About HD 2207
HD 2207 is a rare variable star. It sits in the constellation Cas, shines at apparent magnitude 7.8 and has spectral type F5IIvar.
Its spectrum reads F5IIvar — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Rare variable star 37 EP
HD 2207
RA 6.5810° · Dec 51.2804° · star
Score breakdown
· 6 badgesRare 50 pts → Epic
- Bright giant +12
- Strongly variable +10
- Variable star +5
- Never sets (northern circumpolar) +4
- Yellow-white F-type star +3
- A named variable star +3
Total score 37
13 more points to reach Epic.
Badges
- Variable star · +5
- Never sets (northern circumpolar) · +4
- Yellow-white F-type star · +3
- Bright giant · +12
- Strongly variable · +10
- A named variable star · +3
Trivia
What it actually is
- Spectral class. Its spectrum reads F5IIvar — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
- Where it is in life. It is a bright giant, well on its way to the largest stars there are.
- It changes. This star does not hold still: its brightness rises and falls on a rhythm of hours, days or years, either pulsing in size or being eclipsed by a companion.
Find it in the sky
- How to spot it. At magnitude 7.8 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.
Properties
- absmag
- -12.2
- bv
- 0.635
- constellation
- Cas
- luminosity
- 6606934.4801
- mag
- 7.8
- name
- HD 2207
- spect
- F5IIvar
- var amplitude
- 0.81
- var designation
- TU
- var max
- 7.168
- var min
- 7.978
How to see it
Look for HD 2207 in the constellation Cas. At apparent magnitude 7.8, it is an easy target for binoculars.
Like any astronomical target, HD 2207 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 2207 is a rare variable star
HD 2207 scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.
That score comes from 6 science badges — Variable star, Never sets (northern circumpolar), Yellow-white F-type star, Bright giant, Strongly variable and A named variable 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.