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Uncommon star 31 EP

HR 7993

RA 312.3225° · Dec 64.0423° · star

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Score breakdown

· 6 badges
31 pts · Uncommon
Uncommon 34 pts → Rare
  • Intrinsically luminous (Mv < −2) +10
  • Distant (over 1,000 light-years) +6
  • Hot blue B-type star +6
  • Never sets (northern circumpolar) +4
  • Star +3
  • Main-sequence star +2
Total score 31

3 more points to reach Rare.

Badges

  • Star · +3
  • Distant (over 1,000 light-years) · +6
  • Never sets (northern circumpolar) · +4
  • Hot blue B-type star · +6
  • Main-sequence star · +2
  • Intrinsically luminous (Mv < −2) · +10

Trivia

What it actually is

  • Spectral class. Its spectrum reads B0.5V — 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 on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.

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 6.5 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cepheus.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • Best time of year. It stands highest in the middle of the night around August — 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. ≈ 38 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-2.655
bv
0.025
constellation
Cep
dist ly
2159.9737
luminosity
1004.6158
mag
6.45
name
HR 7993
spect
B0.5V

About HR 7993

HR 7993 is an uncommon star. It lies about 2,160 light-years from Earth, sits in the constellation Cep, shines at apparent magnitude 6.45 and has spectral type B0.5V.

Its spectrum reads B0.5V — 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 7993 in the constellation Cep. At apparent magnitude 6.45, it is an easy target for binoculars.

Like any astronomical target, HR 7993 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 7993 is an uncommon star

HR 7993 scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 3 points would lift it into a rarer tier.

That score comes from 6 science badges — Star, Distant (over 1,000 light-years), Never sets (northern circumpolar), Hot blue B-type star, Main-sequence star and Intrinsically luminous (Mv < −2) — 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.