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Uncommon variable star 23 EP

HD 139792

RA 235.7427° · Dec -58.1147° · star

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Score breakdown

· 5 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Giant star +6
  • Variable star +5
  • Cool red M-type star +5
  • Gently variable +4
  • A named variable star +3
Total score 23

11 more points to reach Rare.

Badges

  • Variable star · +5
  • Cool red M-type star · +5
  • Giant star · +6
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M3III+... — 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 giant. It has already exhausted its core hydrogen and swollen up enormously in response.
  • 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 Norma.
  • 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.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.2) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 4240 K, against the Sun's 5778 K.

Properties

absmag
-12.51
bv
1.234
constellation
Nor
luminosity
8790225.1683
mag
7.49
name
HD 139792
spect
M3III+...
var amplitude
0.17
var designation
V359
var max
7.423
var min
7.593

About HD 139792

HD 139792 is an uncommon variable star. It sits in the constellation Nor, shines at apparent magnitude 7.49 and has spectral type M3III+....

Its spectrum reads M3III+... — 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 139792 in the constellation Nor. At apparent magnitude 7.49, it is an easy target for binoculars.

Like any astronomical target, HD 139792 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 139792 is an uncommon variable star

HD 139792 scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Cool red M-type star, Giant 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.