Antlia is a constellation in the southern sky. Its name means ‘pump,’ and it specifically represents an air pump. Located close to the stars forming the old constellation of the ship Argo Navis (contemporary constellations Carina, Puppis and Vela), Antlia is completely visible from latitudes south of 49 degrees north. Covering 238.9 square degrees and hence 0.579% of the sky, Antlia ranks 62nd of the 88 modern constellations by area. Hydra the sea snake runs along the length of its northern border, while Pyxis the compass, Vela the sails, and Centaurus the centaur line it to the west, south and east respectively. In the equatorial coordinate system, the right ascension coordinates of Antlia lie between 09h 26.5m and 11h 05.6m, while the declination coordinates are between −24.54° and −40.42°.
Johann Bode’s depiction of Antlia as a double-cylinder air pump
The French astronomer Nicolas Louis de Lacaille first described the constellation in French as ‘la Machine Pneumatique’ (the Pneumatic Pump) in 1751-52, commemorating the air pump invented by the French physicist Denis Papin. Lacaille Latinized the name to Antlia pneumatica on his 1763 chart. John Herschel proposed shrinking the name to one word, which was universally adopted.
There is no mythology attached to Antlia as Lacaille discontinued the tradition of giving names from mythology to constellations and instead chose names mostly from scientific instruments. Though Antlia was technically visible to Classical Greek astronomers, its stars were too faint to have been included in any ancient constellations. According to some, the most prominent stars that now comprise Antlia were once included within the ancient constellation Argo Navis, the Ship of the Argonauts, which due to its immense size was split into several smaller constellations by Lacaille in 1763. However, given the faintness and obscurity of its stars, most authorities do not believe that the ancient Greeks included Antlia as part of their classical depiction of Argo Navis.
Chinese astronomers were able to view what is modern Antlia from their latitudes, and incorporated its stars into two different constellations. Several stars in the southern part of Antlia were a portion of ‘Dong’ou,’ which represented an area in southern China. Furthermore, Epsilon, Eta, and Theta Antliae were incorporated into the celestial temple, which also contained stars from modern Pyxis.
[http://astropixels.com/constellations/charts/Ant.html]
Constellations of Antlia, Pyxis and Vela
[http://www.davidmalin.com/fujii/source/Ant.html]
The constellation’s two brightest stars- Alpha and Epsilon Antliae- shine with a reddish tinge. Alpha is an orange giant that is a suspected variable star, ranging between apparent magnitudes 4.22 and 4.29. It is located 370 ± 20 light-years away from Earth. Estimated to be shining with around 480 to 555 times the luminosity of the Sun, it is most likely an ageing star that is brightening and on its way to becoming a Mira variable star, having converted all its core fuel into carbon.
Located 710 ± 40 light-years from Earth, Epsilon Antliae is an evolved orange giant star that has swollen to have a diameter about 69 times that of the Sun, and a luminosity of around 1279 Suns. It is slightly variable.
Iota Antliae has an apparent visual magnitude of +4.60, making it a faint naked eye star. The distance to this star can be estimated as 190 light-years (58 parsecs). The spectrum of Iota Antliae matches a stellar classification of K1 III, indicating that this is an evolved star that is now in its giant phase. It is a core helium fusing star that is classified as a member of the red clump evolutionary branch.
[https://en.wikipedia.org/wiki/Iota_Antliae]
Theta Antliae is a binary star with a combined apparent visual magnitude of +4.78; the brighter component is magnitude +5.30 while the secondary is +6.18. It is located at a distance of around 340 light-years (100 parsecs) from Earth. The primary component of this system, θ Ant A, has a stellar classification of A8 Vm, indicating that it is an A-type main sequence star with enhanced metallic lines in its spectrum. The companion, θ Ant B, is a giant star with a classification of G7 III. The pair have an orbital period of 18.3 years, a significant eccentricity of 0.445, and they have an angular separation of 0.1 arcseconds.
[https://en.wikipedia.org/wiki/Theta_Antliae]
HD 93083 is an orange dwarf star of spectral type K3V that is smaller and cooler than the Sun. It has a planet that was discovered by the radial velocity method with the HARPS spectrograph in 2005. About as massive as Saturn, the planet orbits its star with a period of 143 days at a mean distance of 0.477 AU. WASP-66 is a sun-like star of spectral type F4V. A planet with 2.3 times the mass of Jupiter orbits it every 4 days, discovered by the transit method in 2012.
[http://memim.com/2mass-0939-2448.html]
True color image of the brown dwarf binary DENIS 1228-1547
This extremely dim brown dwarf is located at about 13.2 light-years (ly) away and so qualifies as one of the closest known. It lies at the southern edge of Constellation Antlia, the Air Pump- northeast of the Eight-Burst Planetary or Southern Ring Nebula (NGC 3132) and Phi Velorum. It is about 10,000 times too faint to be seen with the naked eye.
DENIS 1048-39 was discovered in 2000 by Xavier Delfosse and Thierry Forveille in images collected by the Deep Near-Infrared Survey (DENIS), which is mapping the southern sky with a one-meter telescope at the European Southern Observatory. The object’s unusual spectrum was confirmed by Eduardo L. Martin using the 10-meter Keck I telescope.
DENIS 1048-39 (also DENIS 1048-3956 or DENIS-P J104814.7-395606.1) is probably a young brown dwarf (spectral type M7.5) that is less than 20 million years old, rather than a very cool and dim, main sequence red dwarf (M8.5 V). It has a surface temperature of only 2,200° Kelvin and only about six to nine percent of Sol’s mass, near the 0.075 Solar mass limit for core thermonuclear fusion of hydrogen. The object radiates emits only 0.00015 percent as much visible light as Sol and so look dimmer than the full Moon from Earth if it replaced the Sun in the Solar System. Eduardo L. Martin analyzed the object with the Keck I Observatory but failed to detect lithium, a signature of all but the largest brown dwarfs. Hence, the object could be a very low-mass star (75-90 Jupiter masses) or a high-mass brown dwarf (60-75 Jupiter masses). The object spins at 27 kilometers per second (or over 16 miles per second), which would be very fast for a M-type dwarf star. In January 2003, two astronomers (Mary E. Putman and Adam J. Burgasser) reported that quiescent emission and two spectacular radio flares had been detected from the object.
When brown dwarfs were just a theoretical concern, astronomers differentiated those hypothetical objects from planets by how they were formed. If a substellar object was formed the way a star does, from a collapsing cloud of interstellar gas and dust, then it would be called a brown dwarf. If it was formed by gradually accumulating gas and dust inside a star’s circumstellar disk, however, it was called a planet. Once the first brown dwarf candidates were actually found, however, astronomers realized that it was actually quite difficult to definitely rule on the validity of competing hypotheses about how a substellar object was actually formed without having been there. This problem is particularly difficult to resolve in the case of stellar companions, objects that orbit a star- or two.
[http://www.solstation.com/stars/d1048-39.htm]
2MASS 0939-2448 (full designation is 2MASS J09393548-2448279) is a probable system of two nearby T-type brown dwarfs, located in constellation Antlia at 17.4 light-years from Earth. Model calculations suggest that the two brown dwarfs have an effective temperatures of about 500 and 700 K and masses of about 25 and 40 Jupiter masses; it is also possible that it is a pair of identical objects with temperatures of 600 K and 30 Jupiter masses.
From publication of the discovery in 2005 till at least 2008 2MASS 0939-2448 or its dimmer component was the dimmest brown dwarf known. Later dimmer objects, including (sub-)brown dwarfs and rogue planets of new spectral class Y, were discovered, using data from WISE and from other surveys. In 2011- 2014 the dimmest known of these objects was WISE 1828+2650, and from 2014 the dimmest one is WISE 0855−0714.
[https://en.wikipedia.org/wiki/2MASS_0939-2448]
Spiral Galaxy NGC 2997
This is a three-colour composite of the spiral galaxy NGC 2997 in the southern constellation Antlia (The Air Pump), obtained with the VLT UT1 and FORS1. It is based on three exposures in green, red and near-infrared bands, with the Moon above the horizon. The field measures 3.4 x 3.4 arcmin or, at the distance of the galaxy (about 55 million light-years), 55,000 x 55,000 light-years.
[https://www.eso.org/public/usa/images/eso9921a/]
Antlia contains many faint galaxies, the brightest of which is NGC 2997 at magnitude 10.6. It is a loose face-on spiral galaxy of type Sc. Though nondescript in most amateur telescopes, it presents bright clusters of young stars and many dark dust lanes in photographs.
Antlia Dwarf Galaxy Peppers the Sky with Stars
The myriad faint stars that comprise the Antlia Dwarf galaxy are more than four million light-years from Earth, but this NASA/ESA Hubble Space Telescope image offers such clarity that they could be mistaken for much closer stars in our own Milky Way. This very faint and sparsely populated small galaxy was only discovered in 1997.
This image was created from observations in visible and infrared light taken with the Wide Field Channel of Hubble’s Advanced Camera for Surveys. The field of view is approximately 3.2 by 1.5 arcminutes.
Although small, the Antlia Dwarf is a dynamic site featuring stars at many different stages of evolution, from young to old. The freshest stars are only found in the central regions where there is significant ongoing star formation. Older stars and globular clusters are found in the outer areas.
It is not entirely clear whether the Antlia Dwarf is a member of our galactic neighborhood, called the Local Group. It probably lies just beyond the normally accepted outer limits of the group. Although it is fairly isolated, some believe it has interacted with other star groups. Evidence comes from galaxy NGC 3109, close to the Antlia Dwarf (but not visible in this image). Both galaxies feature rifts of stars moving at comparable velocities; a telltale sign that they were gravitationally linked at some point in the past.
[http://www.nasa.gov/mission_pages/hubble/science/antlia-galaxy.html]
The Antlia Dwarf is a dwarf spheroidal/irregular galaxy which lies about 1.3 Mpc (4.3 million light-years) from Earth. It is the fourth and faintest member of the nearby Antlia Group of galaxies. The galaxy contains stars of all ages, contains significant amounts of gas, and has experienced recent star formation.
[https://en.wikipedia.org/wiki/Antlia_Dwarf]
The Antlia Cluster, also known as Abell S0636, is a cluster of galaxies located in the Hydra-Centaurus Supercluster. It is the third nearest to the Local Group after the Virgo Cluster and the Fornax Cluster. The cluster’s distance from earth is 40.5 Mpc (132.1 Mly) to 40.9 Mpc (133.4 Mly). Located in the southeastern corner of the constellation, it boasts the giant elliptical galaxies NGC 3268 and NGC 3258 as the main members of a southern and northern subgroup respectively, and contains around 234 galaxies in total.
[https://en.wikipedia.org/wiki/Antlia]
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