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Rare variable star 39 EP

HD 155637

RA 257.1021° · Dec 64.3191° · star

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Score breakdown

· 7 badges
39 pts · Rare
Rare 50 pts → Epic
  • Strongly variable +10
  • Distant (over 1,000 light-years) +6
  • Red dwarf +6
  • Variable star +5
  • Cool red M-type star +5
  • Never sets (northern circumpolar) +4
  • A named variable star +3
Total score 39

11 more points to reach Epic.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • Never sets (northern circumpolar) · +4
  • Cool red M-type star · +5
  • Red dwarf · +6
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M8p(S) — 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 9.7 you'll want a small backyard telescope, over in Draco.
  • 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 June — 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. ≈ 29.2 million years at Voyager 1's speed (17 km/s).

Properties

absmag
1.111
bv
1.239
constellation
Dra
dist ly
1664.0613
luminosity
31.304
mag
9.65
name
HD 155637
spect
M8p(S)
var amplitude
0.64
var designation
TV
var max
9.408
var min
10.048

About HD 155637

HD 155637 is a rare variable star. It lies about 1,664.1 light-years from Earth, sits in the constellation Dra, shines at apparent magnitude 9.65 and has spectral type M8p(S).

Its spectrum reads M8p(S) — 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 155637 in the constellation Dra. At apparent magnitude 9.65, a small backyard telescope will bring it into view.

Like any astronomical target, HD 155637 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 155637 is a rare variable star

HD 155637 scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 11 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Distant (over 1,000 light-years), Never sets (northern circumpolar), Cool red M-type star, Red dwarf, 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.