planet – probably two. It is smaller and less luminous
than ÙCeti, and is in fact the feeblest star visible with the
naked eye apart from the far-southern ÂIndi. Its absolute
magnitude is 6.1, so that from our standard distance of
32.6 light-years it could not easily be seen without any
optical aid.
The two Omicrons, Ô^1 (Beid) and Ô^2 (Keid), lie side by
side, but are not connected. Beid is 277 light-years away
and well over 150 times as luminous as the Sun, while
Keid is a complex system only 16 light-years away. It is
a wide, easy binary; the secondary is itself a binary con-
sisting of a feeble red dwarf, of exceptionally low mass
(no more than 0.2 that of the Sun) together with a white
dwarf whose diameter is about twice that of the Earth and
which seems to be associated with a third body of sub-
stellar mass.
Fornaxis a ‘modern’ group whose name has been short-
ened. (There are other cases too: for example, Crux
Australis, the Southern Cross, is catalogued officially sim-
ply as ‘Crux’.) It was added to the sky by Lacaille in
1752; it was originally Fornax Chemica, the Chemical
Furnace.
It is marked by a triangle of inconspicuous stars: ·
(magnitude 3.87), ‚(4.46) and Ó(4.69). It is crowded with
galaxies, but all these are inconveniently faint for users of
small telescopes. ·is a wide double.STAR MAP 15
BRIGHTEST STARS
No. Star R.A. Dec. Mag. Spectrum Proper name
hm s ° ‘ “
16 ‚ 00 43 35 17 59 12 2.04 K0 Diphda
92 · 03 02 17 04 05 23 2.54 M2 Menkar
31 Ë 01 08 35 10 10 56 3.45 K2
86 Á 02 43 18 03 14 09 3.47 A2 Alkaffaljidhina
52 Ù 01 44 04 15 56 15 3.50 G8
Also above magnitude 4.3: È(3.56), ı(3.60), ̇(3.73), ̆(4.00), ‰(4.07), (4.25), Ì(4.27), Í^2 (4.28).
The variable Mira (ÔCeti) has been known to rise to magnitude 1.6, but most maxima are much fainter than this.
VARIABLES
Star R.A. Dec. Range Type Period Spectrum
hm °’ (mags) (d)
Ô 02 19.3 02 58 1.6–10.1 Mira 331 M
T0021.8 20 03 5.0–6.9 Semi-reg. 159 M
DOUBLES
Star R.A. Dec. P.A. Sep. Mags
hm °’ ° ”
̄ 01 49.6 10 41 250 183.8 4.9, 6.9
Á 02 43.3 03 14 294 2.8 3.8, 7.3
66 02 12.8 02 24 234 16.5 5.7, 7.5
Ô 02 19.3 02 58 085 0.3 var, 9.5v
CLUSTERS AND NEBULAE
MCNGC R.A. Dec. Mag. Dimensions Type
hm °’ ’
77 1068 02 42.7 00 01 8.8 6.9 5.9 SBp galaxy
(Seyfert galaxy)
62 247 00 47.1 20 46 8.9 20.0 7.4 Spiral galaxyBRIGHTEST STARS
No. Star R.A. Dec. Mag. Spectrum Proper name
hm s ° ‘ ”
67 ‚ 05 07 51 05 05 11 2.79 A3 Kursa
34 Á 03 58 02 13 30 31 2.95 M0 Zaurak
Also above magnitude 4.3: ‰(Rana) (3.54), Ù^4 (Angetenar) (3.69), Â(3.73), ̆^2 (Theemini) (3.82), 53 (Sceptrum) (3.87),
Ë(Azha) (3.89), Ó(3.93), Ì(4.09), Ô^1 (4.02), Ô^3 (Beid) (4.04), Ï(4.27); Ô^2 (Keid), close to Ô^1 , is of magnitude 4.43.
̇(Zibal), now of magnitude 4.80, is one of the few stars to be strongly suspected of fading during historic times,
though the evidence is inconclusive.
DOUBLE
Star R.A. Dec. P.A. Sep. Mags
hm °’ ° “
Ô^204 15.2 07 39 107 82.8 4.9, 9.5 B is doubleThe brightest star in Fornax is ·: R.A. 03h 12m 04s.2, dec. 28° 59’ 13”, mag. 3.87.
There are no other stars above magnitude 4.3.
DOUBLE
Star R.A. Dec. P.A. Sep. Mags
hm °’ ° “
· 03 12.1 28 59 298 4.0 4.0, 7.0 Binary 314yCETUSERIDANUSFORNAX M77 is a type Sb spiral
galaxy in the constellation
Cetus. A Seyfert galaxy, it
shows broad and strong
emission lines due to high
velocity gas in the galaxy’s
inner regions. Cetus A, a
strong radio source, is
situated in the nucleus of
the galaxy.Gb Atl of Univ Phil'03stp 2/4/03 7:42 pm Page 247