← Back to dex
Rare variable star 41 EP

HD 1613

RA 5.1815° · Dec 61.8796° · star

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 7 badges
41 pts · Rare
Rare 50 pts → Epic
  • Bright giant +12
  • Deep red star +8
  • Variable star +5
  • Cool red M-type star +5
  • Never sets (northern circumpolar) +4
  • Gently variable +4
  • A named variable star +3
Total score 41

9 more points to reach Epic.

Badges

  • Variable star · +5
  • Never sets (northern circumpolar) · +4
  • Cool red M-type star · +5
  • 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 M2II: — 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 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 6.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cassiopeia.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • Best time of year. It stands highest in the middle of the night around September — 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) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3150 K, against the Sun's 5778 K.

Properties

absmag
-13.2
bv
2.02
constellation
Cas
luminosity
16595869.0744
mag
6.8
name
HD 1613
spect
M2II:
var amplitude
0.1
var designation
V743
var max
6.757
var min
6.857

About HD 1613

HD 1613 is a rare variable star. It sits in the constellation Cas, shines at apparent magnitude 6.8 and has spectral type M2II:.

Its spectrum reads M2II: — 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 HD 1613 in the constellation Cas. At apparent magnitude 6.8, it is an easy target for binoculars.

Like any astronomical target, HD 1613 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 1613 is a rare variable star

HD 1613 scores 41 points on Spacedle's rarity scale, which places it in the rare tier. Another 9 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Never sets (northern circumpolar), Cool red M-type star, 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.