Sextans Dwarf

Dwarf Spheroidal Galaxy Sextans Dwarf (Sextans Dwarf Elliptical Galaxy), type dE3, in Sextans

238 km/s (helioc.)
320 kly
Apparent Dimension:
90 x 65 arc min
8.4 kly
12. mag vis
Abs. Mag:
Sextans Dwarf was discovered in 1990 by Mike Irwin, P.S. Bunclark, M.T. Bridgeland, and R.G. McMahon as the 8th dwarf satellite galaxy of the Milky Way (Irwin 1990).

This galaxy was found within a comprehensive monitoring program of UKST sky survey plates with the APM measuring machine in Cambridge, UK. It lies within 10 degrees of the significantly more distant presumable Local Group galaxies Sextans A and Sextans B, and only 4 degrees from the Milky Way halo globular cluster Palomar 3, which had also been cataloged as Sextans C on occasions, which lies at a similar distance as this dwarf galaxy. There is, however, no confirmed evidence for a physical connection of that globular with the dwarf galaxy, which are physically separated by a distance of only about 30,000 light-years, in particular, as their radial velocities differ significantly: The Sextans Dwarf is receding from us at 238 km/s, globular cluster Palomar 3 at only 83 km/s.

According to the measurements at its discovery, the Sextans Dwarf, or Sextans Dwarf Elliptical Galaxy ("SexDEG"), or "Sextans DSph", extends over an angular diameter of 90 x 65 arc minutes, thus exhibiting an ellipticity of E4 or E3. At its distance of about 320,000 light-years, this corresponds to a linear diameter of 8,400 light-years along its major axis. Its core radius is determined, by best fit to a King profile, at 15 arc minutes, corresponding to 1,400 light-years. From its approximate, very rough overall brightness of +12 magnitudes, its absolute magnitude is estimated at about -8 Mag, one of the intrinsically faintest galaxies known.


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Hartmut Frommert
Christine Kronberg

Last Modification: March 14, 1998