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Common variable star 15 EP

HD 220978

RA 352.1051° · Dec -25.4205° · star

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Score breakdown

· 4 badges
15 pts · Common
Common 22 pts → Uncommon
  • Variable star +5
  • White A-type star +5
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 15

7 more points to reach Uncommon.

Badges

  • Variable star · +5
  • White A-type star · +5
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads A3 — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.
  • 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 6.9 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 September — that's when to go looking.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 6.4 million years at Voyager 1's speed (17 km/s).

Properties

absmag
1.645
bv
0.16
constellation
Scl
dist ly
366.8795
luminosity
19.1426
mag
6.9
name
HD 220978
spect
A3
var amplitude
0.04
var designation
BS
var max
6.879
var min
6.919

About HD 220978

HD 220978 is a common variable star. It lies about 366.9 light-years from Earth, sits in the constellation Scl, shines at apparent magnitude 6.9 and has spectral type A3.

Its spectrum reads A3 — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for HD 220978 in the constellation Scl. At apparent magnitude 6.9, it is an easy target for binoculars.

Like any astronomical target, HD 220978 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 220978 is a common variable star

HD 220978 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 — Variable star, White A-type star, 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.