Features Gemini (constellation)

1 features

1.1 stars
1.2 deep-sky objects
1.3 meteor showers

features
stars

the constellation contains 85 stars visible observation on earth without telescope.

the brightest star in gemini pollux, , second brightest castor. castor s bayer designation alpha attributable mistake johann bayer, gave eponymous designations in 1603.

α gem (castor) sextuple star system 52 light-years earth, appears magnitude 1.6 blue-white star unaided eye. 2 spectroscopic binaries visible @ magnitudes 1.9 , 3.0 period of 470 years. wide-set red dwarf star part of system; star algol-type eclipsing binary star period of 19.5 hours; minimum magnitude 9.8 , maximum magnitude 9.3.

β gem (pollux) orange-hued giant star of magnitude 1.2, 34 light-years earth. pollux has extrasolar planet revolving around it, 2 other stars in gemini, hd 50554, , hd 59686.

γ gem (alhena) blue-white hued star of magnitude 1.9, 105 light-years earth. δ gem (wasat) long-period binary star 59 light-years earth. primary white star of magnitude 3.5, , secondary orange dwarf star of magnitude 8.2. period on 1000 years; divisible in medium amateur telescopes.

ε gem (mebsuta), double star, includes primary yellow supergiant of magnitude 3.1, 900 light-years earth. optical companion, of magnitude 9.2, visible in binoculars , small telescopes.

ζ gem (mekbuda) double star, primary cepheid variable star period of 10.2 days; minimum magnitude 4.2 , maximum magnitude 3.6. yellow supergiant, 1200 light-years earth, radius 60 times solar, making approximately 220,000 times size of sun. companion, magnitude 7.6 star, visible in binoculars , small amateur telescopes.

η gem (propus) binary star variable component. 350 light-years away, has period of 500 years , divisible in large amateur telescopes. primary semi-regular red giant period of 233 days; minimum magnitude 3.9 , maximum magnitude 3.1. secondary of magnitude 6.

κ gem binary star 143 light-years earth. primary yellow giant of magnitude 3.6; secondary of magnitude 8. 2 divisible in larger amateur instruments because of discrepancy in brightness.

ν gem double star divisible in binoculars , small amateur telescopes. primary blue giant of magnitude 4.1, 500 light-years earth, , secondary of magnitude 8. 38 gem, binary star, divisible in small amateur telescopes, 91 light-years earth. primary white star of magnitude 4.8 , secondary yellow star of magnitude 7.8.

u gem dwarf nova type cataclysmic variable discovered j.r. hind in 1855.

mu gem bayer designation star in northern constellation of gemini. has traditional name tejat posterior, means foot, because foot of castor, 1 of gemini twins.

deep-sky objects

the medusa nebula

since sky area of gemini directed away milky way, there comparatively few deep-sky objects of note.

m35 (ngc 2168) large, elongated open cluster of magnitude 5, discovered in year 1745 swiss astronomer philippe loys de chéseaux. has area of approximately 0.2 square degrees, same size full moon. high magnitude means m35 visible unaided eye under dark skies; under brighter skies discernible in binoculars. 200 stars of m35 arranged in chains curve throughout cluster; 2800 light-years earth. open cluster in gemini ngc 2158. visible in large amateur telescopes , rich, more 12,000 light-years earth.

the eskimo nebula or clown face nebula (ngc 2392) planetary nebula overall magnitude of 9.2, located 4000 light-years earth. in small amateur telescope, 10th magnitude central star visible, along blue-green elliptical disk. named resemblance head of person wearing parka.

the medusa nebula planetary nebula, 1,500 light years distant. geminga neutron star approximately 550 light years earth. other objects include ngc 2129, ngc 2158, ngc 2266, ngc 2331, ngc 2355, , ngc 2395.

meteor showers

the geminids bright meteor shower peaks on december 13–14. has maximum rate of approximately 100 meteors per hour, making 1 of richest meteor showers. epsilon geminids peak between october 18 , october 29 , have been confirmed. overlap orionids, make epsilon geminids difficult detect visually. epsilon geminid meteors have higher velocity orionids.