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Common variable star 17 EP

HD 30245

RA 71.9296° · Dec 40.2325° · star

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Score breakdown

· 4 badges
17 pts · Common
Common 22 pts → Uncommon
  • Variable star +5
  • White A-type star +5
  • Gently variable +4
  • A named variable star +3
Total score 17

5 more points to reach Uncommon.

Badges

  • Variable star · +5
  • White A-type star · +5
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 2.9 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 A — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.
  • 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 8.7 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Perseus.
  • 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 yellow-white (B−V 0.3) — a shade brighter and crisper than our own Sun.
  • Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

Properties

absmag
-11.33
bv
0.31
constellation
Per
luminosity
2964831.3895
mag
8.67
name
HD 30245
spect
A
var amplitude
0.2
var designation
V593
var max
8.591
var min
8.791

Nearby objects

About HD 30245

HD 30245 is a common variable star. It sits in the constellation Per, shines at apparent magnitude 8.67 and has spectral type A.

Its spectrum reads A — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for HD 30245 in the constellation Per. At apparent magnitude 8.67, it is an easy target for binoculars.

Like any astronomical target, HD 30245 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 30245 is a common variable star

HD 30245 scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.

That score comes from 4 science badges — Variable star, White A-type 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.