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Common star 20 EP

HD 137505

RA 232.4525° · Dec -63.2672° · star

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Score breakdown

· 4 badges
20 pts · Common
Common 22 pts → Uncommon
  • Deep red star +8
  • Giant star +6
  • Star +3
  • Orange K-type star +3
Total score 20

2 more points to reach Uncommon.

Badges

  • Star · +3
  • Orange K-type star · +3
  • Giant star · +6
  • Deep red star · +8

Trivia

Hard to believe

  • True brightness. It pours out about 2.9 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 K2/K3III: — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.

Find it in the sky

  • How to spot it. At magnitude 8.7 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Triangulum Australe.
  • 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 1.5) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3840 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HD number is from the Henry Draper Catalogue, in which Annie Jump Cannon personally classified the spectra of nearly 400,000 stars — still the largest such feat by one person.

Properties

absmag
-11.33
bv
1.47
constellation
TrA
luminosity
2964831.3895
mag
8.67
name
HD 137505
spect
K2/K3III:

Nearby objects

About HD 137505

HD 137505 is a common star. It sits in the constellation TrA, shines at apparent magnitude 8.67 and has spectral type K2/K3III:.

Its spectrum reads K2/K3III: — 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 137505 in the constellation TrA. At apparent magnitude 8.67, it is an easy target for binoculars.

Like any astronomical target, HD 137505 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 137505 is a common star

HD 137505 scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, Orange K-type star, Giant star 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.