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Uncommon star 25 EP

Kap Tuc

RA 18.9406° · Dec -68.8759° · star

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Score breakdown

· 5 badges
25 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Binary star +6
  • Subgiant (leaving the main sequence) +5
  • Star +3
  • Yellow-white F-type star +3
Total score 25

9 more points to reach Rare.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • Binary star · +6
  • Yellow-white F-type star · +3
  • Subgiant (leaving the main sequence) · +5

Trivia

What makes it special

  • Not one star but two. It is a binary: two stars orbiting a shared centre of mass. More than half of all the 'stars' you can see are actually multiple systems.

What it actually is

  • Spectral class. Its spectrum reads F6IV — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • Where it is in life. It is a subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.

Sense of scale

  • In perspective. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 4.2 you can see it with your own eyes from a dark site, over in Tucana.
  • 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 October — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Properties

absmag
2.643
binary
yes
bv
0.48
constellation
Tuc
dist ly
68.3479
luminosity
7.6348
mag
4.25
name
Kap Tuc
spect
F6IV

About Kap Tuc

Kap Tuc is an uncommon star. It lies about 68.3 light-years from Earth, sits in the constellation Tuc, shines at apparent magnitude 4.25 and has spectral type F6IV.

It is a binary: two stars orbiting a shared centre of mass. More than half of all the 'stars' you can see are actually multiple systems.

How to see it

Look for Kap Tuc in the constellation Tuc. At apparent magnitude 4.25, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, Kap Tuc 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 Kap Tuc is an uncommon star

Kap Tuc scores 25 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 9 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, Naked-eye visible, Binary star, Yellow-white F-type star and Subgiant (leaving the main sequence) — 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.