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Uncommon variable star 28 EP

HD 147173

RA 246.1513° · Dec -65.7218° · star

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Score breakdown

· 6 badges
28 pts · Uncommon
Uncommon 34 pts → Rare
  • Distant (over 1,000 light-years) +6
  • Variable star +5
  • White A-type star +5
  • Blue-white star +5
  • Gently variable +4
  • A named variable star +3
Total score 28

6 more points to reach Rare.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • White A-type star · +5
  • Blue-white star · +5
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads Ap Si — 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 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Triangulum Australe.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around May — that's when to go looking.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 51.2 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-0.954
bv
-0.091
constellation
TrA
dist ly
2912.107
luminosity
209.7008
mag
8.8
name
HD 147173
spect
Ap Si
var amplitude
0.14
var designation
MR
var max
8.728
var min
8.868

About HD 147173

HD 147173 is an uncommon variable star. It lies about 2,912.1 light-years from Earth, sits in the constellation TrA, shines at apparent magnitude 8.8 and has spectral type Ap Si.

Its spectrum reads Ap Si — 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 147173 in the constellation TrA. At apparent magnitude 8.8, it is an easy target for binoculars.

Like any astronomical target, HD 147173 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 147173 is an uncommon variable star

HD 147173 scores 28 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 6 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Distant (over 1,000 light-years), White A-type star, Blue-white 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.