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Uncommon star 24 EP

HD 128109

RA 218.5628° · Dec 29.3686° · star

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Score breakdown

· 3 badges
24 pts · Uncommon
Uncommon 34 pts → Rare
  • Supergiant +18
  • Star +3
  • Orange K-type star +3
Total score 24

10 more points to reach Rare.

Badges

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

Trivia

Hard to believe

  • True brightness. It pours out about 2.2 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 K2Ib-II: — 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 8.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Boötes.
  • 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 April — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.1) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 4550 K, against the Sun's 5778 K.

Properties

absmag
-11.05
bv
1.086
constellation
Boo
luminosity
2290867.6528
mag
8.95
name
HD 128109
spect
K2Ib-II:

Nearby objects

About HD 128109

HD 128109 is an uncommon star. It sits in the constellation Boo, shines at apparent magnitude 8.95 and has spectral type K2Ib-II:.

Its spectrum reads K2Ib-II: — 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 128109 in the constellation Boo. At apparent magnitude 8.95, it is an easy target for binoculars.

Like any astronomical target, HD 128109 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 128109 is an uncommon star

HD 128109 scores 24 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 10 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Orange K-type star and Supergiant — 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.