What is the constellation Draco?
The Dragon (Draco), is a constellation in the northern hemisphere. It is one of the 88 modern constellations, and one of the 48 described by Ptolemy.
Main Stars Draco
Thuban (α Draconis)
The star α Draconis (Thuban) was at the North Pole around 2700 BC, during the time of the ancient Egyptians. Due to the effect of precession, it will be at the North Pole again in 21,000 AD.
Although it appears in the Bayer Thuban catalog as α Draconis, it is not the brightest star in the constellation. At magnitude 3.65, it is one magnitude fainter than the brightest star: Etamin (γ Draconis), magnitude 2.23.
Thuban It is a hot giant star (9800 K, 300 times more luminous than the Sun and at a distance of 300 light-years. It is also a double star, the companion – invisible from Earth – returns in 51 days.
γ Draconis
γ Draconis It is the brightest star in the Draco constellation. Its name derives from an Arabic word that means Serpent.
γ Draconis is an orange giant, 50 times larger than the Sun, 600 times more luminous. It is located 150 light years away, is moving in our direction and will pass less than 30 light years from our system in 1.5 million years.
It was by trying to measure the parallax of γ Draconis that James Bradley discovered the aberration of light around the year 1725.
Other stars
β Draconis It is a supergiant, 40 times larger than the Sun. Located about 400 light years away, its absolute magnitude is -2.43, with the brightness of 800 suns. Its apparent magnitude is 2.79. It has a partner located at 450 ua.
Nodus Primus (ζ Dra), is a star of apparent magnitude 3.17. Its absolute magnitude of -1.92 corresponds to a brightness 500 times that of the Sun. Distance: 300 light years.
ι Draforty times more luminous than the Sun (absolute magnitude 0.81), is seen, 100 light-years away, with magnitude 3.29.
η Draconis It is a star of apparent magnitude 2.73. Its absolute magnitude is 0.58. It shines like 50 suns and is located 88 light years away.
In Draco There are many interesting double stars. Kuma (ν Draconis) is formed by two components of magnitude 4.9, separated by 62 arcseconds. They can be separated with binoculars.
R Draconis and T Draconis They are variable stars of the Mira type. The range of R is between magnitudes 6.7 and 13 with a period of 245.5 days, and T between magnitude 7.2 and 13.5 with a period of 421.2 days.
There are also two triple systems: 16-17 Draconis and 39 Draconis.
Notable Deep Sky Objects Draco
One of the deep sky objects Draco is the Cat’s Eye Nebula (NGC 6543), a planetary nebula that looks like a blue disk. Among the faint Draco galaxies, one can call the Lenticular Galaxy NGC 5866, which is sometimes considered to be the Messier 102 object.
Draco mythology
Due to his resemblance to a dragon there is more than one myth surrounding Draco. In the first legend, Draco represented the dragon killed by Cadmus before founding the city of Boeotia. In the second legend, he represents the dragon that guarded the Golden Fleece, and that was killed by Jason.
In another myth, it represents Ladon, the dragon who guarded the apples of the Hesperides, one of the Twelve Labors of Hercules. Due to his position and being close to the constellations of the Zodiac sign of Libra: Ursa Major, Ursa Minor, and Boötes, gave rise to the myth.