Common variable star 18 EP

HD 6491

RA 16.3941° · Dec -26.9551° · star

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Score breakdown

· 5 badges

18 pts · Common

Common 22 pts → Uncommon

Variable star +5
Subgiant (leaving the main sequence) +5
Yellow-white F-type star +3
A named variable star +3
Barely variable (under 0.05 mag) +2

Total score 18

4 more points to reach Uncommon.

Badges

Variable star · +5
Yellow-white F-type star · +3
Subgiant (leaving the main sequence) · +5
Barely variable (under 0.05 mag) · +2
A named variable star · +3

Trivia

What it actually is

Spectral class. Its spectrum reads F2IV/V — an F-type star — a little hotter, whiter and shorter-lived than the 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 Sculptor.
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 October — that's when to go looking.

Could we get there?

Verdict. Hopelessly far for any craft humanity can build today.

Properties

absmag: 2.306
bv: 0.388
constellation: Scl
dist ly: 478.9369
luminosity: 10.4136
mag: 8.14
name: HD 6491
spect: F2IV/V
var amplitude: 0.04
var designation: AS
var max: 8.124
var min: 8.164

Nearby objects

About HD 6491

HD 6491 is a common variable star. It lies about 478.9 light-years from Earth, sits in the constellation Scl, shines at apparent magnitude 8.14 and has spectral type F2IV/V.

Its spectrum reads F2IV/V — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for HD 6491 in the constellation Scl. At apparent magnitude 8.14, it is an easy target for binoculars.

Like any astronomical target, HD 6491 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 6491 is a common variable star

HD 6491 scores 18 points on Spacedle's rarity scale, which places it in the common tier. Another 4 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Yellow-white F-type star, Subgiant (leaving the main sequence), Barely variable (under 0.05 mag) 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.