Antlia

Lore & Background

The French astronomer Nicolas-Louis de Lacaille first described the constellation in French as la Machine Pneumatique in 1751–52, commemorating the air pump invented by the French physicist Denis Papin. De Lacaille had observed and catalogued almost 10,000 southern stars during a two-year stay at the Cape of Good Hope, devising fourteen new constellations in uncharted regions of the Southern Celestial Hemisphere not visible from Europe. He named all but one in honour of instruments that symbolised the Age of Enlightenment. Lacaille depicted Antlia as a single-cylinder vacuum pump used in Papin's initial experiments, while German astronomer Johann Bode chose the more advanced double-cylinder version. Lacaille Latinised the name to Antlia pneumatica on his 1763 chart. English astronomer John Herschel proposed shrinking the name to one word in 1844, noting that Lacaille himself had abbreviated his constellations thus on occasion. This was universally adopted. The International Astronomical Union adopted it as one of the 88 modern constellations in 1922.

Although visible to the Ancient Greeks, Antlia's stars were too faint to have been commonly recognised as a figurative object, or part of one, in ancient asterisms. The stars that now comprise Antlia are in a zone of the sky associated with the asterism/old constellation Argo Navis, the ship of the Argonauts, in its latter centuries. Due to its immense size, Argo Navis was split into hull, poop deck and sails by Lacaille in 1763. Ridpath reports that due to their faintness, the stars of Antlia did not make up part of the classical depiction of Argo Navis.

In non-Western astronomy, 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.

Reader's Guide

Antlia's significance lies in its representation of Enlightenment-era scientific progress, commemorating Denis Papin's air pump. The constellation was established by Nicolas-Louis de Lacaille during his two-year stay at the Cape of Good Hope, where he catalogued almost 10,000 southern stars and devised fourteen new constellations, all but one named after instruments. The constellation's history reflects a shift from a two-word Latin name to a single-word name, a change proposed by John Herschel in 1844 and universally adopted. Its stars, though faint, include notable objects such as the eclipsing binary S Antliae, which will one day merge to form a single star, and two star systems with known exoplanets: HD 93083 and WASP-66. The constellation also contains the spiral galaxy NGC 2997 and the Antlia Dwarf Galaxy. Its boundaries were set by Belgian astronomer Eugène Delporte in 1930, and it covers 238.9 square degrees, ranking 62nd among the 88 modern constellations. The constellation is completely visible from latitudes south of 49 degrees north.

Did You Know?

• Antlia's name means 'pump' in Latin and Greek, representing an air pump.
• The constellation was originally called Antlia Pneumatica by Nicolas-Louis de Lacaille.
• S Antliae is an eclipsing binary star system whose stars are so close they will one day merge to form a single star.