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Uncommon variable star 23 EP

HD 39340

RA 88.2754° · Dec 26.4454° · star

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Score breakdown

· 6 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Hot blue B-type star +6
  • Variable star +5
  • Gently variable +4
  • On the zodiac +3
  • A named variable star +3
  • Main-sequence star +2
Total score 23

11 more points to reach Rare.

Badges

  • Variable star · +5
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Main-sequence star · +2
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 4.9 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 B3V — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
  • 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 8.1 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Taurus.
  • 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 brilliant white (B−V 0.1) — hotter and whiter than the Sun, the colour of Sirius or Vega.

Properties

absmag
-11.89
bv
0.05
constellation
Tau
luminosity
4965923.2145
mag
8.11
name
HD 39340
spect
B3V
var amplitude
0.12
var designation
V593
var max
8.068
var min
8.188

About HD 39340

HD 39340 is an uncommon variable star. It sits in the constellation Tau, shines at apparent magnitude 8.11 and has spectral type B3V.

Its spectrum reads B3V — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for HD 39340 in the constellation Tau. At apparent magnitude 8.11, it is an easy target for binoculars.

Like any astronomical target, HD 39340 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 39340 is an uncommon variable star

HD 39340 scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, On the zodiac, Hot blue B-type star, Main-sequence 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.