About HD 290931
HD 290931 is a trash star. It sits in the constellation Ori, shines at apparent magnitude 9.65 and has spectral type F0.
Its spectrum reads F0 — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Trash star 12 EP
HD 290931
RA 88.2362° · Dec -1.8444° · star
Score breakdown
· 3 badgesTrash 15 pts → Common
- In Orion's hunting ground +6
- Star +3
- Yellow-white F-type star +3
Total score 12
3 more points to reach Common.
Badges
- Star · +3
- In Orion's hunting ground · +6
- Yellow-white F-type star · +3
Trivia
Hard to believe
- True brightness. It pours out about 1.2 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 F0 — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Find it in the sky
- How to spot it. At magnitude 9.7 you'll want a small backyard telescope, over in Orion.
- Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
- Best time of year. It stands highest in the middle of the night around December — that's when to go looking.
Its true colour
- Its true colour. Measured through blue and visual filters it comes out yellow-white (B−V 0.4) — a shade brighter and crisper than our own Sun.
- 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 6930 K, against the Sun's 5778 K.
Properties
- absmag
- -10.35
- bv
- 0.391
- constellation
- Ori
- luminosity
- 1202264.4346
- mag
- 9.65
- name
- HD 290931
- spect
- F0
How to see it
Look for HD 290931 in the constellation Ori. At apparent magnitude 9.65, a small backyard telescope will bring it into view.
Like any astronomical target, HD 290931 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 290931 is a trash star
HD 290931 scores 12 points on Spacedle's rarity scale, which places it in the trash tier. Another 3 points would lift it into a rarer tier.
That score comes from 3 science badges — Star, In Orion's hunting ground and Yellow-white F-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.