TABLE  tgas_source

Tycho-Gaia Astrometric Solution catalogue containing astrometric and photometric information for all isolated, single sources in the Tycho2 catalogue and observed by Gaia. For more information about TGAS, please see The Tycho-Gaia astrometric solution: how to get 2.5 million parallaxes with less than one year of Gaia data Required constraints: Primary key is (source_id)

Name	Type	Length	Unit	Description	Default Value	Unified Content Descriptor
hip	int	4		Hipparcos identifier		id.cross
tycho2_id	varchar	32		Tycho2 identifier		id.cross
solution_id	bigint	8		Solution identifier		meta.id;meta.version
source_id	bigint	8		Unique source identifier		meta.id;meta.main
random_index	bigint	8		Random index used to select subsets		meta.code
ref_epoch	float	8	Julian years	Reference epoch		meta.ref;time.epoch
ra	float	8	degrees	Celestial Right Ascension		pos.eq.ra;meta.main
ra_error	float	8	milliarcsec	Standard error of Right Ascension		stat.error;pos.eq.ra
dec	float	8	degrees	Celestial Declination		pos.eq.dec;meta.main
dec_error	float	8	milliarcsec	Standard error of Declination		stat.error;pos.eq.dec
parallax	float	8	milliarcsec	Parallax		pos.parallax
parallax_error	float	8	milliarcsec	Standard error of parallax		stat.error;pos.parallax
pmra	float	8	milliarcsec/year	Proper motion in Right Ascension direction		pos.pm;.pos.eq.ra
pmra_error	float	8	milliarcsec/year	Error of proper motion in Right Ascension direction		stat.error;pos.pm;.pos.eq.ra
pmdec	float	8	milliarcsec/year	Proper motion in Declination direction		pos.pm;.pos.eq.dec
pmdec_error	float	8	milliarcsec/year	Error of proper motion in Declination direction		stat.error;pos.pm;.pos.eq.dec
ra_dec_corr	real	4		Correlation between Right Ascension and Declination		stat.correlation
ra_parallax_corr	real	4		Correlation between Right Ascension and parallax		stat.correlation
ra_pmra_corr	real	4		Correlation between Right Ascension and proper motion in Right Ascension		stat.correlation
ra_pmdec_corr	real	4		Correlation between Right Ascension and proper motion in Declination		stat.correlation
dec_parallax_corr	real	4		Correlation between Declination and parallax		stat.correlation
dec_pmra_corr	real	4		Correlation between Declination and proper motion in Right Ascension		stat.correlation
dec_pmdec_corr	real	4		Correlation between Declination and proper motion in Declination		stat.correlation
parallax_pmra_corr	real	4		Correlation between parallax and proper motion in Right Ascension		stat.correlation
parallax_pmdec_corr	real	4		Correlation between parallax and proper motion in Declination		stat.correlation
pmra_pmdec_corr	real	4		Correlation between proper motion in Right Ascension and proper motion in Declination		stat.correlation
astrometric_n_obs_al	int	4		Total number of observations in the Along-Scan direction		meta.number
astrometric_n_obs_ac	int	4		Total number of observations in the Across-Scan direction		meta.number
astrometric_n_good_obs_al	int	4		Number of good observations in the Along-Scan direction		meta.number
astrometric_n_good_obs_ac	int	4		Number of good observations in the Across-Scan direction		meta.number
astrometric_n_bad_obs_al	int	4		Number of bad observations in the Along-Scan direction		meta.number
astrometric_n_bad_obs_ac	int	4		Number of bad observations in the Across-Scan direction		meta.number
astrometric_delta_q	real	4		Hipparcos/Gaia data discrepancy (Hipparcos subset of TGAS only)		stat.value
astrometric_excess_noise	float	8	milliarcsec	Excess noise of the source		stat.value
astrometric_excess_noise_sig	float	8		Significance of the excess noise		stat.value
astrometric_primary_flag	bit	1		Primary or secondary		meta.code
astrometric_relegation_factor	real	4		Relegation factor		arith.factor
astrometric_weight_al	real	4		Mean astrometric weight of the source Along-Scan		stat.weight;stat.mean
astrometric_weight_ac	real	4		Mean astrometric weight of the source Across-Scan		stat.weight;stat.mean
astrometric_priors_used	int	4		Type of prior used in the astrometric solution
matched_observations	smallint	2		Amount of observations matched to this source		meta.number
duplicated_source	bit	1		Source with duplicated sources
scan_direction_strength_k1	real	4		Degree of concentration of scan directions across the source
scan_direction_strength_k2	real	4		Degree of concentration of scan directions across the source
scan_direction_strength_k3	real	4		Degree of concentration of scan directions across the source
scan_direction_strength_k4	real	4		Degree of concentration of scan directions across the source
scan_direction_mean_k1	real	4	degrees	Mean position angle of scan directions across the source
scan_direction_mean_k2	real	4	degrees	Mean position angle of scan directions across the source
scan_direction_mean_k3	real	4	degrees	Mean position angle of scan directions across the source
scan_direction_mean_k4	real	4	degrees	Mean position angle of scan directions across the source
phot_g_n_obs	int	4		Number of observations contributing to G band photometry		meta.number
phot_g_mean_flux	float	8	electrons/s	G-band mean flux		phot.flux;stat.mean;em.opt
phot_g_mean_flux_error	float	8	electrons/s	Error on G-band mean flux		stat.error;phot.flux;stat.mean;em.opt
phot_g_mean_mag	float	8	mag	G-band mean magnitude		phot.mag;stat.mean;em.opt
phot_variable_flag	varchar	16		Photometric variability flag		meta.code;src.var
l	float	8	degrees	Galactic longitude		pos.galactic.lon
b	float	8	degrees	Galactic latitude		pos.galactic.lat
ecl_lon	float	8	degrees	Ecliptic longitude		pos.ecliptic.lon
ecl_lat	float	8	degrees	Ecliptic latitude		pos.ecliptic.lat
cx	float	8		unit vector of spherical co-ordinates		pos.distance;pos.cartesian.x
cy	float	8		unit vector of spherical co-ordinates		pos.distance;pos.cartesian.y
cz	float	8		unit vector of spherical co-ordinates		pos.distance;pos.cartesian.z
htmID	bigint	8		Hierarchical Triangular Mesh (HTM) index, 20 deep, for equatorial co-ordinates		pos.eq
Total length		392