Fornax Dwarf

Dwarf Spheroidal Galaxy Fornax Dwarf (E356-G04, PCG 10093, A0237), type dSph/E2, in Fornax

[For Dw image]

RA:
02 : 39.9
Dec:
-34 : 32
Type:
dE2
RV:
+53 km/s
Distance:
500 kly
Apparent Dimension:
17.0 x 12.6 arc min
Diameter:
Brightness:
9.3 mag vis
Abs. Mag:
- 13.5 vis
Mass:
Fornax dwarf was discovered in 1938 by Harlow Shapley shortly after the Sculptor dwarf. He discovered this low surface brightness galaxy on photographic plates taken with the 24-inch reflector of the Harvard HCO Southern Station 24 at Boyden Observatory, South Africa.

Our image shows the Fornax dwarf in a 4-degree field, taken from the Digital Sky Survey and processed by Nils Sjölander.

  • Nils Sjölander's collection of Fornax dwarf materials

    This small and little conspicuous galaxy is an ellipsoidally shaped swarm of old stars which are at least almost all of population II, which formed about the same time as the galaxy and are similar to those in globular clusters. This is typical for dwarf elliptical or dwarf spheroidal galaxies, of which the Fornax Dwarf is a representative. Comparing, this galaxy is about 50 times larger than the largest globular clusters, but of a very much lower density; this is the reason that it is so difficult to be observed. Fornax is elongated along NE-SW. The brightest individual stars are about 19th magnitude; their distribution is very uniform, and there is little concentration toward a nucleus.

    The Deep Sky Field Guide to Uranometria gives slightly deviating data for visual brightness and dimension of this galaxy: 8.1 mag visual, and 12.0 x 10.2 arc minutes.

    The Fornax Dwarf has six globular clusters, the brightest of which was discovered much earlier than its parent galaxy: NGC 1049, for which Burnham gives visual mag 12.9 and an integrated spectral type F0, while the RASC Deep Sky Challenge Objects list has it at 11.0 and gives its apparent size as 0.6 arc min, the Deep Sky Field Guide to Uranometria 2000.0 has it at mag 12.9 and dimension 0.4 arc min. Four of the other Fornax Dwarf globulars are of magnitudes 13.7, 13.9, 14.1, and 16.6, according to Burnham (who didn't know of the sixth Fornax globular). Investigations of these globulars have been used to estimate the distance of this galaxy as 630,000 lightyears. More current estimates, adjusted for the scale we use here (e.g., with corrections based on results of ESA's Hipparcos astrometrical satellite), yield values of about 500,000 light-years (Mike Irwin's value of 427,000 ly corresponds to 477,000 ly in our scale, van den Berg's 456,000 to 500,000 ly, and Mateo's 450,000 are adjusted to 503,000 ly).

  • Fornax Dwarf visual observation - Andrew Murrell (IAAC) - All Fornax Dwarf observations in IAAC

    References



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    Last Modification: January 8, 2000