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Uncommon variable star 33 EP

HD 21190

RA 47.4742° · Dec -83.5316° · star

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Score breakdown

· 5 badges
33 pts · Uncommon
Uncommon 34 pts → Rare
  • Supergiant +18
  • Variable star +5
  • Gently variable +4
  • Yellow-white F-type star +3
  • A named variable star +3
Total score 33

1 more point to reach Rare.

Badges

  • Variable star · +5
  • Yellow-white F-type star · +3
  • Supergiant · +18
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads F2/F3Ib/II — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • 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 7.6 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Octans.
  • 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 November — 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. ≈ 13.7 million years at Voyager 1's speed (17 km/s).

Properties

absmag
0.711
bv
0.38
constellation
Oct
dist ly
782.1488
luminosity
45.2481
mag
7.61
name
HD 21190
spect
F2/F3Ib/II
var amplitude
0.09
var designation
CP
var max
7.57
var min
7.66

About HD 21190

HD 21190 is an uncommon variable star. It lies about 782.1 light-years from Earth, sits in the constellation Oct, shines at apparent magnitude 7.61 and has spectral type F2/F3Ib/II.

Its spectrum reads F2/F3Ib/II — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for HD 21190 in the constellation Oct. At apparent magnitude 7.61, it is an easy target for binoculars.

Like any astronomical target, HD 21190 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 21190 is an uncommon variable star

HD 21190 scores 33 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 1 point would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Yellow-white F-type star, Supergiant, 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.