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Rare variable star 34 EP

HD 321021

RA 270.1364° · Dec -33.9155° · star

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Score breakdown

· 7 badges
34 pts · Rare
Rare 50 pts → Epic
  • Toward the galactic centre +8
  • Deep red star +8
  • Variable star +5
  • Gently variable +4
  • On the zodiac +3
  • Orange K-type star +3
  • A named variable star +3
Total score 34

16 more points to reach Epic.

Badges

  • Variable star · +5
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • Orange K-type star · +3
  • Deep red star · +8
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 2.4 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 K5 — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.
  • 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 8.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagittarius.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around June — 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 1.8) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3440 K, against the Sun's 5778 K.

Properties

absmag
-11.12
bv
1.764
constellation
Sgr
luminosity
2443430.5527
mag
8.88
name
HD 321021
spect
K5
var amplitude
0.1
var designation
V4377
var max
8.828
var min
8.928

About HD 321021

HD 321021 is a rare variable star. It sits in the constellation Sgr, shines at apparent magnitude 8.88 and has spectral type K5.

Its spectrum reads K5 — 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 HD 321021 in the constellation Sgr. At apparent magnitude 8.88, it is an easy target for binoculars.

Like any astronomical target, HD 321021 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 321021 is a rare variable star

HD 321021 scores 34 points on Spacedle's rarity scale, which places it in the rare tier. Another 16 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Toward the galactic centre, On the zodiac, Orange K-type 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.