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Uncommon star 27 EP

HD 112842

RA 195.1314° · Dec -60.3754° · star

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Score breakdown

· 3 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Supergiant +18
  • Hot blue B-type star +6
  • Star +3
Total score 27

7 more points to reach Rare.

Badges

  • Star · +3
  • Hot blue B-type star · +6
  • Supergiant · +18

Trivia

What it actually is

  • Spectral class. Its spectrum reads B3Ib — 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 supergiant, hundreds of times wider than the Sun.

Find it in the sky

  • How to spot it. At magnitude 7.1 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 0.2) — 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 8380 K, against the Sun's 5778 K.

Properties

absmag
-12.93
bv
0.173
constellation
Cen
luminosity
12941958.4145
mag
7.07
name
HD 112842
spect
B3Ib

About HD 112842

HD 112842 is an uncommon star. It sits in the constellation Cen, shines at apparent magnitude 7.07 and has spectral type B3Ib.

Its spectrum reads B3Ib — 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 112842 in the constellation Cen. At apparent magnitude 7.07, it is an easy target for binoculars.

Like any astronomical target, HD 112842 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 112842 is an uncommon star

HD 112842 scores 27 points on Spacedle's rarity scale, which places it in the uncommon 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 Supergiant — 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.