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Uncommon variable star 23 EP

HIP 117239

RA 356.5789° · Dec 24.8559° · star

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Score breakdown

· 5 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Red dwarf +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
  • Red dwarf · +6
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 648.6 thousand times as much light as the Sun. It only looks ordinary because it is so far away.

What it actually is

  • Spectral class. Its spectrum reads M0 — 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.

Find it in the sky

  • How to spot it. At magnitude 10.3 you'll want a small backyard telescope, over in Pegasus.
  • 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 September — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.3) — 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 4090 K, against the Sun's 5778 K.

Properties

absmag
-9.7
bv
1.316
constellation
Peg
luminosity
660693.448
mag
10.3
name
HIP 117239
spect
M0
var amplitude
0.36
var designation
V358
var max
10.223
var min
10.583

About HIP 117239

HIP 117239 is an uncommon variable star. It sits in the constellation Peg, shines at apparent magnitude 10.3 and has spectral type M0.

Its spectrum reads M0 — 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 HIP 117239 in the constellation Peg. At apparent magnitude 10.3, a small backyard telescope will bring it into view.

Like any astronomical target, HIP 117239 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 HIP 117239 is an uncommon variable star

HIP 117239 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, Red dwarf, 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.