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Trash star 11 EP

HD 210917

RA 333.6131° · Dec -37.7925° · star

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Score breakdown

· 3 badges
11 pts · Trash
Trash 15 pts → Common
  • Subgiant (leaving the main sequence) +5
  • Star +3
  • Orange K-type star +3
Total score 11

4 more points to reach Common.

Badges

  • Star · +3
  • Orange K-type star · +3
  • Subgiant (leaving the main sequence) · +5

Trivia

Hard to believe

  • True brightness. It pours out about 2.5 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 K1IV — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.
  • Where it is in life. It is a subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.

Find it in the sky

  • How to spot it. At magnitude 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Grus.
  • 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 August — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.2) — 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 4260 K, against the Sun's 5778 K.

Properties

absmag
-11.17
bv
1.227
constellation
Gru
luminosity
2558585.8869
mag
8.83
name
HD 210917
spect
K1IV

Nearby objects

About HD 210917

HD 210917 is a trash star. It sits in the constellation Gru, shines at apparent magnitude 8.83 and has spectral type K1IV.

Its spectrum reads K1IV — 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 210917 in the constellation Gru. At apparent magnitude 8.83, it is an easy target for binoculars.

Like any astronomical target, HD 210917 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 210917 is a trash star

HD 210917 scores 11 points on Spacedle's rarity scale, which places it in the trash tier. Another 4 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Orange K-type star and Subgiant (leaving the main sequence) — 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.