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Trash star 12 EP

HD 21493

RA 51.5528° · Dec -43.8167° · star

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Score breakdown

· 3 badges
12 pts · Trash
Trash 15 pts → Common
  • Giant star +6
  • Star +3
  • Orange K-type star +3
Total score 12

3 more points to reach Common.

Badges

  • Star · +3
  • Orange K-type star · +3
  • Giant star · +6

Trivia

Hard to believe

  • True brightness. It pours out about 2.8 million times as much light as the Sun. It only looks ordinary because it is so far away.

What it actually is

  • Spectral class. Its spectrum reads K2/K3III — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.

Find it in the sky

  • How to spot it. At magnitude 8.7 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Eridanus.
  • 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 November — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.4) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 4030 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HD number is from the Henry Draper Catalogue, in which Annie Jump Cannon personally classified the spectra of nearly 400,000 stars — still the largest such feat by one person.

Properties

absmag
-11.29
bv
1.351
constellation
Eri
luminosity
2857590.5434
mag
8.71
name
HD 21493
spect
K2/K3III

Nearby objects

About HD 21493

HD 21493 is a trash star. It sits in the constellation Eri, shines at apparent magnitude 8.71 and has spectral type K2/K3III.

Its spectrum reads K2/K3III — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.

How to see it

Look for HD 21493 in the constellation Eri. At apparent magnitude 8.71, it is an easy target for binoculars.

Like any astronomical target, HD 21493 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 21493 is a trash star

HD 21493 scores 12 points on Spacedle's rarity scale, which places it in the trash tier. Another 3 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Orange K-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.