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Uncommon star 24 EP

HD 145556

RA 243.1815° · Dec -28.3217° · star

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Score breakdown

· 4 badges
24 pts · Uncommon
Uncommon 34 pts → Rare
  • Bright giant +12
  • Hot blue B-type star +6
  • Star +3
  • On the zodiac +3
Total score 24

10 more points to reach Rare.

Badges

  • Star · +3
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Bright giant · +12

Trivia

Hard to believe

  • True brightness. It pours out about 2.4 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 B4II/III — 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 8.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Scorpius.
  • 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 0.1) — 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
-11.1
bv
0.07
constellation
Sco
luminosity
2398832.919
mag
8.9
name
HD 145556
spect
B4II/III

About HD 145556

HD 145556 is an uncommon star. It sits in the constellation Sco, shines at apparent magnitude 8.9 and has spectral type B4II/III.

Its spectrum reads B4II/III — 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 145556 in the constellation Sco. At apparent magnitude 8.9, it is an easy target for binoculars.

Like any astronomical target, HD 145556 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 145556 is an uncommon star

HD 145556 scores 24 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 10 points would lift it into a rarer tier.

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