absolute magnitude

Since WEBDA provides the distance modulus [mu] and the colour excess or reddening E(B-V) for each cluster, it is possible to generate HRDs for each cluster by calculating the absolute visual magnitude Mv and the intrinsic colour index [(B-V).sub.0] for each star using the formulae

Fact sheet: the Sun Age (years) 4.5 x [10.sup.9] Mass (kg) 1.9891 x [10.sup.30] Diameter (km) 1.392 x [10.sup.6] Escape velocity (km x [s.sup.-1]) 617.7 Luminosity (watt) 3.846 x [10.sup.26] Mass conversion rate (kg x [s.sup.-1]) 4.3 x [10.sup.9] Absolute visual magnitude +4.83 Apparent visual magnitude -26.74 Distance from Earth (km) 1.47-1.52 x [10.sup.8] Core pressure (atmosphere) 2.452 x [10.sup.11] Core temperature ([degrees]C) 1.571 x [10.sup.7] Rotation period at equator (days) 26.8 Rotation period at poles (days) 36 Composition (% H, He) 92.1, 7.8 Table 1.

In visible light, the distance implies that the object peaked at a luminosity of 2 [yen] 1016 Suns, or absolute visual magnitude -36.5.

Quick facts about the Sun Age (years) 4.5 x [10.sup.9] Mass (kg) 1.9891 x [10.sup.30] Diameter (km) 1.392 x [10.sup.6] Escape velocity (km x [s.sup.-1]) 617.7 Luminosity (watt) 3.846 x [10.sup.26] Mass conversion rate (kg x [s.sup.-1]) 4.3 x [10.sup.9] Spectral type G2 V Absolute visual magnitude +4.83 Apparent visual magnitude -26.74 Distance from Earth (km) 1.47-1.52 x [10.sup.8] Core pressure (atmosphere) 2.452 x [10.sup.11] Core temperature ([degrees]C) 1.571 x [10.sup.7] Rotation period at equator (days) 26.8 Rotation period at poles (days) 36 Composition (% hydrogen) 92.1 Composition (% helium) 7.8 Table 2.

With an absolute visual magnitude of 10.5 it emits only 1/180 the light of the Sun.