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Uncommon star 29 EP

HD 123590

RA 212.6832° · Dec -62.4790° · star

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Score breakdown

· 2 badges
29 pts · Uncommon
Uncommon 34 pts → Rare
  • Blazing O-type star +26
  • Star +3
Total score 29

5 more points to reach Rare.

Badges

  • Star · +3
  • Blazing O-type star · +26

Trivia

What it actually is

  • Spectral class. Its spectrum reads O7/O8 — 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 7.6 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Centaurus.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around April — 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 0.1) — 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 8910 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HD number is from the Henry Draper Catalogue, in which Annie Jump Cannon personally classified the spectra of nearly 400,000 stars — still the largest such feat by one person.

Properties

absmag
-12.37
bv
0.112
constellation
Cen
luminosity
7726805.851
mag
7.63
name
HD 123590
spect
O7/O8

Nearby objects

About HD 123590

HD 123590 is an uncommon star. It sits in the constellation Cen, shines at apparent magnitude 7.63 and has spectral type O7/O8.

Its spectrum reads O7/O8 — 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 HD 123590 in the constellation Cen. At apparent magnitude 7.63, it is an easy target for binoculars.

Like any astronomical target, HD 123590 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 HD 123590 is an uncommon star

HD 123590 scores 29 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 5 points would lift it into a rarer tier.

That score comes from 2 science badges — Star 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.