Dwarf Spheroidal Galaxy NGC 185, type dE3 pec,
This galaxy was discovered (as a "Faint Nebula") by William Herschel on November
30, 1787, and cataloged by him as H II.707. His son John Herschel observed it
again and cataloged it as h 35 in his catalog of 1833, and as GC 90 in his
General Catalogue of 1864. They described it as follows:
- 00 : 39.0
- +84 : 20
- dE3 pec
- + 39 km/s
- 2300 kly
- Apparent Dimension:
- 14.5 x 12.5 arc min
- 9700 ly
- 9.2 m_vis
- Abs. Mag:
- - 15.8 Mag vis
A first photograph of NGC 185 was obtained by James Edward Keeler with the
Crossley Reflector of Lick Observatory between 1898 and 1900.
- Pretty bright, very large, irregularly round, very gradually much brighter
to the middle, resolvable, 5 or 6 [arc min] diameter (1789)
- Pretty bright; large; round; gradually brighter to the middle; full 60"
- Pretty bright; very large; irregularly round; very gradually much brighter
to the middle; barely resolvable [mottled] (1864)
NGC 185 was recognized as a Local Group member galaxy, together with its
neighbor NGC 147, by Walter
Baade (1944), when he resolved them into stars with the 100-inch reflector
on Mt. Wilson. These two dwarf elliptical galaxies apparently form a physical
pair, as they are only 58 arc minutes separated; according to
Van den Bergh, they are probably gravitationally
bound in a physical pair. Both are more remote satellite galaxies of the
Andromeda Galaxy M31, but are at a somewhat closer
distance to us these times. Modern distance estimates for NGC 185, adjusted for
the scale we use here, correspond to some 2.3 million light-years.
The image in this page was obtained by astronomers of the Isaac Newton Group
of Telescopes on La Palma, under the leadership of D. Martínez-Delgado,
in 1999. It is a combination of B, V, and R images from the Jacobus Kapteyn
Telescope. From this image, evidence was found that NGC 185 actually contains
young stellar clusters, which had been thought to be luminous, blue stars, by
their discoverer Walter Baade. According to research of these images, star
formation proceeded at a low rate until the recent past, the age of the most
recent traces of star formation activity detected in the galaxy being some 100
million years. These conclusions rule out the possibility of NGC 185 being an
old galaxy formed by Population II stars only.
Release of 21 December 1999
[local archival copy]
Hi-res (1000x1000 pixel) version of this image
- Baade, W., 1944.
NGC 147 and NGC 185, Two New Members of the Local Group of Galaxies.
Astrophysical Journal, Vol. 100, pp. 147-150
- D. Martínez-Delgado, A. Aparicio, C. Gallart, 1999.
The star formation history of the local group dwarf elliptical galaxy NGC
185. II. Gradients in the stellar population.
AJ, 118, 2229.
- Sidney van den Bergh.
The Binary Galaxies NGC 147 and NGC 185.
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Last Modification: December 5, 2005