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Trash star 10 EP

HD 83021

RA 144.6232° · Dec 65.1221° · star

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Score breakdown

· 3 badges
10 pts · Trash
Trash 15 pts → Common
  • Never sets (northern circumpolar) +4
  • Star +3
  • Orange K-type star +3
Total score 10

5 more points to reach Common.

Badges

  • Star · +3
  • Never sets (northern circumpolar) · +4
  • Orange K-type star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 2 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 K0 — 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 9.1 you'll want a small backyard telescope, over in Ursa Major.
  • 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 February — 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) — 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 4670 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
-10.91
bv
1.032
constellation
UMa
luminosity
2013724.2499
mag
9.09
name
HD 83021
spect
K0

Nearby objects

About HD 83021

HD 83021 is a trash star. It sits in the constellation UMa, shines at apparent magnitude 9.09 and has spectral type K0.

Its spectrum reads K0 — 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 83021 in the constellation UMa. At apparent magnitude 9.09, a small backyard telescope will bring it into view.

Like any astronomical target, HD 83021 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 83021 is a trash star

HD 83021 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, Never sets (northern circumpolar) and Orange K-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.