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Rare star 43 EP

47Rho Leo

RA 158.2028° · Dec 9.3066° · star

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Score breakdown

· 6 badges
43 pts · Rare
Rare 50 pts → Epic
  • Supergiant +18
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Blue-white star +5
  • Star +3
  • On the zodiac +3
Total score 43

7 more points to reach Epic.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Supergiant · +18
  • Blue-white star · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads B1Ib SB — 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 3.8 you can see it with your own eyes from a dark site, over in Leo.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around February — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out blue-white (B−V -0.1) — the hallmark of a surface far hotter than the Sun's.
  • 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 12450 K, against the Sun's 5778 K.

Properties

absmag
-16.16
bv
-0.148
constellation
Leo
luminosity
253512863.0498
mag
3.84
name
47Rho Leo
spect
B1Ib SB

About 47Rho Leo

47Rho Leo is a rare star. It sits in the constellation Leo, shines at apparent magnitude 3.84 and has spectral type B1Ib SB.

Its spectrum reads B1Ib SB — 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 47Rho Leo in the constellation Leo. At apparent magnitude 3.84, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 47Rho Leo 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 47Rho Leo is a rare star

47Rho Leo scores 43 points on Spacedle's rarity scale, which places it in the rare tier. Another 7 points would lift it into a rarer tier.

That score comes from 6 science badges — Star, Naked-eye visible, On the zodiac, Hot blue B-type star, Supergiant and Blue-white star — 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.