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Rare variable star 44 EP

HD 158377

RA 262.4319° · Dec -19.4730° · star

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Score breakdown

· 5 badges
44 pts · Rare
Rare 50 pts → Epic
  • Carbon star (sooty red) +24
  • Deep red star +8
  • Variable star +5
  • Gently variable +4
  • A named variable star +3
Total score 44

6 more points to reach Epic.

Badges

  • Variable star · +5
  • Carbon star (sooty red) · +24
  • Deep red star · +8
  • 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.

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 Ophiuchus.
  • 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 June — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out deep orange-red (B−V 2.1) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3070 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HD number is from the Henry Draper Catalogue, in which Annie Jump Cannon personally classified the spectra of nearly 400,000 stars — still the largest such feat by one person.

Properties

absmag
-12.49
bv
2.1
constellation
Oph
luminosity
8629785.4777
mag
7.51
name
HD 158377
spect
C
var amplitude
0.49
var designation
TW
var max
7.162
var min
7.652

About HD 158377

HD 158377 is a rare variable star. It sits in the constellation Oph, shines at apparent magnitude 7.51 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 158377 in the constellation Oph. At apparent magnitude 7.51, it is an easy target for binoculars.

Like any astronomical target, HD 158377 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 158377 is a rare variable star

HD 158377 scores 44 points on Spacedle's rarity scale, which places it in the rare tier. Another 6 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Carbon star (sooty red), 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.