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Beta (β) Geminorum
Pollux
Red Giant Star
| Right Ascension | 7h 45m 18s | Best Seen | 1/1 - 6/1 |
| Declination | 28° 01' 34" | Magnitude | 1.16 |
| Constellation | Gemini | ||
| Actual | Compared to Sun | |
| Distance | ~34 ly | -- |
| Actual Brightness | -- | 29 |
| Surface Temperature | ~8,400 °F | -- |
| 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) | -- | -- |
What To Look For Through The Telescope
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Recommended eyepiece: 24mm or 40 mm.
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When people look through the telescope a bright reddish point of light should be seen.
Pollux Information:
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Pollux is the 12th brightest star in the Northern Hemisphere’s night sky (17th brightest if including the Southern Hemisphere’s bright stars).
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It is actually brighter than Castor, known as alpha Geminorum. Johannes Bayer designated Castor as Alpha Geminorum in the 17th century, suggesting that one of these stars changed in luminosity in the past four centuries.
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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.
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In Greek mythology, Castor and Pollux 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.
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References
| Item | Updated | Notes |
| Coordinates | 2003-01-07 | tweaked a bit, now OK with Scott’s The Flamsteed Collection and SIMBAD |
| Magnitude | 2003-01-07 | OK with Flamsteed and SIMBAD |
| Distance | 2003-01-07 | OK with Flamsteed and SIMBAD |
| Actual Brightness | 2003-01-07 | previously said 35 – but with Flamsteed more like 29 |
| Surface Temperature | 2003-01-07 | with range given in Flamsteed for K stars: 3500-4900 K... pollux is K0, so upper end of range |
| Diameter | 2003-01-07 | 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 | 2003-01-07 | OK for all stars |
| Spectral Type | 2003-01-07 | OK with Flamsteed, SIMBAD |
| Density | -- | |
| Other Information | 2003-01-07 | brightness rank from Hipparcos page Other from http://www.astro.uiuc.edu/~kaler/sow/pollux.html Planet info - 2006-09-11 - http://www.solstation.com/stars2/pollux.htm http://www.astro.uiuc.edu/~kaler/sow/pollux.html Regarding Bayer designation - http://www.solstation.com/stars2/pollux.htm |