Common variable star 20 EP

HIP 25704

RA 82.3337° · Dec 43.4092° · star

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Score breakdown

· 4 badges

20 pts · Common

Common 22 pts → Uncommon

Deep red star +8
Variable star +5
Gently variable +4
A named variable star +3

Total score 20

2 more points to reach Uncommon.

Badges

Variable star · +5
Deep red star · +8
Gently variable · +4
A named variable star · +3

Trivia

Hard to believe

True brightness. It pours out about 937.6 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 N0v — 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 on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.
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 9.9 you'll want a small backyard telescope, 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 2.1) — one of the coolest surfaces a star can have while still fusing.

Properties

absmag: -10.1
bv: 2.1
constellation: Aur
luminosity: 954992.586
mag: 9.9
name: HIP 25704
spect: N0v
var amplitude: 0.23
var designation: CM
var max: 9.78
var min: 10.01

Nearby objects

About HIP 25704

HIP 25704 is a common variable star. It sits in the constellation Aur, shines at apparent magnitude 9.9 and has spectral type N0v.

Its spectrum reads N0v — a carbon star, wrapped in so much soot that its light is filtered to a deep ruby red.

How to see it

Look for HIP 25704 in the constellation Aur. At apparent magnitude 9.9, a small backyard telescope will bring it into view.

Like any astronomical target, HIP 25704 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 HIP 25704 is a common variable star

HIP 25704 scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.

That score comes from 4 science badges — Variable star, 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.