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Uncommon star 25 EP

40Zet Her

RA 250.3217° · Dec 31.6027° · 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 F9IV — 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 2.8 you can see it with your own eyes from a dark site, over in Hercules.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around May — that's when to go looking.

Could we get there?

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

Properties

absmag
2.66
binary
yes
bv
0.65
constellation
Her
dist ly
34.9502
luminosity
7.5162
mag
2.81
name
40Zet Her
spect
F9IV

About 40Zet Her

40Zet Her is an uncommon star. It lies about 35 light-years from Earth, sits in the constellation Her, shines at apparent magnitude 2.81 and has spectral type F9IV.

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 40Zet Her in the constellation Her. At apparent magnitude 2.81, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 40Zet Her 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 40Zet Her is an uncommon star

40Zet Her 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.