Dorado


Dorado is a constellation in the Southern Sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the mahi-mahi, which is known as dorado in Spanish, although it has also been depicted as a swordfish. Dorado contains most of the Large Magellanic Cloud, the remainder being in the constellation Mensa. The South Ecliptic pole also lies within this constellation.
Even though the name Dorado is not Latin but Spanish, astronomers give it the Latin genitive form Doradus when naming its stars; it is treated as a feminine proper name of Greek origin ending in -ō, which have a genitive ending -ūs.

History

Dorado was one of twelve constellations named by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. It appeared:
Dorado represents a dolphinfish; it has also been called the goldfish because Dorado are gold-colored.

Features

[Image:Constellation Dorado.jpg|thumb|left|256px|The constellation Dorado as it can be seen by the naked eye]

Stars

Lacaille gave 15 stars Bayer designations Alpha through Pi in 1756, but omitted Iota, Omicron, and Xi, and labelled two stars as Eta and Pi. Mu Doradus was removed from star catalogues because of its dimness.
Alpha Doradus is a blue-white star of magnitude 3.3, 176 light-years from Earth. It is the brightest star in Dorado. Beta Doradus is a notably bright Cepheid variable star. It is a yellow-tinged supergiant star that has a minimum magnitude of 4.1 and a maximum magnitude of 3.5. One thousand and forty light-years from Earth, Beta Doradus has a period of 9 days and 20 hours.
R Doradus is one of the many variable stars in Dorado. S Dor, 9.721 hypergiant in the Large Magellanic Cloud, is the prototype of S Doradus variable stars. The variable star R Doradus 5.73 has the largest-known apparent size of any star other than the Sun. WOH G64 is a binary system in the Large Magellanic Cloud that contains the largest known star with a well defined radius at 1,540 ± 77 solar radii. Gamma Doradus is the prototype of the Gamma Doradus variable stars.
Supernova 1987A was the closest supernova to occur since the invention of the telescope. SNR 0509-67.5 is the remnant of an unusually energetic Type Ia supernova from about 400 years ago.
HE 0437-5439 is a hypervelocity star escaping from the Milky Way/Magellanic Cloud system.
Dorado is also the location of the South Ecliptic pole, which lies near the fish's head. The pole was called "Polus Doradinalis" by Philipp von Zesen, aka Caesius.
In early 2020, the exoplanet TOI-700 d was discovered orbiting the star TOI-700 in Dorado. This is the first potentially Earth-like exoplanet to be discovered by the Transiting Exoplanet Survey Satellite.

Deep-sky objects

Because Dorado contains part of the Large Magellanic Cloud, it is rich in deep sky objects. The Large Magellanic Cloud, 25,000 light-years in diameter, is a satellite galaxy of the Milky Way Galaxy, located at a distance of 179,000 light-years. It has been deformed by its gravitational interactions with the larger Milky Way. In 1987, it became host to SN 1987A, the first supernova of 1987 and the closest since 1604. This 25,000-light-year-wide galaxy contains over 10,000 million stars. All coordinates given are for Epoch J2000.0.

Equivalents

In Chinese astronomy, the stars of Dorado are in two of Xu Guangqi's Southern Asterisms : the White Patches Attached and the Goldfish.

Namesakes