Dorado is a modern constellation in the southern hemisphere
it cannot be seen from Britain. Dorado
was one of twelve constellations named by Petrus Plancius on his star globe of
1597 and was based on information sent back by the Dutch navigators Pieter
Keyser and Frederick Houtman, when they voyaged to the southern hemisphere. The
constellation then appeared on a star map produced by Johan Bayer in 1603.
The term Dorado today is usually translated as the goldfish
which is how it appears on modern star maps. However, the name Dorado is
Spanish for mahi-mahi, or the dolphinfish. The mahi-mahi has an opalescent skin
that turns blue and gold as the fish dies. This may very well be the reason
Dorado is sometimes called the goldfish.
There are very few bright stars in Dorado, alpha which has no name is a magnitude 3.3 star and lies at a distance of 169 light years, and is an A class star hotter than the Sun.
Beta which again has no name but is s member of the
important Cepheid class of stars that astronomers use to determine how far away
the stars are. Beta varies between magnitude 3.5 and 4.1 and is 1,040 light
years away. The first of the cepheid variable stars was discovered by John
Goodricke the deaf astronomer in York in 1784.
By far the most interesting object in Dorado is the Large
Magellanic Cloud (LMC) a dwarf galaxy around 170,000 light years away. The
first recorded mention of the LMC was by the Persian astronomer `Abd al-Rahman
al-Sufi Shirazi, (later known in Europe as "Al Sufi"), in his Book of
Fixed Stars published around 964 CE. The next recorded observation was in
1503–4 by Amerigo Vespucci, Ferdinand Magellan sighted the LMC on his voyage in
1519, and his writings brought the LMC into common Western knowledge. The
galaxy now bears his name.
The LMC is the fourth-largest galaxy in the Local Group,
after the Andromeda Galaxy (M31), the Milky Way, and the Triangulum Galaxy
(M33). There is a Small Magellanic Cloud in the constellation of Tucana the
Toucan.
The LMC contains around 10 million stars. It can easily be
seen with the naked eye. There are lots of important star clusters and nebula
in the LMC including the Tarantula Nebula. This was first observed by Nicolas
Louis de Lacaille when he was observing at the Cape of Good Hope between 1751
and 1752.
The Tarantula Nebula is a massive star forming area within
the LMC if it was as close as the Orion Nebula another star forming area and
only 1,500 light years away it would be so bright that it would cast shadows.
One of thing to mention about the LMC was that in 1987 a
bright supernova appeared. The supernova was discovered by Ian Shelton and
Oscar Duhalde at the Las Campanas Observatory in Chile on February 24, 1987,
and within the same 24 hours independently by the amateur astronomer Albert
Jones in New Zealand. The supernova
reached a peak magnitude of about 3.0 in May before its brightness declined in
the following months.
Four days after the event was recorded, the progenitor star
was identified as Sanduleak −69° 202, a blue supergiant
It was only in 2019 over 30 years after the explosion that
astronomers found the central neutron star.
This star is known as SN1987A and as it is the closest
supernova to us since the invention of the telescopes it has been studied
extensively by astronomers and has allowed them to learn a great deal about how
a supernova works.
www.theramblingastronomer.co.uk
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