July 13

Leap Leap+1 Leap+2 Leap+3
1950 66Alpha GEM 66Alpha GEM 6CMI 62Rho GEM
69Upsilon GEM 6CMI
2000 6CMI 62Rho GEM 62Rho GEM

In a few cases you have a choice and you can consult the descriptions to see which one you like better.

Remember that a smaller magnitude number is a brighter star, if that is your preference.

Leap year in the 2000 era has no star, but Castor – 66Alpha Gem – is not too far into the 14th and would be a good choice.  Castor is a bright and well-known star and is close enough to be a reasonable choice for anyone on the 13th.

62Rho GEM
Birthday from Jack’s initial research: July 12
Magnitude: 4.2
Spectrum/Star type: Light Yellow
Distance in Light Years: 60
Diameter compared to Sun: 1.3
Luminosity compared to Sun: 6
Date best observed: Feb 26
Additional information: A Binary system with 1 or 2 other stars as well. Rho is just to the right of Castor.

Birthday from Jack’s initial research: July 12, a zodiac star!
Magnitude: 4.5
Spectrum/Star type: Orange Giant with White Dwarf companion
Distance in Light Years: 560
Diameter compared to Sun: 20
Luminosity compared to Sun: 85
Date best observed: Feb 27
Additional information: In the Zodiac despite being in “The Little Dog”. Nearby is
Procyon, the eighth brightest star, very close at 11 light years,
with a white dwarf companion. Procyon A 2x DIA & 7x LUM; The Dwarf
Star is just a bit bigger than the Earth! The sun passes this star on July 15, but it is not in the Zodiac.

66Alpha GEM  Castor
Birthday from Jack’s initial research: July 13
Magnitude: 1.6, 23rd brightest star.
Spectrum/Star type: Whitish
Distance in Light Years: 52
Diameter compared to Sun: System A has Two 2xDIA stars & system B has Two 1.5xDIA stars.
Luminosity compared to Sun: 49 total
Date best observed: Feb 28
Additional information: Six stars!!! The A and B systems (each doubles!) have a period of
445 yrs, and around all of them is a pair of Red Dwarfs that take at least 14,000 yrs to orbit the inner 4! The December Meteor Shower- “The Geminids” radiates nearby on the 13th or 14th-60/hr.
Castor is The Twin on the right, remember it has an “r” in its name! In a large telescope you can only see 2 stars. Castor was a horseman, and was mortal.

69Upsilon GEM
Birthday from Jack’s initial research: July 14
Magnitude: 4.1
Spectrum/Star type: Red Giant
Distance in Light Years: 240
Diameter compared to Sun: 30
Luminosity compared to Sun: 115
Date best observed: Feb 28
Additional information: A double star. Upsilon is dimmer than both Castor and Pollux, but in reality is much larger!

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