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Uncommon star 26 EP

HD 102475

RA 176.8258° · Dec -62.4362° · star

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Score breakdown

· 4 badges
26 pts · Uncommon
Uncommon 34 pts → Rare
  • Bright giant +12
  • Hot blue B-type star +6
  • Blue-white star +5
  • Star +3
Total score 26

8 more points to reach Rare.

Badges

  • Star · +3
  • Hot blue B-type star · +6
  • Bright giant · +12
  • Blue-white star · +5

Trivia

Hard to believe

  • True brightness. It pours out about 3.3 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 B0.5II — 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 bright giant, well on its way to the largest stars there are.

Find it in the sky

  • How to spot it. At magnitude 8.5 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 March — 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) — 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.

Properties

absmag
-11.47
bv
-0.035
constellation
Cen
luminosity
3372873.0866
mag
8.53
name
HD 102475
spect
B0.5II

About HD 102475

HD 102475 is an uncommon star. It sits in the constellation Cen, shines at apparent magnitude 8.53 and has spectral type B0.5II.

Its spectrum reads B0.5II — 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 102475 in the constellation Cen. At apparent magnitude 8.53, it is an easy target for binoculars.

Like any astronomical target, HD 102475 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 102475 is an uncommon star

HD 102475 scores 26 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 8 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, Hot blue B-type star, Bright giant 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.