About HD 2973
HD 2973 is a common star. It sits in the constellation Cas, shines at apparent magnitude 10.34 and has spectral type G5.
Its spectrum reads G5 — a G-type star: the very same spectral class as our own Sun.
Common star 15 EP
HD 2973
RA 8.4153° · Dec 62.7924° · star
Score breakdown
· 3 badgesCommon 22 pts → Uncommon
- Sun-like G-type star +8
- Never sets (northern circumpolar) +4
- Star +3
Total score 15
7 more points to reach Uncommon.
Badges
- Star · +3
- Never sets (northern circumpolar) · +4
- Sun-like G-type star · +8
Trivia
Hard to believe
- True brightness. It pours out about 625.2 thousand 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 G5 — a G-type star: the very same spectral class as our own Sun.
Find it in the sky
- How to spot it. At magnitude 10.3 you'll want a small backyard telescope, 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 brilliant white (B−V 0.2) — hotter and whiter than the Sun, the colour of Sirius or Vega.
- Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.
By the numbers
- Surface temperature. Its colour puts the surface at roughly 8270 K, against the Sun's 5778 K.
Properties
- absmag
- -9.66
- bv
- 0.186
- constellation
- Cas
- luminosity
- 636795.5209
- mag
- 10.34
- name
- HD 2973
- spect
- G5
How to see it
Look for HD 2973 in the constellation Cas. At apparent magnitude 10.34, a small backyard telescope will bring it into view.
Like any astronomical target, HD 2973 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 2973 is a common star
HD 2973 scores 15 points on Spacedle's rarity scale, which places it in the common tier. Another 7 points would lift it into a rarer tier.
That score comes from 3 science badges — Star, Never sets (northern circumpolar) and Sun-like G-type 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.