About HD 38109
HD 38109 is a common star. It sits in the constellation Ori, shines at apparent magnitude 9.46 and has spectral type F2IVs.
Its spectrum reads F2IVs — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Common star 17 EP
HD 38109
RA 85.7718° · Dec -5.8076° · star
Score breakdown
· 4 badgesCommon 22 pts → Uncommon
- In Orion's hunting ground +6
- Subgiant (leaving the main sequence) +5
- Star +3
- Yellow-white F-type star +3
Total score 17
5 more points to reach Uncommon.
Badges
- Star · +3
- In Orion's hunting ground · +6
- Yellow-white F-type star · +3
- Subgiant (leaving the main sequence) · +5
Trivia
Hard to believe
- True brightness. It pours out about 1.4 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 F2IVs — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
- Where it is in life. It is a subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.
Find it in the sky
- How to spot it. At magnitude 9.5 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 0.3) — 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.
Properties
- absmag
- -10.54
- bv
- 0.332
- constellation
- Ori
- luminosity
- 1432187.8993
- mag
- 9.46
- name
- HD 38109
- spect
- F2IVs
How to see it
Look for HD 38109 in the constellation Ori. At apparent magnitude 9.46, a small backyard telescope will bring it into view.
Like any astronomical target, HD 38109 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 38109 is a common star
HD 38109 scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.
That score comes from 4 science badges — Star, In Orion's hunting ground, Yellow-white F-type star and Subgiant (leaving the main sequence) — 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.