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Common star 21 EP

HR 7639

RA 300.3616° · Dec -40.8143° · star

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Score breakdown

· 5 badges
21 pts · Common
Common 22 pts → Uncommon
  • Toward the galactic centre +8
  • White A-type star +5
  • Star +3
  • On the zodiac +3
  • Main-sequence star +2
Total score 21

1 more point to reach Uncommon.

Badges

  • Star · +3
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • White A-type star · +5
  • Main-sequence star · +2

Trivia

What it actually is

  • Spectral class. Its spectrum reads A2/A3V — 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 6.3 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. Hopelessly far for any craft humanity can build today.

Getting there

  • Aboard Voyager 1. ≈ 5.7 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 508.8 thousand years even at the Parker Solar Probe's 192 km/s.

Properties

absmag
1.312
bv
0.113
constellation
Sgr
dist ly
325.8302
luminosity
26.0136
mag
6.31
name
HR 7639
spect
A2/A3V

About HR 7639

HR 7639 is a common star. It lies about 325.8 light-years from Earth, sits in the constellation Sgr, shines at apparent magnitude 6.31 and has spectral type A2/A3V.

Its spectrum reads A2/A3V — 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 HR 7639 in the constellation Sgr. At apparent magnitude 6.31, it is an easy target for binoculars.

Like any astronomical target, HR 7639 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 HR 7639 is a common star

HR 7639 scores 21 points on Spacedle's rarity scale, which places it in the common tier. Another 1 point would lift it into a rarer tier.

That score comes from 5 science badges — Star, Toward the galactic centre, On the zodiac, White A-type star and Main-sequence 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.