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Uncommon variable star 32 EP

HD 217932

RA 346.0717° · Dec -16.0100° · star

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Score breakdown

· 6 badges
32 pts · Uncommon
Uncommon 34 pts → Rare
  • Strongly variable +10
  • Red dwarf +6
  • Variable star +5
  • Cool red M-type star +5
  • On the zodiac +3
  • A named variable star +3
Total score 32

2 more points to reach Rare.

Badges

  • Variable star · +5
  • On the zodiac · +3
  • Cool red M-type star · +5
  • Red dwarf · +6
  • Strongly variable · +10
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 1.7 million 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 M3/M4 — 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 9.2 you'll want a small backyard telescope, over in Aquarius.
  • 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 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 1.4) — 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 4000 K, against the Sun's 5778 K.

Properties

absmag
-10.75
bv
1.368
constellation
Aqr
luminosity
1737800.8287
mag
9.25
name
HD 217932
spect
M3/M4
var amplitude
0.54
var designation
EQ
var max
9.041
var min
9.581

About HD 217932

HD 217932 is an uncommon variable star. It sits in the constellation Aqr, shines at apparent magnitude 9.25 and has spectral type M3/M4.

Its spectrum reads M3/M4 — 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 217932 in the constellation Aqr. At apparent magnitude 9.25, a small backyard telescope will bring it into view.

Like any astronomical target, HD 217932 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 217932 is an uncommon variable star

HD 217932 scores 32 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 2 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, On the zodiac, 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.