Uncommon variable star 26 EP

HD 203177

RA 320.2086° · Dec -9.1517° · star

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Score breakdown

· 6 badges

26 pts · Uncommon

Uncommon 34 pts → Rare

Deep red star +8
Variable star +5
Gently variable +4
On the zodiac +3
Orange K-type star +3
A named variable star +3

Total score 26

8 more points to reach Rare.

Badges

Variable star · +5
On the zodiac · +3
Orange K-type star · +3
Deep red star · +8
Gently variable · +4
A named variable star · +3

Trivia

What it actually is

Spectral class. Its spectrum reads K2 — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.
It changes. This star does not hold still: its brightness rises and falls on a rhythm of hours, days or years, either pulsing in size or being eclipsed by a companion.

Find it in the sky

How to spot it. At magnitude 7.5 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Aquarius.
Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
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 deep orange-red (B−V 1.6) — one of the coolest surfaces a star can have while still fusing.

By the numbers

Surface temperature. Its colour puts the surface at roughly 3670 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: -12.55
bv: 1.587
constellation: Aqr
luminosity: 9120108.3936
mag: 7.45
name: HD 203177
spect: K2
var amplitude: 0.11
var designation: IX
var max: 7.38
var min: 7.49

Nearby objects

About HD 203177

HD 203177 is an uncommon variable star. It sits in the constellation Aqr, shines at apparent magnitude 7.45 and has spectral type K2.

Its spectrum reads K2 — 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 203177 in the constellation Aqr. At apparent magnitude 7.45, it is an easy target for binoculars.

Like any astronomical target, HD 203177 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 203177 is an uncommon variable star

HD 203177 scores 26 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 8 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, On the zodiac, Orange K-type star, Deep red star, Gently variable and A named variable 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.