Uncommon variable star 31 EP

HD 155638

RA 257.6067° · Dec 48.9656° · star

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Score breakdown

· 6 badges

31 pts · Uncommon

Uncommon 34 pts → Rare

Sun-like G-type star +8
Distant (over 1,000 light-years) +6
Variable star +5
Subgiant (leaving the main sequence) +5
Gently variable +4
A named variable star +3

Total score 31

3 more points to reach Rare.

Badges

Variable star · +5
Distant (over 1,000 light-years) · +6
Sun-like G-type star · +8
Subgiant (leaving the main sequence) · +5
Gently variable · +4
A named variable star · +3

Trivia

What it actually is

Spectral class. Its spectrum reads G8IV — a G-type star: the very same spectral class as our own Sun.
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.
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.

Sense of scale

In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

How to spot it. At magnitude 8.1 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Hercules.
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 June — that's when to go looking.

Could we get there?

Verdict. Impossible with our current technology — and the next millennium of it.

Properties

absmag: 0.104
bv: 0.923
constellation: Her
dist ly: 1284.0788
luminosity: 79.1407
mag: 8.08
name: HD 155638
spect: G8IV
var amplitude: 0.46
var designation: V792
var max: 7.979
var min: 8.439

Nearby objects

About HD 155638

HD 155638 is an uncommon variable star. It lies about 1,284.1 light-years from Earth, sits in the constellation Her, shines at apparent magnitude 8.08 and has spectral type G8IV.

Its spectrum reads G8IV — a G-type star: the very same spectral class as our own Sun.

How to see it

Look for HD 155638 in the constellation Her. At apparent magnitude 8.08, it is an easy target for binoculars.

Like any astronomical target, HD 155638 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 155638 is an uncommon variable star

HD 155638 scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 3 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Distant (over 1,000 light-years), Sun-like G-type star, Subgiant (leaving the main sequence), 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.