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Uncommon variable star 27 EP

HD 215661

RA 341.2609° · Dec 68.1329° · star

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Score breakdown

· 5 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Strongly variable +10
  • Variable star +5
  • White A-type star +5
  • Never sets (northern circumpolar) +4
  • A named variable star +3
Total score 27

7 more points to reach Rare.

Badges

  • Variable star · +5
  • Never sets (northern circumpolar) · +4
  • White A-type star · +5
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads A2p — 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 8.6 it is just past naked-eye reach — ordinary binoculars will pull it in, 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.

Getting there

  • Aboard Voyager 1. ≈ 7.6 million years at Voyager 1's speed (17 km/s).

Properties

absmag
3.031
bv
0.285
constellation
Cep
dist ly
429.718
luminosity
5.3407
mag
8.63
name
HD 215661
spect
A2p
var amplitude
1.62
var designation
ZZ
var max
8.47
var min
10.09

About HD 215661

HD 215661 is an uncommon variable star. It lies about 429.7 light-years from Earth, sits in the constellation Cep, shines at apparent magnitude 8.63 and has spectral type A2p.

Its spectrum reads A2p — 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 215661 in the constellation Cep. At apparent magnitude 8.63, it is an easy target for binoculars.

Like any astronomical target, HD 215661 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 215661 is an uncommon variable star

HD 215661 scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Never sets (northern circumpolar), White A-type star, Strongly 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.