The cluster is centered about 2,050
light years away. Estimates for the number of its members range from 169[9] up to 414, with a directly-counted mass of 1,206
M☉; 1,332 M☉ by application of the
virial theorem.[4] The cluster is around 330 million years old with a near-solar
metallicity of [Fe/H] = −0.04.[5] The brightest component (lucida) is of magnitude 9.3.[10] Five of the cluster members are candidate
red giants,[11] while orange
variable VV Sgr in the far south,[b] is a candidate
asymptotic giant branch star.[12]
A 6th-magnitude star, shown in the top-right corner, figures in the far north-west as a foreground star – HD 163245 (HR 6679). Its
parallax shift is 9.8912±0.0518
mas, having taken into account
proper motion, which means it is about 101 parsecs (330 ly) away.[13]
^
abcMcNamara, B. J.; Sanders, W. L. (February 1983), "A virial mass determination of the open cluster NGC 6494", Astronomy and Astrophysics, 118 (2): 361–362,
Bibcode:
1983A&A...118..361M.
^Ridgway, S. T.; et al. (February 1979), "Twenty-eight angular diameters for late-type stars by the lunar occultation technique", Astronomical Journal, 84: 247–256,
Bibcode:
1979AJ.....84..247R,
doi:10.1086/112414. See VV Sgr.
^Sanders, W. L.; Schroeder, R. (August 1980), "Membership in the open cluster NGC 6494", Astronomy and Astrophysics, 88: 102–107,
Bibcode:
1980A&A....88..102S.
^Sanders, W. L. (September 1990), "UBV photometry of NGC 6494 and metallicity considerations", Astronomy and Astrophysics Supplement Series, 84 (3): 615–618,
Bibcode:
1990A&AS...84..615S.
^Claria, J. J.; Lapasset, E. (November 15, 1989), "Multicolour photometry of red giants in three southern open clusters", Monthly Notices of the Royal Astronomical Society, 241 (2): 301–310,
Bibcode:
1989MNRAS.241..301C,
doi:10.1093/mnras/241.2.301