← Back to dex
Uncommon star 32 EP

HR 5645

RA 228.2543° · Dec -61.7438° · star

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

Computing the sky for your location…

Score breakdown

· 4 badges
32 pts · Uncommon
Uncommon 34 pts → Rare
  • Supergiant +18
  • Deep red star +8
  • Star +3
  • Orange K-type star +3
Total score 32

2 more points to reach Rare.

Badges

  • Star · +3
  • Orange K-type star · +3
  • Supergiant · +18
  • Deep red star · +8

Trivia

What it actually is

  • Spectral class. Its spectrum reads K4Ib — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.
  • Where it is in life. It is a supergiant, hundreds of times wider than the Sun.

Find it in the sky

  • How to spot it. At magnitude 6.3 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Circinus.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around May — 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 1.9) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3280 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HR number is from the Bright Star Catalogue — roughly 9,100 stars, essentially everything the unaided eye can see.

Properties

absmag
-13.73
bv
1.901
constellation
Cir
luminosity
27039583.6411
mag
6.27
name
HR 5645
spect
K4Ib

About HR 5645

HR 5645 is an uncommon star. It sits in the constellation Cir, shines at apparent magnitude 6.27 and has spectral type K4Ib.

Its spectrum reads K4Ib — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.

How to see it

Look for HR 5645 in the constellation Cir. At apparent magnitude 6.27, it is an easy target for binoculars.

Like any astronomical target, HR 5645 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 5645 is an uncommon star

HR 5645 scores 32 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 2 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, Orange K-type star, Supergiant and Deep red 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.