POLLUX (BETA (β) GEMINORUM)
RED GIANT STAR

Right Ascension:
7h 45m 18s

Best Seen:
1/1 - 6/1

Declination:
28º 01' 34"

Magnitude:
1.16

Computer File:
pollux

Constellation:
Gemini

Actual

Compared to Sun

Distance

34 l.y.

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Actual Brightness

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29

Surface Temperature

8,400 ºF

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Diameter

~ 8.6 million miles

~ 10

Mass

--

--

Surface Gravity

--

--

Surface Composition (by mass)

74% hydrogen 24% helium 2% everything else

same

Spectral Type

K0 III

G2 V

Density (gram/cubic cm)

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WHAT TO LOOK FOR THROUGH THE TELESCOPE:

  1. Recommended eyepiece: 24mm or 40 mm.

  2. When people look through the telescope a bright reddish point of light should be seen.

POLLUX INFORMATION:

  1. Pollux is the 12th brightest star in the Northern Hemisphere’s night sky (17th brightest if including the Southern Hemisphere’s bright stars).

  2. It is actually brighter than Castor, known as alpha Geminorum. This breaks from the tradition of using “alpha” to refer to the brightest star in the constellation.

  3. In June, 2006, astronomers confirmed the presence of a Jupiter-class planet around Pollux, that was first detected in 1993. It is Beta Geminorum b.

a. The planet has a minimum mass of 2.3 Jupiter-masses and maybe up to 2.9 masses. b. It moves around Pollux at an average distance of 1.64 AUs (11 percent farther than Mars is from the Sun), and takes 1.6 years to orbit.

  1. In Greek mythology, Castor and Gemini were twin warriors. Pollux was fathered by Zeus and was therefore divine, while Castor was mortal. They were placed in the sky to allow them to be together for all time.

Item
Updated Notes

Coordinates 01-07-2003
tweaked a bit, now OK with Scott’s The Flamsteed Collection and SIMBAD

Magnitude
01-07-2003
OK with Flamsteed and SIMBAD

Distance
01-07-2003
OK with Flamsteed and SIMBAD

Actual Brightness
01-07-2003
previously said 35 – but with Flamsteed more like 29

Surface Temperature 01-07-2003
with range given in Flamsteed for K stars: 3500-4900 K... pollux is K0, so upper end of range

Diameter
01-07-2003
previously 3.6 million miles / 4-5 times Sun – but this says can calculate 11 times sun, measure angular diameter and 8.3 times sun http://www.astro.uiuc.edu/~kaler/sow/pollux.html

Mass

Surface Gravity

Surface Composition 01-07-2003
OK for all stars

Spectral Type
01-07-2003
OK with Flamsteed, SIMBAD

Density

Other Information
01-07-2003
brightness rank from Hipparcos page Other from http://www.astro.uiuc.edu/~kaler/sow/pollux.html

Planet info 9-11-2006
http://www.solstation.com/stars2/pollux.htm http://www.astro.uiuc.edu/~kaler/sow/pollux.html