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Uncommon variable star 23 EP

HD 222217

RA 354.5845° · Dec 64.3341° · star

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Score breakdown

· 6 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Variable star +5
  • White A-type star +5
  • Never sets (northern circumpolar) +4
  • Gently variable +4
  • A named variable star +3
  • Main-sequence star +2
Total score 23

11 more points to reach Rare.

Badges

  • Variable star · +5
  • Never sets (northern circumpolar) · +4
  • White A-type star · +5
  • Main-sequence star · +2
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads A7V — 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.
  • Where it is in life. It is on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.
  • 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 9.2 you'll want a small backyard telescope, over in Cepheus.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • 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.

Properties

absmag
2.243
bv
0.291
constellation
Cep
dist ly
799.4018
luminosity
11.0357
mag
9.19
name
HD 222217
spect
A7V
var amplitude
0.4
var designation
XX
var max
9.147
var min
9.547

About HD 222217

HD 222217 is an uncommon variable star. It lies about 799.4 light-years from Earth, sits in the constellation Cep, shines at apparent magnitude 9.19 and has spectral type A7V.

Its spectrum reads A7V — 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 222217 in the constellation Cep. At apparent magnitude 9.19, a small backyard telescope will bring it into view.

Like any astronomical target, HD 222217 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 222217 is an uncommon variable star

HD 222217 scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Never sets (northern circumpolar), White A-type star, Main-sequence 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.