← Back to dex
Trash star 10 EP

HD 20931

RA 51.1251° · Dec 49.1399° · star

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 3 badges
10 pts · Trash
Trash 15 pts → Common
  • White A-type star +5
  • Star +3
  • Main-sequence star +2
Total score 10

5 more points to reach Common.

Badges

  • Star · +3
  • White A-type star · +5
  • Main-sequence star · +2

Trivia

What it actually is

  • Spectral class. Its spectrum reads A1V — 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.
  • 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 7.9 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. ≈ 7.9 million years at Voyager 1's speed (17 km/s).

Properties

absmag
2.173
bv
0.09
constellation
Per
dist ly
451.7398
luminosity
11.7706
mag
7.88
name
HD 20931
spect
A1V

About HD 20931

HD 20931 is a trash star. It lies about 451.7 light-years from Earth, sits in the constellation Per, shines at apparent magnitude 7.88 and has spectral type A1V.

Its spectrum reads A1V — 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 20931 in the constellation Per. At apparent magnitude 7.88, it is an easy target for binoculars.

Like any astronomical target, HD 20931 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 20931 is a trash star

HD 20931 scores 10 points on Spacedle's rarity scale, which places it in the trash tier. Another 5 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, 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.