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Trash star 9 EP

HD 21117

RA 51.6643° · Dec 50.8465° · star

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Score breakdown

· 2 badges
9 pts · Trash
Trash 15 pts → Common
  • Hot blue B-type star +6
  • Star +3
Total score 9

6 more points to reach Common.

Badges

  • Star · +3
  • Hot blue B-type star · +6

Trivia

What it actually is

  • Spectral class. Its spectrum reads B8 — 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.

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 7.6 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Perseus.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around November — 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. ≈ 9.1 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 808.4 thousand years even at the Parker Solar Probe's 192 km/s.

Properties

absmag
1.637
bv
0.092
constellation
Per
dist ly
517.7081
luminosity
19.2841
mag
7.64
name
HD 21117
spect
B8

About HD 21117

HD 21117 is a trash star. It lies about 517.7 light-years from Earth, sits in the constellation Per, shines at apparent magnitude 7.64 and has spectral type B8.

Its spectrum reads B8 — 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 HD 21117 in the constellation Per. At apparent magnitude 7.64, it is an easy target for binoculars.

Like any astronomical target, HD 21117 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 21117 is a trash star

HD 21117 scores 9 points on Spacedle's rarity scale, which places it in the trash tier. Another 6 points would lift it into a rarer tier.

That score comes from 2 science badges — Star and Hot blue B-type 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.