Rare variable star 40 EP

HD 195665

RA 307.9022° · Dec 32.5645° · star

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Score breakdown

· 5 badges

40 pts · Rare

Rare 50 pts → Epic

S-type star (zirconium giant) +20
Deep red star +8
Variable star +5
Gently variable +4
A named variable star +3

Total score 40

10 more points to reach Epic.

Badges

Variable star · +5
S-type star (zirconium giant) · +20
Deep red star · +8
Gently variable · +4
A named variable star · +3

Trivia

Hard to believe

True brightness. It pours out about 3.1 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 S58v — an S-type giant, its atmosphere laced with zirconium dredged up from the fusion going on below.
Where it is in life. It is on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.
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 8.6 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cygnus.
Northern sky. It rides the northern half of the sky — an easier target the further north you are.
Best time of year. It stands highest in the middle of the night around July — 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 2.5) — one of the coolest surfaces a star can have while still fusing.

Properties

absmag: -11.39
bv: 2.457
constellation: Cyg
luminosity: 3133285.7243
mag: 8.61
name: HD 195665
spect: S58v
var amplitude: 0.4
var designation: AD
var max: 8.463
var min: 8.863

Nearby objects

About HD 195665

HD 195665 is a rare variable star. It sits in the constellation Cyg, shines at apparent magnitude 8.61 and has spectral type S58v.

Its spectrum reads S58v — an S-type giant, its atmosphere laced with zirconium dredged up from the fusion going on below.

How to see it

Look for HD 195665 in the constellation Cyg. At apparent magnitude 8.61, it is an easy target for binoculars.

Like any astronomical target, HD 195665 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 195665 is a rare variable star

HD 195665 scores 40 points on Spacedle's rarity scale, which places it in the rare tier. Another 10 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, S-type star (zirconium giant), 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.