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Epic variable star 64 EP

HR 2405

RA 99.1368° · Dec 38.4455° · star

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Score breakdown

· 7 badges
64 pts · Epic
Epic 78 pts → Anomaly
  • Carbon star (sooty red) +24
  • Bright giant +12
  • Naked-eye visible +8
  • Deep red star +8
  • Variable star +5
  • Gently variable +4
  • A named variable star +3
Total score 64

14 more points to reach Anomaly.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Carbon star (sooty red) · +24
  • Bright giant · +12
  • Deep red star · +8
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads C5II — a carbon star, wrapped in so much soot that its light is filtered to a deep ruby red.
  • Where it is in life. It is a bright giant, well on its way to the largest stars there are.
  • 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 5.4 you can see it with your own eyes from a dark site, over in Auriga.
  • 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 December — 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 2.8) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 2530 K, against the Sun's 5778 K.

Properties

absmag
-14.6
bv
2.773
constellation
Aur
luminosity
60255958.6074
mag
5.4
name
HR 2405
spect
C5II
var amplitude
0.48
var designation
UU
var max
5.212
var min
5.692

About HR 2405

HR 2405 is an epic variable star. It sits in the constellation Aur, shines at apparent magnitude 5.4 and has spectral type C5II.

Its spectrum reads C5II — a carbon star, wrapped in so much soot that its light is filtered to a deep ruby red.

How to see it

Look for HR 2405 in the constellation Aur. At apparent magnitude 5.4, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HR 2405 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 2405 is an epic variable star

HR 2405 scores 64 points on Spacedle's rarity scale, which places it in the epic tier. Another 14 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Naked-eye visible, Carbon star (sooty red), Bright giant, Deep red star, 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.