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Uncommon star 30 EP

HD 181039

RA 290.1475° · Dec -39.9889° · star

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Score breakdown

· 6 badges
30 pts · Uncommon
Uncommon 34 pts → Rare
  • Toward the galactic centre +8
  • Distant (over 1,000 light-years) +6
  • White A-type star +5
  • Subgiant (leaving the main sequence) +5
  • Star +3
  • On the zodiac +3
Total score 30

4 more points to reach Rare.

Badges

  • Star · +3
  • Distant (over 1,000 light-years) · +6
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • White A-type star · +5
  • Subgiant (leaving the main sequence) · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads A2/A3IV — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

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 7.4 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagittarius.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Could we get there?

  • Verdict. Impossible with our current technology — and the next millennium of it.

Getting there

  • Aboard Voyager 1. ≈ 25.9 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 2.3 million years even at the Parker Solar Probe's 192 km/s.

Properties

absmag
-0.898
bv
0.123
constellation
Sgr
dist ly
1475.819
luminosity
199.159
mag
7.38
name
HD 181039
spect
A2/A3IV

About HD 181039

HD 181039 is an uncommon star. It lies about 1,475.8 light-years from Earth, sits in the constellation Sgr, shines at apparent magnitude 7.38 and has spectral type A2/A3IV.

Its spectrum reads A2/A3IV — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for HD 181039 in the constellation Sgr. At apparent magnitude 7.38, it is an easy target for binoculars.

Like any astronomical target, HD 181039 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 181039 is an uncommon star

HD 181039 scores 30 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 4 points would lift it into a rarer tier.

That score comes from 6 science badges — Star, Distant (over 1,000 light-years), Toward the galactic centre, On the zodiac, White A-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.