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Rare variable star 45 EP

HD 137613

RA 231.9513° · Dec -25.1695° · star

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Score breakdown

· 6 badges
45 pts · Rare
Rare 50 pts → Epic
  • Carbon star (sooty red) +24
  • Distant (over 1,000 light-years) +6
  • Variable star +5
  • Gently variable +4
  • On the zodiac +3
  • A named variable star +3
Total score 45

5 more points to reach Epic.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • On the zodiac · +3
  • Carbon star (sooty red) · +24
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads C — a carbon star, wrapped in so much soot that its light is filtered to a deep ruby red.
  • 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 7.5 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Libra.
  • 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 May — 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. ≈ 34.1 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-1.383
bv
1.193
constellation
Lib
dist ly
1941.4048
luminosity
311.315
mag
7.49
name
HD 137613
spect
C
var amplitude
0.08
var designation
HM
var max
7.446
var min
7.526

About HD 137613

HD 137613 is a rare variable star. It lies about 1,941.4 light-years from Earth, sits in the constellation Lib, shines at apparent magnitude 7.49 and has spectral type C.

Its spectrum reads C — a carbon star, wrapped in so much soot that its light is filtered to a deep ruby red.

How to see it

Look for HD 137613 in the constellation Lib. At apparent magnitude 7.49, it is an easy target for binoculars.

Like any astronomical target, HD 137613 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 137613 is a rare variable star

HD 137613 scores 45 points on Spacedle's rarity scale, which places it in the rare tier. Another 5 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Distant (over 1,000 light-years), On the zodiac, Carbon star (sooty red), 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.