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Common star 17 EP

HD 139840

RA 235.1066° · Dec -0.9124° · star

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Score breakdown

· 3 badges
17 pts · Common
Common 22 pts → Uncommon
  • Sun-like G-type star +8
  • Giant star +6
  • Star +3
Total score 17

5 more points to reach Uncommon.

Badges

  • Star · +3
  • Sun-like G-type star · +8
  • Giant star · +6

Trivia

What it actually is

  • Spectral class. Its spectrum reads G8III — a G-type star: the very same spectral class as our own Sun.
  • Where it is in life. It is a giant. It has already exhausted its core hydrogen and swollen up enormously in response.

Sense of scale

  • In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 8.1 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Serpens.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • 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.

Getting there

  • Aboard Voyager 1. ≈ 11.3 million years at Voyager 1's speed (17 km/s).

Properties

absmag
1.595
bv
1.12
constellation
Ser
dist ly
643.3059
luminosity
20.0447
mag
8.07
name
HD 139840
spect
G8III

Nearby objects

About HD 139840

HD 139840 is a common star. It lies about 643.3 light-years from Earth, sits in the constellation Ser, shines at apparent magnitude 8.07 and has spectral type G8III.

Its spectrum reads G8III — a G-type star: the very same spectral class as our own Sun.

How to see it

Look for HD 139840 in the constellation Ser. At apparent magnitude 8.07, it is an easy target for binoculars.

Like any astronomical target, HD 139840 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 139840 is a common star

HD 139840 scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Sun-like G-type star and Giant 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.