NGC 5139

Globular Cluster in Centaurus

Information about NGC 5139

Basic object information

Object name: NGC 5139

Popular name: omega Centuri

Object type: Globular cluster

Magnitude: 3.9

Size: 55.0'

Position information

Apparent RA: 13h 27m 41s

Apparent Dec: -47° 33' 33"

Constellation: Centaurus

Altitude: -1° 48' 40"

Azimuth: 142° 55' 34"

Hour angle: 19h 47m 3s

Rise: 16h 20m 43s

Transit: 20h 23m 48s

Set: 0h 30m 52s

Names and designations

omega Centuri

NGC 5139

GCL 24

ESO 270-SC11

Omega Centauri

omega Cen

Star atlas chart numbers

Herald-Bobroff Astroatlas: Chart C-83

Millennium Star Atlas: Charts 953-954 (Vol II)

Sky Atlas 2000.0: Chart 21

Uranometria 2000: Chart 403, Vol 2

Revised NGC/IC Catalog Data

(Wolfgang Steinicke, Jan 2003)

Names and designations

NGC 5139

GCL 24

ESO 270-SC11

Catalog information

Type of object: Globular cluster

RA (J2000.0): 13h 26m 47.0s

Dec (J2000.0): -47° 28' 51"

V Magnitude: 3.9

Size: 55.0'

Classification: VIII

Remarks: Omega Cen

Saguaro Astronomy Club v7.2 Catalog Data

Saguaro Astronomy Club, August 2000

Names and designations

NGC 5139

Omega Centauri

Catalog information

Type of object: Globular cluster

RA (J2000.0): 13h 26m 48.0s

Dec (J2000.0): -47° 29' 00"

Constellation: Centaurus

Magnitude: 3.7

Size: 36.3'

Object classification: VIII

Description: !!!eL,B,eRi,vvC

Notes: Stars mags 11...;finest globular;magnificent object

Harris Globular Cluster Catalog Data

A catalog of parameters for globular clusters on the Milky Way, Harris W.E., Astron. J. 112, 1487 (1996, rev. 15 May 1997)

Names and designations

Cluster identification number: NGC 5139

Other commonly used cluster name: omega Cen

Position information

RA (J2000.0): 13h 26m 45.9s

Dec (J2000.0): -47° 28' 37"

Galactic longitude: 309.10°

Galactic latitude: 14.97°

Distance from the Sun: 5.1 kpc

Distance from the galactic centre: 6.3 kpc

Sun-centred position components:

X: 3.1 kpc (towards galactic centre)

Y: -3.8 kpc (in direction of galactic rotation)

Z: 1.3 kpc (towards north galactic pole)

Brightness and colour information

Foreground reddening: 0.12 magnitudes

V magnitude of the horizontal branch: 14.53

Apparent visual distance modulus: 13.92 magnitudes

Integrated V magnitude of the cluster: 3.68

Absolute visual magnitude: -10.24

Integrated B-V colour index: 0.78

Integrated V-R colour index: 0.51

Integrated V-I colour index: 1.05

Specific frequency of RR Lyr: 12.2

Dickens horizontal-branch morphological type: 2

Metallicity in log10 scale (Sun=1): -1.62

Integrated spectral type: F5

Radial velocity information

Heliocentric radial velocity: 232.3 km/sec

Observational uncertainty in heliocentric radial velocity: 0.5 km/sec

Radial velocity relative to Solar local standard of rest: 229.4 km/sec

Physical information

Central concentration [log10(Rt/Rc)]: 1.24

Core radius: 2.58 arc minutes

Half-mass radius: 4.18 arc minutes

Log (base 10) of core relaxation time: 9.76 yr

Log (base 10) of core relaxation time at the half-mass radius: 9.72 yr

Central surface brightness in V band: 16.77 mag/sq arc sec

Log (base 10) of central luminosity density: 3.13 solar luminosities per cubic parsec