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Uncommon star 32 EP

HR 7155

RA 284.5854° · Dec -24.8769° · star

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Score breakdown

· 6 badges
32 pts · Uncommon
Uncommon 34 pts → Rare
  • Toward the galactic centre +8
  • Distant (over 1,000 light-years) +6
  • Hot blue B-type star +6
  • Giant star +6
  • Star +3
  • On the zodiac +3
Total score 32

2 more points to reach Rare.

Badges

  • Star · +3
  • Distant (over 1,000 light-years) · +6
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Giant star · +6

Trivia

What it actually is

  • Spectral class. Its spectrum reads B8III — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
  • 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 6.6 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. ≈ 20.2 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-1.113
bv
0.055
constellation
Sgr
dist ly
1148.4367
luminosity
242.7728
mag
6.62
name
HR 7155
spect
B8III

About HR 7155

HR 7155 is an uncommon star. It lies about 1,148.4 light-years from Earth, sits in the constellation Sgr, shines at apparent magnitude 6.62 and has spectral type B8III.

Its spectrum reads B8III — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for HR 7155 in the constellation Sgr. At apparent magnitude 6.62, it is an easy target for binoculars.

Like any astronomical target, HR 7155 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 7155 is an uncommon star

HR 7155 scores 32 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 2 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, Hot blue B-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.