Common star 15 EP

HD 221790

RA 353.7985° · Dec -18.5718° · 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 4.2 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 K0III+... — 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 giant. It has already exhausted its core hydrogen and swollen up enormously in response.

Find it in the sky

How to spot it. At magnitude 8.3 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 September — that's when to go looking.

Its true colour

Its true colour. Measured through blue and visual filters it comes out yellow-white (B−V 0.4) — a shade brighter and crisper than our own Sun.
Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

Properties

absmag: -11.74
bv: 0.4
constellation: Aqr
luminosity: 4325138.3104
mag: 8.26
name: HD 221790
spect: K0III+...

Nearby objects

About HD 221790

HD 221790 is a common star. It sits in the constellation Aqr, shines at apparent magnitude 8.26 and has spectral type K0III+....

Its spectrum reads K0III+... — 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 221790 in the constellation Aqr. At apparent magnitude 8.26, it is an easy target for binoculars.

Like any astronomical target, HD 221790 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 221790 is a common star

HD 221790 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.