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Rare variable star 40 EP

HD 220686

RA 351.4497° · Dec -11.1556° · star

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Score breakdown

· 8 badges
40 pts · Rare
Rare 50 pts → Epic
  • Deep red star +8
  • Distant (over 1,000 light-years) +6
  • Red dwarf +6
  • Variable star +5
  • Cool red M-type star +5
  • Gently variable +4
  • On the zodiac +3
  • A named variable star +3
Total score 40

10 more points to reach Epic.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • On the zodiac · +3
  • Cool red M-type star · +5
  • Deep red star · +8
  • Red dwarf · +6
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M3 — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.
  • 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 8.1 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Aquarius.
  • 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. Impossible with our current technology — and the next millennium of it.

Getting there

  • Aboard Voyager 1. ≈ 17.7 million years at Voyager 1's speed (17 km/s).

Properties

absmag
0.693
bv
1.411
constellation
Aqr
dist ly
1006.6544
luminosity
46.0045
mag
8.14
name
HD 220686
spect
M3
var amplitude
0.17
var designation
LT
var max
8.026
var min
8.196

About HD 220686

HD 220686 is a rare variable star. It lies about 1,006.7 light-years from Earth, sits in the constellation Aqr, shines at apparent magnitude 8.14 and has spectral type M3.

Its spectrum reads M3 — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

How to see it

Look for HD 220686 in the constellation Aqr. At apparent magnitude 8.14, it is an easy target for binoculars.

Like any astronomical target, HD 220686 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 220686 is a rare variable star

HD 220686 scores 40 points on Spacedle's rarity scale, which places it in the rare tier. Another 10 points would lift it into a rarer tier.

That score comes from 8 science badges — Variable star, Distant (over 1,000 light-years), On the zodiac, Cool red M-type star, Deep red star, Red dwarf, 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.