About HR 2785
HR 2785 is an uncommon star. It sits in the constellation CMa, shines at apparent magnitude 6.06 and has spectral type F2Ia.
Its spectrum reads F2Ia — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Uncommon star 24 EP
HR 2785
RA 109.7580° · Dec -19.2803° · star
Score breakdown
· 3 badgesUncommon 34 pts → Rare
- Supergiant +18
- Star +3
- Yellow-white F-type star +3
Total score 24
10 more points to reach Rare.
Badges
- Star · +3
- Yellow-white F-type star · +3
- Supergiant · +18
Trivia
What it actually is
- Spectral class. Its spectrum reads F2Ia — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
- Where it is in life. It is a luminous supergiant — among the largest and rarest stars in the galaxy.
Find it in the sky
- How to spot it. At magnitude 6.1 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Canis Major.
- Southern sky. It rides the southern half of the sky — an easier target the further south you are.
- Best time of year. It stands highest in the middle of the night around January — that's when to go looking.
Its true colour
- Its true colour. Measured through blue and visual filters it comes out yellow (B−V 0.6) — almost exactly the Sun's own shade — a stellar twin in colour, if not in size.
- 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 5920 K, against the Sun's 5778 K.
Properties
- absmag
- -13.94
- bv
- 0.612
- constellation
- CMa
- luminosity
- 32809529.3113
- mag
- 6.06
- name
- HR 2785
- spect
- F2Ia
How to see it
Look for HR 2785 in the constellation CMa. At apparent magnitude 6.06, it is an easy target for binoculars.
Like any astronomical target, HR 2785 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 HR 2785 is an uncommon star
HR 2785 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, Yellow-white F-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.