Irregular Galaxy Aquarius Dwarf (DDO 210, AqrDIG, PGC 65367), type Im V,
The Aquarius Dwarf was apparently first cataloged in the DDO survey
(van den Bergh 1966). It was found to be a nearby
galaxy because of negative radial velocity (blueshift); it is approaching
us at 137 km/s. Yahil, Tammann and Sandage (1977)
identify it as one of six "New Probably Members of the Local Group,"
together with IC 10, Leo A,
IC 5152, the Pegasus Dwarf
- 20 : 46.8
- -12 : 51
- Im V
- 3400 kly
- Apparent Dimension:
- 2.3 x 1.2 arc min
- 13.9 m_v
- Abs. Mag:
According to Mike Irwin's group, the membership of this galaxy in the Local
Group is still doubtful. However, Sidney van den
Bergh (2000) regards this question as positively solved and Aquarius
Dwarf a confirmed Local Group member because of a distance derivation by
Lee et.al. (1999) who derive a distance of
950 kpc (3.1 million light-years) both from our Milky Way galaxy and from
the presumable barycenter of the Local Group, from the apparent magnitudes
of giant stars at the tip of the red giant branch. Adjusted for our Hipparcos
corrected distance for the Large Magellanic Cloud this
value becomes 3.4 million light-years.
The image in this page was obtained by
Nordic Optical Telescope (NOT) image of
the Aquarius Dwarf, taken by
A. Oksanen. This image was
Astronomy Picture of the Day (APOD) February 4, 1996 (but erroneously
assigned to SagDEG), and (correctly assigned) as
July 27, 2003.
- Lee, 1999.
- Sidney van den Bergh, 1966.
Luminosity Classifications of Dwarf Galaxies.
Astronomical Journal, Vol. 71, pp. 922-926
- Sidney van den Bergh, 2000.
Updated information on the Local Group.
- A. Yahil, G.A. Tammann, and Allen Sandage, 1977.
The Local Group: The Solar Motion Relative to its Centroid.
Astrophysical Journal, Vol. 217, pp. 903-915 (Nov 1, 1977)
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Last Modification: March 14, 1998