Sextans Dwarf

RA:

10:13.2

Dec:

-01:37

Type:

dE3

RV:

238 km/s (helioc.)

Distance:

320 kly

Apparent Dimension:

90 x 65 arc min

Diameter:

8.4 kly

Brightness:

12. mag vis

Abs. Mag:

Mass:

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.

References:

• Mike J. Irwin, P.S. Bunclark, M.T. Bridgeland, and R.G. McMahon, 1990. A new satellite galaxy of the Milky Way in the constellation of Sextans. Monthly Notices of the Royal Astronomical Society, Vol. 244, pp. 16P-19P, Short Communications from May 15, 1990 [ADS: 1990MNRAS.244p..16I]

Last Modification: March 14, 1998