Fornax is a constellation in the southern sky, partly ringed by the celestial river Eridanus. Its name is Latin for furnace. The constellation Eridanus borders Fornax to the east, north and south, while Cetus, Sculptor and Phoenix gird it to the north, west and south respectively. Covering 397.5 square degrees and 0.964% of the night sky, it ranks 41st of the 88 constellations in size. In the equatorial coordinate system, the right ascension coordinates of Fornax lie between 01h 45m 24.18s and 03h 50m 21.34s, while the declination coordinates are between -23.76° and -39.58°. The whole constellation is visible to observers south of latitude 50°N.
Fornax was portrayed under the name Apparatus Chemicus in the Uranographia of Johann Bode (1801). Bode depicted it as Antoine Lavoisier’s experiment to decompose water into hydrogen and oxygen.
[http://www.ianridpath.com/startales/fornax.htm]
Fornax was introduced by Nicolas Louis de Lacaille in 1756, after his trip to the Cape of Good Hope, where he observed the southern stars and constellations. Lacaille originally named the constellation Fornax Chemica, the chemical furnace, after the small fuel heater used for chemical experiments. It was the English astronomer Francis Bailey who shortened the constellation’s name to Fornax at John Herchel’s suggestion in 1845.
According to traditional Chinese uranography, the modern constellation Fornax is located within the western quadrant of the sky, The White Tiger of the West (Xī Fāng Bái Hǔ). The name of the western constellation in modern Chinese is (tiān lú zuò), meaning ‘the heaven furnace constellation.’
[https://en.wikipedia.org/wiki/Fornax_%28Chinese_astronomy%29]
[http://www.peoplesguidetothecosmos.com/constellations/fornax.htm]
The three brightest stars- Alpha, Beta and Nu Fornacis- form a flattened triangle facing south.
Alpha Fornacis is the brightest star in the constellation Fornax. It is the only star brighter than magnitude 4.0 in the constellation. It has the proper names Dalim and Fornacis. This star was originally designated 12 Eridani.
The stellar classification of Alpha Fornacis is F8IV, where the luminosity class IV indicates this is a subgiant star that has just evolved off the main sequence. It has 33% more mass than the Sun and is an estimated 2.9 billion years old. Alpha Fornacis is a binary star and has a high proper motion. This system displays an excess of infrared emission, which may indicate the presence of circumstellar material such as a debris disk.
The secondary has been identified as a blue straggler, and has either accumulated material from, or merged with, a third star in the past. It is a strong source of X-rays and is 78% as massive as the Sun.
[https://en.wikipedia.org/wiki/Alpha_Fornacis]
Beta Fornacis is visible to the naked eye with an apparent visual magnitude of 4.46. It is located around 173 light years away from the Sun.
This is an evolved, G-type giant star with a stellar classification of G8 III. It is a red clump giant, which means it has undergone helium flash and is currently generating energy through the fusion of helium at its core. The star has an estimated 1.53 times the mass of the Sun and has expanded to 11 times the Sun’s radius. It is radiating over 55 times the solar luminosity from its outer atmosphere at an effective temperature of 4,820 K.
Beta Fornacis has a visual companion, CCDM J02491-3224B, which has an apparent visual magnitude of approximately 14.0. Located around three degrees to the southwest is the globular cluster NGC 1049.
[https://en.wikipedia.org/wiki/Beta_Fornacis]
Nu Fornacis is a class B9.5III (blue giant) star in the constellation Fornax. Its apparent magnitude is 4.69 and it is approximately 371 light years away. It is around 3.65 times as massive and 245 times as luminous as the Sun, with around 3.2 times its diameter. It is variable, with a period of 1.89 days- the same as its rotational period.
[https://en.wikipedia.org/wiki/Nu_Fornacis]
Artistic impression of HIP 13044 b
[https://fr.wikipedia.org/wiki/HIP_13044]
HIP 13044 is a red horizontal-branch star about 2,300 light years (700 pc) from Earth in the constellation Fornax. The star is part of the Helmi stream, a former dwarf galaxy that merged with the Milky Way between six and nine billion years ago. As a result, it circles the galactic center at a highly irregular orbit with respect to the galactic plane. HIP 13044 has an apparent magnitude of 9.94 and cannot be seen with the unaided eye.
This is 13044 is fairly evolved star fusing helium in its core, and has therefore already passed the red-giant phase of its evolution. Its surface temperature is about 6025 K and its radius is approximately 6.7 solar radii. HIP 13044’s mass is estimated to be 0.8 solar masses. Having a rotation period of 5-6 days, HIP 13044 is a fast-rotating star for its type. It is possible that this is because it has swallowed planets during its red-giant phase.
In 2010, it was announced that a giant planet in a 16.2-day orbit had been discovered by the radial velocity measurements. This would have had implications for planet formation in metal-poor systems and survival of planets being engulfed by expanded giant stars. Subsequent analysis of the data revealed problems with the detection. After applying the corrections, there is no evidence for a planet orbiting the star.
[https://en.wikipedia.org/wiki/HIP_13044]
HD 20782 is a 7th magnitude G-type main sequence star about 117 light-years away from Earth, in the constellation of Fornax. HD 20782 is a part of a wide binary system in which the other star is designated HD 20781, and both stars host planetary systems. Indeed, this is the first known case of a binary star system where there are planetary systems around both the primary and the secondary stars in the system. The companion star HD 20781 has a very large angular separation of 252 arcsec, corresponding to 9080 AU at the distance of HD 20782. It is estimated to be 7.1 (± 4) billion years old, with a mass close to that of our Sun. (Note that, despite the numbering, HD 20782 is the primary star of the system, and HD 20781 the secondary star.)
An extremely eccentric extrasolar planet was announced around HD 20782 in 2006. In 2009 this planet’s orbit was narrowed down, and it was found to have the highest eccentricity of all known exoplanets; this distinction has stood since 2012.
And in 2011 two also-eccentric (but less so) Neptune-mass planets were announced around the HD 20781.
[https://en.wikipedia.org/wiki/HD_20782]
Red dwarf star UDF 2457 as seen by the Hubble Ultra Deep Field (UDF)
UDF 2457 is the Hubble Ultra Deep Field (UDF) identifier for a red dwarf star calculated to be about 59,000 light-years (18 kiloparsecs) from Earth with a very dim apparent magnitude of 25.
The Milky Way galaxy is about 100,000 light-years in diameter, and the Sun is about 25,000 light-years from the galactic center. The small common star UDF 2457 may be one of the farthest known stars inside the main body of the Milky Way. Globular clusters (such as Messier 54 and NGC 2419) and stellar streams are located further out in the galactic halo.
[https://en.wikipedia.org/wiki/UDF_2457]
NGC 1049 by Hubble space telescope
NGC 1049 is a globular cluster located in the Local Group galaxy of Fornax Dwarf, visible in the constellation of Fornax. At a distance of 630,000 light years, it is visible in moderate sized telescopes, while the parent galaxy is nearly invisible.
[https://en.wikipedia.org/wiki/NGC_1049]
NGC 1360
NGC 1360, also known as the Robin’s Egg Nebula, is a planetary nebula in the constellation of Fornax. It was identified as a planetary nebula due to its strong radiation in the OIII (oxygen) bands. Reddish matter, believed to have been ejected from the original star before its final collapse, is visible in images.
[https://en.wikipedia.org/wiki/NGC_1360]
The Fornax Dwarf Spheroidal is an elliptical dwarf galaxy in the constellation. The galaxy is a satellite of the Milky Way and contains six globular clusters; the largest, NGC 1049, was discovered before the galaxy itself. The galaxy is also receding from the Milky Way at 53 km/s. It mostly contains population II stars:
Fornax dwarf galaxy
The Fornax dwarf galaxy is one of the Milky Way’s neighboring dwarf galaxies. New observations of four globular clusters- large balls of stars that orbit the centers of galaxies- found in Fornax show they are very similar to those found in our galaxy, the Milky Way. The finding is at odds with leading theories on how these clusters form — in these theories, globular clusters should be nestled among large quantities of old stars — and so the mystery of how these objects came to exist deepens.
[https://www.spacetelescope.org/images/heic1425h/]
The Fornax Cluster is a cluster of galaxies lying at a distance of 62 million light-years (19 megaparsecs). It is the second richest galaxy cluster within 100 million light-years, after the considerably larger Virgo Cluster. It lies primarily in the constellation Fornax, and may be associated with the nearby Eridanus Group. The Fornax Cluster is a valuable source of information about the evolution of such clusters, showing the effects of a merger of a subgroup with the main group, which in turn lends clues about the associated galactic superstructure.[5] At the centre of the cluster lies NGC 1399. Other cluster members include NGC 1316 (the group’s brightest galaxy), NGC 1365, NGC 1427A, and NGC 1404:
The Fornax Cluster of Galaxies
How do clusters of galaxies form and evolve? To help find out, astronomers continue to study the second closest cluster of galaxies to Earth: the Fornax cluster, named for the southern constellation toward which most of its galaxies can be found. Although almost 20 times more distant than our neighboring Andromeda galaxy, Fornax is only about 10 percent further that the better known and more populated Virgo cluster of galaxies. Fornax has a well-defined central region that contains many galaxies, but is still evolving. It has other galaxy groupings that appear distinct and have yet to merge. Seen here, almost every yellowish splotch on the image is an elliptical galaxy in the Fornax cluster. The picturesque barred spiral galaxy NGC 1365 visible on the lower right is also a prominent Fornax cluster member.
[http://apod.nasa.gov/apod/ap130111.html]
NGC 1399 is a large elliptical galaxy in the Southern constellation Fornax, the central galaxy in the Fornax cluster. It is a type-cD galaxy, with a bright center and a vast, diffuse envelope surrounding it. It is also rich in globular clusters, with a population of them that has been estimated to be between 5,700 and 6,500. A supermassive black hole with a mass of 500 million solar masses may be present in the center of this galaxy:
[https://en.wikipedia.org/wiki/NGC_1399]
NGC 1399: Massive Black Hole Implicated in Stellar Destruction
Evidence suggests that a white dwarf star has been torn apart by an intermediate-mass black hole. This object is found in a globular cluster, a very old, very crowded grouping of stars. If confirmed, this result would be the first time such a class of black hole was found in this setting. This system is found in the elliptical galaxy NGC 1399, which is in the Fornax cluster.
Evidence from NASA’s Chandra X-ray Observatory and the Magellan telescopes suggest a star has been torn apart by an intermediate-mass black hole in a globular cluster. In this image, X-rays from Chandra are shown in blue and are overlaid on an optical image from the Hubble Space Telescope. The Chandra observations show that this object is a so-called ultraluminous X-ray source (ULX). An unusual class of objects, ULXs emit more X-rays than any known stellar X-ray source, but less than the bright X-ray sources associated with supermassive black holes in the centers of galaxies. Their exact nature has remained a mystery, but one suggestion is that some ULXs are black holes with masses between about a hundred and a thousands times that of the Sun.
Data obtained in optical light with the Magellan I and II telescopes in Las Campanas, Chile, also provides intriguing information about this object, which is found in the elliptical galaxy NGC 1399 in the Fornax galaxy cluster. The spectrum reveals emission from oxygen and nitrogen but no hydrogen, a rare set of signals from within globular clusters. The physical conditions deduced from the spectra suggest that the gas is orbiting a black hole of at least 1,000 solar masses.
To explain these observations, researchers suggest that a white dwarf star strayed too close to an intermediate-mass black hole and was ripped apart by tidal forces. In this scenario the X-ray emission is produced by debris from the disrupted white dwarf star that is heated as it falls towards the black hole and the optical emission comes from debris further out that is illuminated by these X-rays.
Another interesting aspect of this object is that it is found within a globular cluster, a very old, very tight grouping of stars. Astronomers have long suspected globular clusters contained intermediate-mass black holes, but there has been no conclusive evidence of their existence there to date. If confirmed, this finding would represent the first such substantiation.
[http://chandra.harvard.edu/photo/2010/ngc1399/]
NGC 1316 (also known as Fornax A) is a lenticular radio galaxy about 60 million light-years away. The galaxy was built up through the merger of several smaller galaxies. These merger events may have fueled the central supermassive black hole, that has a mass estimated in 130-150 million of solar masses with gas, causing the galaxy to become a radio galaxy. The merger is estimated to have occurred ~3 billion years ago:
[https://en.wikipedia.org/wiki/NGC_1316]
NGC 1316: After Galaxies Collide
How did this strange-looking galaxy form? Astronomers turn detectives when trying to figure out the cause of unusual jumbles of stars, gas, and dust like NGC 1316. A preliminary inspection indicates that NGC 1316 is an enormous elliptical galaxy that includes dark dust lanes usually found in a spiral. The above image taken by the Hubble Space Telescope shows details, however, that help in reconstructing the history of this gigantic jumble. Close inspection finds fewer low mass globular clusters of stars toward NGC 1316's center. Such an effect is expected in galaxies that have undergone collisions or merging with other galaxies in the past few billion years. After such collisions, many star clusters would be destroyed in the dense galactic center. The dark knots and lanes of dust indicate that one or more of the devoured galaxies were spiral galaxies. NGC 1316 spans about 60,000 light years and lies about 75 million light years away toward the constellation of the Furnace.
[https://apod.nasa.gov/apod/ap050404.html]
NGC 1365, also known as the Great Barred Spiral Galaxy, is a barred spiral galaxy about 56 million light-years away. The core is an oval shape with an apparent size of about 50″ × 40″. The spiral arms extend in a wide curve north and south from the ends of the east-west bar and form an almost ring like Z-shaped halo. The central supermassive black hole in the active galactic nucleus, measured to be about 2 million solar masses in mass, is spinning at almost the speed of light. Supernovae 2012fr, 2001du, 1983V, and 1957C were observed in NGC 1365:
[https://en.wikipedia.org/wiki/NGC_1365]
NGC 1365: Majestic Spiral with Supernova
Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the chemical constellation Fornax, NGC 1365 is a dominant member of the well-studied Fornax galaxy cluster. This sharp color image shows intense star forming regions at the ends of the bar and along the spiral arms, and details of dust lanes cutting across the galaxy’s bright core. At the core lies a supermassive black hole. Astronomers think NGC 1365’s prominent bar plays a crucial role in the galaxy’s evolution, drawing gas and dust into a star-forming maelstrom and ultimately feeding material into the central black hole. Discovered on October 27, the position of a bright supernova is indicated in NGC 1365. Cataloged as SN2012fr, the type Ia supernova is the explosion of a white dwarf star.
[http://apod.nasa.gov/apod/ap121124.html]
NGC 1097 is a barred spiral galaxy about 45 million light-travel years away in the constellation Fornax. It is a severely interacting galaxy with obvious tidal debris and distortions caused by interaction with the companion galaxy NGC 1097A. Three supernovae (SN 1992bd, SN 1999eu, and SN 2003B) have been observed in NGC 1097 since 1992:
[https://en.wikipedia.org/wiki/NGC_1097]
Hubble Eyes a Wanderer Dancing the Dance of Stars and Space
The NASA/ESA Hubble Space Telescope provides us with a spectacular image of the bright star-forming ring that surrounds the heart of the barred spiral galaxy NGC 1097. In this image, the larger-scale structure of the galaxy is barely visible: its comparatively dim spiral arms, which surround its heart in a loose embrace, reach out beyond the edges of this frame.
This face-on galaxy, lying 45 million light-years away from Earth in the southern constellation of Fornax (The Furnace), is particularly attractive for astronomers. NGC 1097 is a Seyfert galaxy. Lurking at the very center of the galaxy, a supermassive black hole 100 million times the mass of our sun is gradually sucking in the matter around it. The area immediately around the black hole shines powerfully with radiation coming from the material falling in.
The distinctive ring around the black hole is bursting with new star formation due to an inflow of material toward the central bar of the galaxy. These star-forming regions are glowing brightly thanks to emission from clouds of ionized hydrogen. The ring is around 5000 light-years across, although the spiral arms of the galaxy extend tens of thousands of light-years beyond it.
NGC 1097 is also pretty exciting for supernova hunters. The galaxy experienced three supernovae (the violent deaths of high-mass stars) in the 11-year span between 1992 and 2003. This is definitely a galaxy worth checking on a regular basis.
However, what it is really exciting about NGC 1097 is that it is not wandering alone through space. It has two small galaxy companions, which dance ‘the dance of stars and the dance of space’ like the gracious dancer of the famous poem The Dancer by Khalil Gibran.
The satellite galaxies are NGC 1097A, an elliptical galaxy orbiting 42000 light-years from the center of NGC 1097 and a small dwarf galaxy named NGC 1097B. Both galaxies are located out beyond the frames of this image and they cannot be seen. Astronomers have indications that NGC 1097 and NGC 1097A have interacted in the past.
This picture was taken with Hubble’s Advanced Camera for Surveys using visual and infrared filters.
[https://www.nasa.gov/mission_pages/hubble/science/ngc1097.html]
UDFj-39546284 is the designation given to a stellar structure reported on January 27, 2011, as light from the oldest object detected through infrared observation within the Hubble Space Telescope. The object is located in the Fornax constellation. It was initially thought (November 2012) to be at redshift z~10 using Hubble and Spitzer telescope photometric data, including Hubble Extreme Deep Field (XDF). Subsequently it was reported to possibly be at a record-breaking redshift z = 11.9 using Hubble and Spitzer telescope data, including Hubble Ultra-Deep Field (HUDF). Recent analyses have suggested this source is more likely to be a low redshift interloper, with extreme emission lines in its spectrum producing the appearance of a very high redshift source:
[https://en.wikipedia.org/wiki/UDFj-39546284]
Most Distant Galaxy Candidate Ever Seen in Universe
The farthest and one of the very earliest galaxies ever seen in the universe appears as a faint red blob in this ultra-deep–field exposure taken with NASA’s Hubble Space Telescope. This is the deepest infrared image taken of the universe. Based on the object’s color, astronomers believe it is 13.2 billion light-years away.
The most distant objects in the universe appear extremely red because their light is stretched to longer, redder wavelengths by the expansion of the universe. This object is at an extremely faint magnitude of 29, which is 500 million times fainter that the faintest stars seen by the human eye.
The dim object is a compact galaxy of blue stars that existed 480 million years after the Big Bang, only four percent of the universe’s current age. It is tiny and considered a building block of today’s giant galaxies. Over one hundred such mini-galaxies would be needed to make up our Milky Way galaxy.
The Hubble Ultra Deep Field infrared exposures were taken in 2009 and 2010, and required a total of 111 orbits or 8 days of observing. The new Wide Field Camera 3 has the sharpness and near-infrared light sensitivity that matches the Advanced Camera for Surveys’ optical images and allows for such a faint object to be selected from the thousands of other galaxies in the incredibly deep images of the Hubble Ultra Deep Field.
[http://www.nasa.gov/mission_pages/hubble/science/ancient-object-gallery.html]
GOODS-S 29323: NASA Telescopes Find Clues For How Giant Black Holes Formed So Quickly
Evidence that some early supermassive black holes formed directly from the collapse of a gas cloud has been found. These results could represent a major step in the understanding of how the Universe’s first giant black holes formed. Two candidate black hole ‘seeds’ have been identified, possibly at less than one billion years after the Big Bang.
Astronomers combined data from Chandra, Hubble, and Spitzer to make this discovery. Using data from NASA’s three Great Observatories, scientists have found the best evidence to date of a mechanism that produced supermassive black holes in the early Universe. If confirmed, this result, described in our latest press release, could lead to new insight into how black holes were formed and grew billions of years ago.
This artist’s illustration depicts a possible ‘seed’ for the formation of a supermassive black hole, that is an object that contains millions or even billions of times the mass of the Sun. In the artist’s illustration, the gas cloud is shown as the wispy blue material, while the orange and red disk is showing material being funneled toward the growing black hole through its gravitational pull.
Researchers found evidence that two objects could have formed in this way, by directly collapsing into a black hole from a large cloud of gas. These two candidates for being ‘direct collapse black holes’ are so distant that they may have formed less than one billion years after the Big Bang.
The inset boxes show data from the Hubble Space Telescope (right) and Chandra X-ray Observatory (left) of one of the objects described above. The Hubble image shows the faint, distant galaxy at the center of the image and the Chandra image shows X-ray emission from material falling onto the black hole in the same galaxy.
The researchers used computer models of black hole seeds combined with a new method to select candidates for these objects from long-exposure images from Chandra, Hubble, and Spitzer (not shown in this graphic). By analyzing the combined light from the three telescopes, the team was able to search through thousands of objects to look for any that had properties that matched those predicted by their models.
Two candidates emerged that had the expected red color, seen by Hubble and Spitzer, as well as the X-ray profile predicted from Chandra. These objects were found in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey and the Great Observatories Origins Deep Survey-South surveys. The next steps will involve getting more data on these two intriguing objects as well as extending the analysis to other surveys to look for more direct collapse black hole candidates.
Distance Estimate: About 13.2 billion light years (z=9.73)
[http://chandra.harvard.edu/photo/2016/bhseeds/index.html]
[https://en.wikipedia.org/wiki/Fornax]
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