Pollux is the brightest star in the constellation of Gemini. It is an orange-hued evolved giant star, and also the closest giant star to the sun at a distance of only 34 light-years. Pollux along with Castor, are the two main guideposts for the asterism nicknamed the Twins. This might suggest that one or maybe both stars have altered in brightness since their designation around years ago. The name Pollux comes from a legend from both the Greek and Latin — Roman cultures.
The twins would help sailors in their time of need. They were the sons of Leda, the queen of Sparta. They had different fathers though, Castor had a mortal father and was thus mortal himself, while Pollux was the son of Zeus and was thus immortal. They also had a sister, the famous Helen of Troy. In a battle, Castor supposedly died and Pollux begged Zeus to let him die and be reunited with his brother. He decreed that Pollux would stay in Olympus for some periods of time while also visit his brother in the underworld.
Pollux formed around million years ago, most likely from a cloud of dust and gas. The gravity pulled together the swirling gas and dust to make the star that we see today as the brightest of the Gemini constellation. Though in the beginning, it is heavily implied that Pollux started off as a main-sequence star of spectral type A.
It eventually exhausted its supply of hydrogen and evolved into an orange giant. Measurements conducted by the Hipparcos astrometry satellite estimate that Pollux is around Being an evolved giant orange star, Pollux is considerably larger than the sun. It was suspected that Pollux might be a variable star. Pollux shines 48 times brighter than our sun — 48 solar luminosities, being the brightest star in its constellation.
Yang, M. Hartmann, M. Esposito, and D. Paulson confirmed the presence of a Jupiter-class planet "b" around Pollux, that was first detected in Hatzes et al, ; and Hatzes and Cochran, Assuming that Pollux has 1.
It moves around Pollux at an average distance of 1. The presence of the planet has been confirmed by continued monitoring Quirrenbach et al, Planetary candidate "b" is a Jupiter -class planet shown here with Europa.
Currently, the orbit of an Earth-like planet with liquid water around Pollux may be centered around 5. Astronomers would find it very difficult to detect an Earth-type planet in the water zone of this star using present methods. The following table includes all star systems known to be located within 10 light-years ly , plus more bright stars within 10 to 20 ly, of Pollux.
Constellation Gemini, the Twins, is the northernmost of the zodiacal constellations and among the brightest. In Greek mythology, Zeus the chief of the gods seduced Leda the wife of the King of Sparta, Tyndareos on her wedding night by changing himself into a swan. The twins, on the other hand, sailed with Jason in the quest for the Golden Fleece; during a storm, they helped save their ship ARGO from sinking, and so the constellation became much valued by sailors.
For more information about the stars and objects in this constellation and an illustration, go to Christine Kronberg's Gemini. For an illustration, see David Haworth's Gemini. For more information about stars including spectral and luminosity class codes, go to ChView's webpage on The Stars of the Milky Way.
The rest of the stars in the constellation represents their bodies, with Gemini easily located northeast of Orion , with other nearby constellations including Leo to its east, Taurus to its west, and Canis Minor to its south.
Since there are no other bright stars immediately around either Pollux or Castor when observing from low to mid-northern latitudes, the two stars are conspicuous and therefore easily spotted. However, since the two stars are relatively close to each other, it is easy to confuse one with the other, so to make sure the right star is observed bear in mind that Pollux appears as pale yellow, whereas Castor is white, with a pale blue tinge at times.
Pollux is also the brighter star of the pair, which makes its identification easier. It can then be seen throughout winter and spring in the northern hemisphere, with its best time for viewing during its midnight culmination around the 15th of January each year when the star is visible right through the night. Bear in mind also that Pollux is a circumpolar star from central Alaska, the northern reaches of Canada, and northward of central Scandinavia.
Having consumed all, or most of its hydrogen fuel, Pollux, has now evolved off of the main sequence into a giant star with an effective surface temperature of 4,K, which is typical of K-type, orange giant stars. Investigations are continuing.
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