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Rare star 34 EP

HD 103779

RA 179.2398° · Dec -63.2491° · star

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Score breakdown

· 5 badges
34 pts · Rare
Rare 50 pts → Epic
  • Bright giant +12
  • Under the Southern Cross +8
  • Hot blue B-type star +6
  • Blue-white star +5
  • Star +3
Total score 34

16 more points to reach Epic.

Badges

  • Star · +3
  • Under the Southern Cross · +8
  • Hot blue B-type star · +6
  • Bright giant · +12
  • Blue-white star · +5

Trivia

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 7.2 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Crux.
  • 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.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 10150 K, against the Sun's 5778 K.

Properties

absmag
-12.79
bv
-0.002
constellation
Cru
luminosity
11376272.8582
mag
7.21
name
HD 103779
spect
B0.5II

About HD 103779

HD 103779 is a rare star. It sits in the constellation Cru, shines at apparent magnitude 7.21 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 103779 in the constellation Cru. At apparent magnitude 7.21, it is an easy target for binoculars.

Like any astronomical target, HD 103779 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 103779 is a rare star

HD 103779 scores 34 points on Spacedle's rarity scale, which places it in the rare tier. Another 16 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, Under the Southern Cross, 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.