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Epic variable star 50 EP

HD 188378

RA 298.9851° · Dec -29.1900° · star

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Score breakdown

· 7 badges
50 pts · Epic
Epic 78 pts → Anomaly
  • Dramatic variable (over 2 magnitudes) +20
  • Toward the galactic centre +8
  • Red dwarf +6
  • Variable star +5
  • Cool red M-type star +5
  • On the zodiac +3
  • A named variable star +3
Total score 50

28 more points to reach Anomaly.

Badges

  • Variable star · +5
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • Cool red M-type star · +5
  • Red dwarf · +6
  • Dramatic variable (over 2 magnitudes) · +20
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 3.1 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 M5e — 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 8.6 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagittarius.
  • 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 July — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.1) — 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 4550 K, against the Sun's 5778 K.

Properties

absmag
-11.4
bv
1.086
constellation
Sgr
luminosity
3162277.6602
mag
8.6
name
HD 188378
spect
M5e
var amplitude
3.86
var designation
RR
var max
6.768
var min
10.628

About HD 188378

HD 188378 is an epic variable star. It sits in the constellation Sgr, shines at apparent magnitude 8.6 and has spectral type M5e.

Its spectrum reads M5e — 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 188378 in the constellation Sgr. At apparent magnitude 8.6, it is an easy target for binoculars.

Like any astronomical target, HD 188378 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 188378 is an epic variable star

HD 188378 scores 50 points on Spacedle's rarity scale, which places it in the epic tier. Another 28 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Toward the galactic centre, On the zodiac, Cool red M-type star, Red dwarf, Dramatic variable (over 2 magnitudes) 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.