Release 11.12 ("Hergest Ridge")

The meaning of the columns of the database is the same that in the database of William E. Harris
(values mainly come from Harris 2003 and Harris 2010, details here)

Namely, the different colums give:  

Part 1. Identification and Positional Data

ID Cluster identification number NGC 104
Name Other commonly used cluster name 47 Tuc 
RA Right ascension (J2000) (not shown on Table I) 00 24 05.2
DEC Declination (J2000) (not shown on Table I) -72 04 51 
l Galactic longitude (degrees)  305.90
b Galactic latitude (degrees) -44.89
R_Sun Distance from Sun (kiloparsecs) 4.5
R_gc Distance from Galactic center (kpc), assuming R_0=8.0 kpc 7.4
X Distance components X in Sun-centered coordinate system; X points toward Galactic center 1.9
Distance components Y in Sun-centered coordinate system : Y points in direction of Galactic rotation -2.6 
Z Distance components Z in Sun-centered coordinate system: Z toward North Galactic Pole -3.2

Part II. Photometric Parameters

ID Cluster identification NGC 104
E(B-V) Foreground reddening 0.04
V_HB V magnitude level of the horizontal branch (or RR Lyraes) 14.06
(m-M)V Apparent visual distance modulus 13.37
V_t Integrated V magnitude of the cluster 3.95
M_Vt Absolute visual magnitude (cluster luminosity) -9.42
U-B Integrated color indices  (U-B) (uncorrected for reddening) 0.37
 B-V Integrated color indices (B-V) (uncorrected for reddening) 0.88
V-R Integrated color indices (V-R) (uncorrected for reddening) 0.53 
V-I Integrated color indices (V-I) (uncorrected for reddening) 1.14
S_RR Specific frequency of RR Lyrae variables 0.3
HBR Horizontal-branch ratio, HBR = (B-R)/(B+V+R) -0.99
hbt Dickens horizontal-branch morphological type


Part III:  Metallicity, Kinematics, and Structural Parameters

ID  Cluster identification NGC 104
[Fe/H]  Metallicity [Fe/H] -0.76
SpT  Integrated spectral type G4 
v_r Heliocentric radial velocity (km/s) -18.7
+/-  Observational (internal) uncertainty in radial velocity 0.2
v_LSR Radial velocity relative to Solar local standard of rest -28.0
c Central concentration, c = log(r_t/r_c) 2.03
r_c Core radius in arcmin 0.44
r_h  Half-mass radius in arcmin 2.79
r_t Tidal radius in arcmin 47.25
lg(tc) Logarithm of core relaxation time, in log_10(years) 8.06
lg(th Logarithm of relaxation time at the half-mass radius, in log_10(years) 9.48
mu_V Central surface brightness, V magnitudes per square arcsecond 14.43
rho_0 Logarithm of central luminosity density (Solar luminosities per cubic parsec 4.77

Top of the page

Home | Parameters | Table 1 | Table 2 | Table 3
Search | Feedback | What's new | Links | Blog