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Common star 15 EP

HD 122537

RA 211.0643° · Dec -57.4098° · star

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Score breakdown

· 3 badges
15 pts · Common
Common 22 pts → Uncommon
  • Hot blue B-type star +6
  • Giant star +6
  • Star +3
Total score 15

7 more points to reach Uncommon.

Badges

  • Star · +3
  • Hot blue B-type star · +6
  • Giant star · +6

Trivia

Hard to believe

  • True brightness. It pours out about 1.5 million times as much light as the Sun. It only looks ordinary because it is so far away.

What it actually is

  • Spectral class. Its spectrum reads B9III/IV — 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 giant. It has already exhausted its core hydrogen and swollen up enormously in response.

Find it in the sky

  • How to spot it. At magnitude 9.4 you'll want a small backyard telescope, over in Centaurus.
  • 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 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.

Properties

absmag
-10.62
bv
0.099
constellation
Cen
luminosity
1541700.4529
mag
9.38
name
HD 122537
spect
B9III/IV

About HD 122537

HD 122537 is a common star. It sits in the constellation Cen, shines at apparent magnitude 9.38 and has spectral type B9III/IV.

Its spectrum reads B9III/IV — 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 HD 122537 in the constellation Cen. At apparent magnitude 9.38, a small backyard telescope will bring it into view.

Like any astronomical target, HD 122537 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 122537 is a common star

HD 122537 scores 15 points on Spacedle's rarity scale, which places it in the common tier. Another 7 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Hot blue B-type star and Giant 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.