Mercer 3, also known as GLIMPSE-C02, is a heavily obscured globular cluster embedded in the disk of the Milky Way galaxy. It was discovered in 2008 in the data obtained by

2MASS The Two Micron All-Sky Survey, or 2MASS, was an astronomical survey of the whole sky in infrared light. It took place between 1997 and 2001, in two different locations: at the U.S. Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona, and ...

and

GLIMPSE Glimpse or Glimpses may refer to: * Glimpse: Live Recordings from Around the World, an album by Sonicflood * ''The Glimpse'', an album by Robert Mitchell * Glimpse EP, an album by Trapt *Glimpse (software), a photo editor forked from GIMP GLIMPS ...

infrared surveys, and independently characterized by two groups. The cluster is located in the

Scutum The ''scutum'' (; plural ''scuta'') was a type of shield used among Italic peoples in antiquity, most notably by the army of ancient Rome starting about the fourth century BC. The Romans adopted it when they switched from the military formati ...

constellation. It had avoided detection for such a long time due to the extremely strong foreground

extinction Extinction is the termination of a kind of organism or of a group of kinds ( taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed ...

in its direction reaching 24 magnitudes in the visible light. Mercer 3 is probably situated at the distance from 4 to 8 kpc from the Sun and has a half-light radius of 0.7–1.5 pc. Mercer 3 is an old globular cluster having the age of about 12 billion years. The mass of cluster is estimated at 2–3 hundred thousand

solar mass The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass o ...

es. It is among the most

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typi ...

-rich galactic globular clusters known.

References

{{DEFAULTSORT:Mercer 3 Globular clusters Scutum (constellation)