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Epic variable star 50 EP

Eta Sgr

RA 274.4069° · Dec -36.7617° · star

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Score breakdown

· 9 badges
50 pts · Epic
Epic 78 pts → Anomaly
  • Naked-eye visible +8
  • Toward the galactic centre +8
  • Deep red star +8
  • Giant star +6
  • Variable star +5
  • Cool red M-type star +5
  • Gently variable +4
  • On the zodiac +3
  • A named variable star +3
Total score 50

28 more points to reach Anomaly.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • Cool red M-type star · +5
  • Giant star · +6
  • Deep red star · +8
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M2III — 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.

Sense of scale

  • In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 3.1 you can see it with your own eyes from a dark site, 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 June — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Properties

absmag
-0.154
bv
1.582
constellation
Sgr
dist ly
145.931
luminosity
100.3691
mag
3.1
name
Eta Sgr
spect
M2III
var amplitude
0.05
var designation
Eta
var max
3.069
var min
3.119

About Eta Sgr

Eta Sgr is an epic variable star. It lies about 145.9 light-years from Earth, sits in the constellation Sgr, shines at apparent magnitude 3.1 and has spectral type M2III.

Its spectrum reads M2III — 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 Eta Sgr in the constellation Sgr. At apparent magnitude 3.1, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, Eta Sgr 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 Eta Sgr is an epic variable star

Eta Sgr 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 9 science badges — Variable star, Naked-eye visible, Toward the galactic centre, On the zodiac, Cool red M-type star, Giant star, Deep red star and Gently variable — 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.