ascension, ICRS
de_deg double pos.eq.dec deg Observed Tycho-2 Declination, ICRS
ra_mdeg double pos.eq.ra deg Mean Right Ascension, ICRS, epoch=J2000
de_mdeg double pos.eq.dec deg Mean Declination, ICRS, at epoch=J2000
pm_ra float pos.eq.ra
pos.pm
mas.yr**-1 Proper motion in RA*cos(dec)
pm_de float pos.eq.dec
pos.pm
mas.yr**-1 Proper motion in Dec
ep_ra1990 float time.epoch yr Epoch--1990 of raDeg
ep_de1990 float time.epoch yr Epoch--1990 of deDeg
ep_ra_m float time.epoch yr Mean epoch of RA.
ep_de_m float time.epoch yr Mean epoch of Dec.
num short meta.number Number of positions used for forming mean data
e_ra_deg double stat.error mas Uncertainty RA*cos(dec), of observed Tycho-2 RA.
e_de_deg double stat.error mas Uncertainty of observed Tycho-2 Dec.
corr double stat.correlation
pos.eq.ra
pos.eq.dec
Correlation (RAdeg,DEdeg)
e_ra_mdeg double stat.error mas Uncertainty RA*cos(dec),at mean epoch.
e_de_mdeg double stat.error mas Uncertainty of Dec at mean epoch.
e_pm_ra float stat.error mas.yr**-1 Uncertainty proper motion in RA*cos(dec).
e_pm_de float stat.error mas.yr**-1 Uncertainty of proper motion in Dec.
q_ra_mdeg float meta.code.qual Goodness of fit for mean RA
q_de_mdeg float meta.code.qual Goodness of fit for mean Dec
q_pm_de float meta.code.qual Goodness of fit for pmDe
q_pm_ra float meta.code.qual Goodness of fit for pmRa
pflag char meta.code Mean position flag
posflg char meta.id
stat.fit
Type of Tycho-2 solution
ccdm char meta.code.multip CCDM component identifier for HIP stars
prox short meta.code 100mas Proximity indicator
bt_mag float phot.mag
em.opt.B
mag Tycho-2 BT magnitude
vt_mag float phot.mag
em.opt.V
mag Tycho-2 VT magnitude
e_bt_mag float stat.error mag Uncertainty of BT
e_vt_mag float stat.error mag Uncertainty of VT
sys_no integer meta.id TDSC identifier for the system
cmp char meta.id.part Component designation
n_main short meta.number Number of components in TDSC main catalogue
n_sup short meta.number Number of components in the TDSC supplement
magflg char meta.code TDSC photometry flag
wds char meta.id.cross WDS identifier for the system
note char meta.note TDSC notes
hd integer meta.id.cross HD identifier for TDSC entries
rcmp char meta.id.assoc Reference component for position angle and separation
pa float pos.posAng deg Position angle
sep float pos.angDistance arcsec Separation
e_pa float stat.error deg Uncertainty of the position angle
e_pa_sep short stat.error Uncertainty of the position angle * separation
e_sep short stat.error mas Uncertainty of the separation