About HIP 81664
HIP 81664 is a trash star. It sits in the constellation UMi and shines at apparent magnitude 10.55.
Its colour puts the surface at roughly 4590 K, against the Sun's 5778 K.
Trash star 7 EP
HIP 81664
RA 250.2388° · Dec 82.3614° · star
Score breakdown
· 2 badgesTrash 15 pts → Common
- Never sets (northern circumpolar) +4
- Star +3
Total score 7
8 more points to reach Common.
Badges
- Star · +3
- Never sets (northern circumpolar) · +4
Trivia
Hard to believe
- True brightness. It pours out about 515.2 thousand times as much light as the Sun. It only looks ordinary because it is so far away.
Find it in the sky
- How to spot it. At magnitude 10.6 you'll want a small backyard telescope, over in Ursa Minor.
- Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
- Best time of year. It stands highest in the middle of the night around May — that's when to go looking.
Its true colour
- Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.1) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.
By the numbers
- Surface temperature. Its colour puts the surface at roughly 4590 K, against the Sun's 5778 K.
What's in a name
- Its catalogue. The HIP number comes from Hipparcos, the ESA satellite that between 1989 and 1993 pinned down 118,000 stars precisely enough to triangulate their distances.
Properties
- absmag
- -9.45
- bv
- 1.066
- constellation
- UMi
- luminosity
- 524807.4602
- mag
- 10.55
- name
- HIP 81664
How to see it
Look for HIP 81664 in the constellation UMi. At apparent magnitude 10.55, a small backyard telescope will bring it into view.
Like any astronomical target, HIP 81664 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 HIP 81664 is a trash star
HIP 81664 scores 7 points on Spacedle's rarity scale, which places it in the trash tier. Another 8 points would lift it into a rarer tier.
That score comes from 2 science badges — Star and Never sets (northern circumpolar) — 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.