5 Nov , 2008 by


Located south of the ecliptic plane, the constellation of Fornax was first introduced by Nicolas Louis de Lacaille under the name Fornax Chemica. It was later abbreviated to current name and adopted as one of the 88 modern constellations by the International Astronomical Union. Ranking at forty first in area, Fornax spans 398 square degrees of sky and consists of 2 main stars and 27 stars with Bayer/Flamsteed designations. It is bordered by the constellations of Cetus, Sculptor, Phoenix and Eridanus. Fornax is visible to all observers located between latitudes between +50° and ?90° and is best seen at culmination during the month of December.

Since Fornax wasn’t readily visible to the ancient Greeks and Romans, no real mythology surrounds this constellation. However, its name does represent the small solid-fuel heater formerly used for heating chemical experiments. Fornax is often referred to as the “Furnace” as well. In Roman mythology, Fornax was the goddess of bread and baking, although this has nothing to do with the constellation!

Let’s begin our tour of Fornax hot spots with binoculars and take a look at Alpha Fornacis – the “a” shape on our map. Its proper name is Dalim, and it is also a very easy visual binary star. Located about 46 light years from Earth, 4th magnitude Alpha Fornacis A is a subgiant star with a stellar luminosity about four times brighter than our Sun, while the 7th magnitude B star is a G-class dwarf star that only puts out about half as much light as Sol. Why such a great difference between the two? Mass is the answer. In this case the stellar mass is directly proportionate to the output of luminosity.

Now move on to Beta Fornacis – the “B” shape on our map. Beta is located about 170 light years from our solar system and it is a yellow giant star. Now hop west for Delta – the “8” shape. Here is a luminous blue variable star! Delta is located more than 700 light years from Earth. Would you like to enjoy another visual double star? Then drop south of Beta for Eta 2 Fornacis. It’s a pleasing pair in binoculars!

For galaxy hunters, Fornax is an absolute delight. It’s time to get out the telescope…

Let’s begin with NGC 1398 (RA 3:38.9 Dec -26:20). This barred spiral galaxy is quite bright for 10th magnitude and shows a surprisingly bright nucleus even in a smaller telescope. Believe it or not, it was originally found by Friedrick Weinnecke when he was searching for comets with a 4.5″ reflector! Don’t mistake the core for all of the galaxy… Use aversion to look for the full extent of the spiral galaxy structure of this beauty.

Now try NGC 1350 (RA 3:31.1 Dec -33:38). Also near 10th magnitude, this spiral galaxy is at home in the Fornax Galaxy Cluster. Hanging out some 55 million light years from Earth, it measures roughly 130,000 light years across, and it is slightly larger than the Milky Way Galaxy. Populated by young blue star clusters, the spiral arms of NGC 1350 seem to wrap around the galaxy’s large, bright nucleus – giving it a lazy appearance. It’s sometimes referred to as the “Colossal Cosmic Eye”.

Turn your sights towards NGC 1097 (RA 2:46.3 Dec -30:17), At near magnitude 9, this galaxy is even brighter! NGC 1097 is a barred spiral galaxy about 45 million light-years away from our solar system – and it’s one hot Seyfert galaxy, with jets shooting from the core. Like most galaxies, NGC 1097 has a supermassive black hole at its center. Around the central black hole is a ring of star-forming regions with a network of gas and dust that spirals from the ring to the black hole. NGC 1097 has two satellite galaxies. NGC 1097A is the largest of the two. It is a peculiar elliptical galaxy that orbits 42,000 light-years from the center of NGC 1097. NGC 1097B is the outermost one and not much is known about that.

One more? How about NGC 1316 (RA 3:22.7 Dec -37:12)? Even brighter yet, this lenticular galaxy is located about 70 million light-years away. Need music? Then turn it up because NGC 1316 is also known as Fornax A – a brilliant radio source. Francois Schweizer studied NGC 1316 extensively in the late 1970s. He found that the galaxy appeared to look like a small elliptical galaxy with some unusual dust lanes embedded within a much larger envelope of stars. The outer envelope contained many ripples, loops, and arcs. He also identified the presence of a compact disk of gas near the center that appeared inclined relative to the stars and that appeared to rotate faster than the stars. Based on these results, Schweizwer suggested that NGC 1316 was built up through the merger of several smaller galaxies. These merger events may have fueled the central supermassive black hole with gas, causing the galaxy to become a radio galaxy. He also states that NGC 1316 is comparable to the giant elliptical galaxies found in the centers of other clusters of galaxies. Using spectroscopy of its brightest globular clusters, the merger is estimated to have occurred over three hundred thousand years ago.

Before we leave the Furnace, let’s have a look at NGC 1360 (RA 3:33.3 Dec -25:51). Here we have one very bright planetary nebula! No one was really too sure of what it was until Rudolph Minkowski positively identified it. So what’s going on in this peculiar creature? Try a Wolf-Rayet star violently ejecting matter into a surrounding shell. Because larger telescopes sometimes reveal more color, you’ll soon understand how this one came about its nickname – the “Robin’s Egg Nebula”!

The constellation of Fornax contains a huge amount of galaxies, so please don’t stop here. Get yourself a good star atlas and let the “Furnace” heat up your observing nights!

Sources: Chandra Observatory, Wikipedia
Charts Courtesy of Your Sky.

Comments are closed.