IC 1257

RA:

17:27:08.5

Dec:

-07:05:35

Distance from Sun:

81.5 kly

Distance from Galactic Center:

58.4 kly

Apparent Diameter:

arc min

Brightness:

13.10 mag vis

Radial Velocity:

-140.2 +/- 2.1 km/s

Diameter:

ly

Abs. Mag:

-6.15 Mag vis

On the ground of its discovery by Rudolf Ferdinand Spitaler, this object was included by Dreyer in his first Index Catalogue as IC 1257, and longly referred to as an open cluster, although R. Burnham, Jr. remarked that its classification may be uncertain. It was finally revealed as a globular cluster only in 1997 (Harris et.al., 1997), making it Milky Way Globular Cluster No. 147.

Identification as a globular was done by obtaining a color-magnitude diagram, which immediately revealed its nature as a globular beyond the Galactic Center. IC 1257 is at a distance of 81,500 light years from our Sun and about 58,400 light years from the Galactic Center. It is approaching us at about 140 km/sec.

• Solution of the IC 1257 puzzle, NGC/IC Project
• Catalog of Variable Stars in IC 1257 (Christine Clement)

• Robert Burnham, Jr., 1978. Burnham's Celestial Handbook, vol. 2, p. 1231.
• William E. Harris, Randy L. Phelps, Barry F. Madore, Olga Pevunova, Brian A. Skiff, Czernik Crute, Barbara Wilson and Brent A. Archinal, 1997. IC 1257: A New Globular Cluster in the Galactic Halo. Astronomical Journal, Vol. 113, p. 688-691 (Feb 1997) [ADS: 1997AJ....113..688H]