About HR 5621
HR 5621 is an uncommon star. It sits in the constellation TrA, shines at apparent magnitude 5.76 and has spectral type F8Iab-Ib.
Its spectrum reads F8Iab-Ib — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Uncommon star 32 EP
HR 5621
RA 227.3747° · Dec -67.0841° · star
Score breakdown
· 4 badgesUncommon 34 pts → Rare
- Supergiant +18
- Naked-eye visible +8
- Star +3
- Yellow-white F-type star +3
Total score 32
2 more points to reach Rare.
Badges
- Star · +3
- Naked-eye visible · +8
- Yellow-white F-type star · +3
- Supergiant · +18
Trivia
What it actually is
- Spectral class. Its spectrum reads F8Iab-Ib — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
- Where it is in life. It is a supergiant. Drop it where the Sun is and its surface would engulf the inner planets.
Find it in the sky
- How to spot it. At magnitude 5.8 you can see it with your own eyes from a dark site, over in Triangulum Australe.
- Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
- 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 yellow (B−V 0.7) — 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 5690 K, against the Sun's 5778 K.
Properties
- absmag
- -14.24
- bv
- 0.675
- constellation
- TrA
- luminosity
- 43251383.1035
- mag
- 5.76
- name
- HR 5621
- spect
- F8Iab-Ib
How to see it
Look for HR 5621 in the constellation TrA. At apparent magnitude 5.76, it can be glimpsed with the unaided eye under dark skies.
Like any astronomical target, HR 5621 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 5621 is an uncommon star
HR 5621 scores 32 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 2 points would lift it into a rarer tier.
That score comes from 4 science badges — Star, Naked-eye visible, 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.