Pollux / Beta Geminorum Star Facts (Type, Distance, Magnitude, Age, Mass, Colour, Location, Exoplanets and more)

Facts

Pollux, also known as Beta Geminorum is a giant star located in the constellation of Gemini, The Twins. Pollux is a major star and forms part of the constellation. Pollux is the traditional/proper name for the star, whilst Beta Geminorum is the Bayer Designation for the star. A list of additional names and identifications is in the facts list at the bottom of the page.

Based on the spectral type (K0IIIvar), Pollux colour is orange to red, these are stars that are cooler than our own star.

Pollux temperature in is the range of between 3,700 and 5,200 Kelvin. Pollux effective temperature is 4,586 Kelvin which is cooler than the Sun's effective temperature which is 5,777 Kelvin. The uncertainty range for the effective temperature is between -4529 and +4643.

Pollux is the brightest star in Gemini and the 17th in the night sky based on the Hipparcos 2007 apparent magnitude. Based on a parallax of 96.54, Pollux distance from Earth can be calculated at being 33.79 light-years away or 10.34 parsecs.

Pollux is a naked-eye star, so you don't need a telescope or binoculars when you look up on a clear night. The lower the magnitude, the easier it will be to see it.

Pollux is the star that is the head of the left twin in the Gemini constellation. The other head is the star, Castor. It is one of a few stars with common names with an Extrasolar Planet orbiting around it. The reason for this is most other stars with Common names are giants and are at the ends of their lives, such as Betelgeuse in the constellation of Orion.

Although Castor is a multiple-star system with six stars, Pollux is a solitary star with a planet to keep it company.

Dying Star

Pollux is no longer a Main Sequence Star, having used up its hydrogen and now fusing helium to heavier chemicals such as Oxygen and Carbon. Sky and Telescope It is growing as the outward pressure is overcoming the inward pressure of Gravity becoming a Red Giant Star then losing its mass in solar winds.

The phase in which the star loses its mass through solar winds is the Planetary Nebula phase. All that will be left will be a White Dwarf Star like Sirius B, our nearest White Dwarf star. Our star, The Sun, will begin the same process about 1 billion years from now and will take an estimated four billion years until it reaches the Planetary Nebula phase.

Although it is growing, having used up its hydrogen supplies, its solar system can still host a planet orbiting it. The planet is believed to be a gas giant that is about 2.3 times the size of Jupiter and orbits around Pollux for about 590 days. ref: Space.

Pollux Legend

Pollux may be the brightest star in the constellation, but it only has the Beta designation. The incorrect assignment is probably due to an error in identifying which star was brighter. The twin star is Castor, and they are not close in the distance. They represent the heads of Legendary Characters

The stars Castor and Pollux represent the brothers who journeyed with Jason and the Argonauts to get the golden fleece of Aries.

Location

The location of the Pollux in the night sky is determined by the right ascension (R.A.) and declination (Dec.). These are equivalent to the Longitude and Latitude on Earth. The Right Ascension (Longitude) is expressed in time (hh:mm:ss) and is how far the star is along Earth's celestial equator. If the R.A. is positive, then it's eastwards and vice versa.

The Declination (Latitude) is how far north or south the object is compared to the celestial equator and is expressed in degrees. If the value is positive, it is north of the celestial equator. For Pollux, the location is 07h 45m 19.36 and +28° 01' 34.7 .

Based on the location of Gemini, Pollux can be located in the northern hemisphere of the celestial sky. The celestial hemisphere is equivalent to the hemispheres on Earth. Pollux is on the Ecliptic. The Ecliptic is the path that the Earth takes as it orbits the Sun. As the Earth is titled, we therefore have Celestial and Ecliptic hemispheres and they can be different for a star.

Physical Properties

Pollux Luminosity

Luminosity is the amount of energy a star pumps out relative to the amount that our star, the Sun, gives out. Our star, the Sun's value is 1. Pollux luminosity figure of 44.4 is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012. The star generates more energy than our star.

Pollux Size (Radius)

Pollux radius has been calculated as being 9.06 times bigger than the Sun. The Sun's radius is 695,800km, therefore, the Pollux radius is an estimated 6,303,948.km. If you need the star's diameter, you just need to multiply the radius by 2. The error range for the radius is between 9.03000 and 9.09000.

Magnitude (Apparent / Absolute / Visible)

A number represents a star’s magnitude, whether apparent/visual or absolute. The smaller the number, the brighter the star is. The Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Pollux apparent magnitude is 1.16, which is a measure of the star's brightness as seen from Earth. Apparent Magnitude is also known as Visual Magnitude.

If you use the 1997 parallax value, Pollux' absolute magnitude is 1.09. If you use the 2007 parallax value, Pollux' absolute magnitude is 1.08. Absolute Magnitude is the star's apparent magnitude from 10 parsecs or 32.6 light-years. The magnitude assumes nothing is between the object and the viewer, such as dust clouds. To compare different stars' actual brightness, you would best use Absolute rather than Apparent Magnitude.

Pollux is visible from Earth without needing binoculars or a telescope. The lower the Apparent Magnitude of a star or other object is, the easier it is to see in the night sky. An object with a magnitude greater than 6.5 cannot be seen without a telescope or other device.