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Common star 15 EP

HD 197801

RA 311.5661° · Dec -12.8099° · star

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Score breakdown

· 4 badges
15 pts · Common
Common 22 pts → Uncommon
  • Giant star +6
  • Star +3
  • On the zodiac +3
  • Orange K-type star +3
Total score 15

7 more points to reach Uncommon.

Badges

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

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 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 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Aquarius.
  • 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 1.3) — 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 4120 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
-11.16
bv
1.302
constellation
Aqr
luminosity
2535128.6305
mag
8.84
name
HD 197801
spect
K2/K3III

Nearby objects

About HD 197801

HD 197801 is a common star. It sits in the constellation Aqr, shines at apparent magnitude 8.84 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 197801 in the constellation Aqr. At apparent magnitude 8.84, it is an easy target for binoculars.

Like any astronomical target, HD 197801 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 197801 is a common star

HD 197801 scores 15 points on Spacedle's rarity scale, which places it in the common tier. Another 7 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, On the zodiac, 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.