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Epic variable star 50 EP

HR 5101

RA 203.2505° · Dec -7.1947° · star

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Score breakdown

· 7 badges
50 pts · Epic
Epic 78 pts → Anomaly
  • Dramatic variable (over 2 magnitudes) +20
  • Deep red star +8
  • Giant star +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
  • On the zodiac · +3
  • Cool red M-type star · +5
  • Giant star · +6
  • Deep red star · +8
  • Dramatic variable (over 2 magnitudes) · +20
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 487.5 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 M6IIIe-M9.5e — 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 10.6 you'll want a small backyard telescope, over in Virgo.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around April — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out deep orange-red (B−V 1.5) — one of the coolest surfaces a star can have while still fusing.

Properties

absmag
-9.39
bv
1.5
constellation
Vir
luminosity
496592.3215
mag
10.61
name
HR 5101
spect
M6IIIe-M9.5e
var amplitude
4.33
var designation
S
var max
7.279
var min
11.609

About HR 5101

HR 5101 is an epic variable star. It sits in the constellation Vir, shines at apparent magnitude 10.61 and has spectral type M6IIIe-M9.5e.

Its spectrum reads M6IIIe-M9.5e — 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 HR 5101 in the constellation Vir. At apparent magnitude 10.61, a small backyard telescope will bring it into view.

Like any astronomical target, HR 5101 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 HR 5101 is an epic variable star

HR 5101 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, On the zodiac, Cool red M-type star, Giant star, Deep red star, 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.