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Rare star 38 EP

3 Gem

RA 92.4333° · Dec 23.1135° · star

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Score breakdown

· 5 badges
38 pts · Rare
Rare 50 pts → Epic
  • Supergiant +18
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Star +3
  • On the zodiac +3
Total score 38

12 more points to reach Epic.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Supergiant · +18

Trivia

What it actually is

  • Spectral class. Its spectrum reads B2.5Ib — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
  • Where it is in life. It is a supergiant, hundreds of times wider than the Sun.

Find it in the sky

  • How to spot it. At magnitude 5.8 you can see it with your own eyes from a dark site, over in Gemini.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around December — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out brilliant white (B−V 0.2) — hotter and whiter than the Sun, the colour of Sirius or Vega.
  • Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 8230 K, against the Sun's 5778 K.

Properties

absmag
-14.25
bv
0.192
constellation
Gem
luminosity
43651583.224
mag
5.75
name
3 Gem
spect
B2.5Ib

About 3 Gem

3 Gem is a rare star. It sits in the constellation Gem, shines at apparent magnitude 5.75 and has spectral type B2.5Ib.

Its spectrum reads B2.5Ib — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for 3 Gem in the constellation Gem. At apparent magnitude 5.75, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 3 Gem is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.

Why 3 Gem is a rare star

3 Gem scores 38 points on Spacedle's rarity scale, which places it in the rare tier. Another 12 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, Naked-eye visible, On the zodiac, Hot blue B-type star and Supergiant — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.