About HD 725
HD 725 is an uncommon star. It sits in the constellation Cas, shines at apparent magnitude 7.06 and has spectral type F5Ib-II.
Its spectrum reads F5Ib-II — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Uncommon star 28 EP
HD 725
RA 2.9364° · Dec 57.2715° · star
Score breakdown
· 4 badgesUncommon 34 pts → Rare
- Supergiant +18
- Never sets (northern circumpolar) +4
- Star +3
- Yellow-white F-type star +3
Total score 28
6 more points to reach Rare.
Badges
- Star · +3
- Never sets (northern circumpolar) · +4
- Yellow-white F-type star · +3
- Supergiant · +18
Trivia
What it actually is
- Spectral class. Its spectrum reads F5Ib-II — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
- Where it is in life. It is a supergiant, hundreds of times wider than the Sun.
Find it in the sky
- How to spot it. At magnitude 7.1 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cassiopeia.
- Northern sky. It rides the northern half of the sky — an easier target the further north you are.
- 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 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 5850 K, against the Sun's 5778 K.
Properties
- absmag
- -12.94
- bv
- 0.63
- constellation
- Cas
- luminosity
- 13061708.8813
- mag
- 7.06
- name
- HD 725
- spect
- F5Ib-II
How to see it
Look for HD 725 in the constellation Cas. At apparent magnitude 7.06, it is an easy target for binoculars.
Like any astronomical target, HD 725 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 725 is an uncommon star
HD 725 scores 28 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 6 points would lift it into a rarer tier.
That score comes from 4 science badges — Star, Never sets (northern circumpolar), 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.