Mercer 3

Mercer 3
2MASS image of Mercer 3
Observation data (J2000 epoch)
Constellation	Scutum
Right ascension	18^h 18^m 30^s[1]
Declination	−16° 58′ 36″[1]
Distance	13–26 kly (4–8 kpc[1])
Apparent magnitude (V)	not visible
Apparent dimensions (V)	39″ (half-light diameter)[1]
Physical characteristics
Mass	2–3 × 10^5 M☉
Radius	2–5 ly
Estimated age	12 Gyr[1]

Mercer 3 is a heavily obscured globular cluster embedded in the disk of the Milky Way galaxy.^[1] It was discovered in 2008 in the data obtained by 2MASS and GLIMPSE infrared surveys. The cluster is located in the Scutum constellation. It had avoided detection for such a long time due to the extremely strong foreground extinction 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.^[1]

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 masses.^[1]

References

1. Strader, J.; Kobulnicky, H. A. (2008). "A Probable New Globular Cluster in the Galactic Disk". The Astronomical Journal 136 (5): 2102. arXiv:0808.1719. Bibcode:2008AJ....136.2102S. doi:10.1088/0004-6256/136/5/2102.