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Rare variable star 40 EP

HD 18142

RA 43.9220° · Dec 31.0431° · star

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Score breakdown

· 7 badges
40 pts · Rare
Rare 50 pts → Epic
  • Bright giant +12
  • Deep red star +8
  • 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
  • On the zodiac · +3
  • Cool red M-type star · +5
  • Bright giant · +12
  • Deep red star · +8
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M3II-III — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.
  • Where it is in life. It is a bright giant, well on its way to the largest stars there are.
  • 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 6.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Aries.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • 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.

Properties

absmag
-0.194
bv
1.749
constellation
Ari
dist ly
851.5822
luminosity
104.1358
mag
6.89
name
HD 18142
spect
M3II-III
var amplitude
0.12
var designation
AO
var max
6.827
var min
6.947

About HD 18142

HD 18142 is a rare variable star. It lies about 851.6 light-years from Earth, sits in the constellation Ari, shines at apparent magnitude 6.89 and has spectral type M3II-III.

Its spectrum reads M3II-III — 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 18142 in the constellation Ari. At apparent magnitude 6.89, it is an easy target for binoculars.

Like any astronomical target, HD 18142 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 18142 is a rare variable star

HD 18142 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 7 science badges — Variable star, On the zodiac, Cool red M-type star, Bright giant, Deep red 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.