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Rare star 37 EP

HR 6187

RA 250.3351° · Dec -48.7630° · star

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Score breakdown

· 3 badges
37 pts · Rare
Rare 50 pts → Epic
  • Blazing O-type star +26
  • Naked-eye visible +8
  • Star +3
Total score 37

13 more points to reach Epic.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • Blazing O-type star · +26

Trivia

What it actually is

  • Spectral class. Its spectrum reads O5 — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.

Find it in the sky

  • How to spot it. At magnitude 5.6 you can see it with your own eyes from a dark site, over in Ara.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around May — 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 8410 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HR number is from the Bright Star Catalogue — roughly 9,100 stars, essentially everything the unaided eye can see.

Properties

absmag
-14.43
bv
0.169
constellation
Ara
luminosity
51522864.4582
mag
5.57
name
HR 6187
spect
O5

About HR 6187

HR 6187 is a rare star. It sits in the constellation Ara, shines at apparent magnitude 5.57 and has spectral type O5.

Its spectrum reads O5 — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.

How to see it

Look for HR 6187 in the constellation Ara. At apparent magnitude 5.57, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HR 6187 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 HR 6187 is a rare star

HR 6187 scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Naked-eye visible and Blazing O-type 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.