Constellations: Fornax 'the Furnace' Content from the guide to life, the universe and everything

Constellations: Fornax 'the Furnace'

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The shield of the Science, Mathematics and Engineering faculty of the h2g2 University.Constellations: Overview | Andromeda | Antlia | Apus | Aquarius | Aquila | Ara | Aries | Auriga | Boötes | Caelum
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Name:Fornax (Latin: 'Furnace')
Short form:For
Originally:Fornax Chemica ('chemical furnace')
Area:398 sq deg
Co-ordinates1:Right Ascension 03h, Declination −30°

Fornax, 41st in size of the 88 internationally recognised constellations, is nestled into a bend of the constellation Eridanus, the river. It also shares borders with Cetus, Sculptor and Phoenix. Fornax is a modern constellation, created after 1754 by French astronomer Nicolas Louis de Lacaille (1713 - 62). In the mid-18th Century, Lacaille studied the stars of the southern hemisphere from the Cape of Good Hope, mapping over 10,000 stars and 42 nebulous objects, and formed 14 new constellations.

Fornax was originally named Fornax Chemica (Chemical Furnace). The last part has dropped out of use. It was named in honour of the French chemist Antoine Laurent Lavoisier who established that burning is a process that involves the combination of a substance with oxygen. He also demonstrated that water is formed from oxygen and hydrogen.

There are no Messier objects, no meteor showers and no bright stars in Fornax. But that doesn't mean there's nothing to interest the reader. This constellation has a planetary nebula, NGC 1360. Fornax also boasts a number of spectacular galaxies, including a really rich cluster of 58 galaxies called the Fornax Cluster.


The scientific star names are simple to understand (if you know your Greek alphabet). For example: 'alpha Fornacis' means it's the brightest star in the constellation Fornax. The next brightest is designated 'beta', and so on. Combined with the genitive name, this is known as the 'Bayer designation'. Alpha Fornacis is a binary star system that's just 46 light years2 away. UDF 2457 is a red dwarf some 59,000 light years distant. Identified on the Hubble Ultra Deep Field (UDF), it is one of the furthest-known stars which reside in the Milky Way.

Star Table

(light years)
Spectral classification
and/or comments
α Foralpha Fornacis+3.8 var46Binary star system
β Forbeta Fornacis+4.45170Double star system
γ Forgamma Fornacis+4.68 var360Blue-white main sequence
δ Fordelta Fornacis+5.0700Blue-white giant
λ2 Forlambda2 Fornacis+5.78 var81Yellow dwarf/has a planet
UZ For(AB)UZ Fornacis(AB)+18 var-Eclipsing binary cataclysmic variable with planetary system
UDF 2457UDF 2457+2559,000Red dwarf

New General Catalogue (NGC)

The NGC was compiled by John Louis Emil Dreyer (the director of the Armagh Observatory from 1882 - 1916).

NGC 1097 is a Seyfert galaxy. This type of galaxy, identified in 1943 and named after their discoverer Carl Keenan Seyfert, have an intensely bright, compact and highly active nucleus, caused by a supermassive black hole at their core. NGC 1097 has a companion galaxy 42,000 light years from its centre, and one of the larger galaxy's spiral arms seems to be embracing it. The galaxies will eventually merge, over millions of years.

NGC Galaxy Table

Catalogue numberGalaxy typeBrightness (m)Distance
(light years)
NGC 1097
(Arp 77)
Barred Seyfert CW spiral+10.245m
NGC 1316
(Fornax A)
Post-merger elliptical+9.459m
NGC 1350CW spiral+11.285m
NGC 1365Barred CW spiral+10.360m
NGC 1380Lenticular+10.961m
NGC 1381Lenticular+12.361m
NGC 1398ACW barred spiral+10.655m
NGC 1399Elliptical+10.560m
NGC 1404Elliptical+10.960m
NGC 1427Elliptical+11.870m
NGC 1427ABarred irregular+13.462m

Other Galaxies

Fornax Dwarf

Fornax Dwarf is a spheroidal galaxy which orbits the Milky Way. There are several globular clusters (tightly packed balls of stars) orbiting it.

Luminous Blue Compact Galaxy

J033728.8-352708 is a Luminous Blue Compact type galaxy (LBCG) that’s so distant it registers a redshift of 0.08. If an object is travelling away from us quickly enough, the light waves from it are stretched out, making visible light appear redder than it actually is, hence 'redshift'. The expansion of the Universe means that more distant objects are travelling away from us quicker. A redshift of 0.08 gives us a rough distance of a billion light years. We are seeing the light from its cosmic history - that is, the object was there a billion years ago, it may no longer be there, but we have no way of knowing. Now that's a galaxy that's far, far away!

Extrasolar Planets in Fornax

There has been several extrasolar planetary systems found in the constellation Fornax. HIP 13044 b is interesting because it is the first detected extrasolar planet which originated from another galaxy, now absorbed into the Milky Way.

HD 20781 and HD 20782 are a binary pair separated by over 9,000 AU (astronomical units - 1 AU is equivalent to Earth/Sun distance). Both stars host planetary systems. HD 20782 is similar in temperature and mass to our own Sun. Its solo planet is a gas giant in a highly eccentric orbit. The companion HD 20781 has two Neptune-mass planets which orbit so close to their parent star (both within Mercury's orbit in our Solar System) that they are classified 'hot'.

UZ Fornacis(AB) is a cataclysmic variable binary system made up of a white dwarf and a red dwarf which orbit each other in just over two hours. The white dwarf is constantly stripping the donor red dwarf of stellar material, which may end up causing a supernova. This complex and volatile system is host to two circumbinary superjovian worlds.

Figures given in the table below are the length of the planet's orbital period around its parent star, which we know of as a year. The mass of the extrasolar planet is compared with that of Jupiter, our solar system's largest planet. This is known by astronomers as the 'Jovian scale'.

Extrasolar Planets Table

Star name or
catalogue number
catalogue number
Planet mass
(Jovian scale)
Orbital period
(Earth days)
Year of discoveryComments
HD 20781HD 20781 b0.04292011'Hot Neptune'
HD 20781HD 20781 c0.05852011'Hot Neptune'
HD 20782HD 20782 b2.035862006Gas giant; high eccentric orbit
HD 20868HD 20868 b1.99380.852008Superjovian; habitable zone
lambda2lambda2 b0.0717.22009'Hot Neptune'
WASP-72WASP-72 b1.552.222013Hot gas giant
UZ For(AB)UZ For(AB) c6.35,8002010Superjovian
UZ For(AB)UZ For(AB) d7.71,9002011Superjovian

Hubble Ultra Deep Field

The famous Hubble Ultra Deep Field is the deepest view of the universe ever seen. It contains images of galaxies which formed 13 billion years ago, roughly 95% of the current age of the universe. It took over ten weeks of gazing at the same area in Fornax to capture the complete vista of galaxies. The Hubble Ultra Deep Field will be studied by many researchers eager to learn about the early universe.

1Current IAU guidelines use a plus sign (+) for northern constellations and a minus sign (−) for southern ones.2A light year is the distance light travels in one year, roughly 5.88 trillion miles or 9.46 trillion km.

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