About HR 6661
HR 6661 is an epic variable star. It sits in the constellation Oph, shines at apparent magnitude 6.18 and has spectral type G3Ibv SB.
Its spectrum reads G3Ibv SB — a G-type star: the very same spectral class as our own Sun.
Epic variable star 54 EP
HR 6661
RA 268.1613° · Dec -6.1436° · star
Score breakdown
· 6 badgesEpic 78 pts → Anomaly
- Supergiant +18
- Fades out of naked-eye view +16
- Sun-like G-type star +8
- Variable star +5
- Gently variable +4
- A named variable star +3
Total score 54
24 more points to reach Anomaly.
Badges
- Variable star · +5
- Sun-like G-type star · +8
- Supergiant · +18
- Gently variable · +4
- Fades out of naked-eye view · +16
- A named variable star · +3
Trivia
What it actually is
- Spectral class. Its spectrum reads G3Ibv SB — a G-type star: the very same spectral class as our own Sun.
- Where it is in life. It is a supergiant, hundreds of times wider than the Sun.
- 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 6.2 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Ophiuchus.
- Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
- Best time of year. It stands highest in the middle of the night around June — that's when to go looking.
Its true colour
- Its true colour. Measured through blue and visual filters it comes out orange (B−V 1.2) — 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 4210 K, against the Sun's 5778 K.
Properties
- absmag
- -13.82
- bv
- 1.25
- constellation
- Oph
- luminosity
- 29376496.5196
- mag
- 6.18
- name
- HR 6661
- spect
- G3Ibv SB
- var amplitude
- 0.48
- var designation
- Y
- var max
- 5.941
- var min
- 6.421
How to see it
Look for HR 6661 in the constellation Oph. At apparent magnitude 6.18, it is an easy target for binoculars.
Like any astronomical target, HR 6661 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 6661 is an epic variable star
HR 6661 scores 54 points on Spacedle's rarity scale, which places it in the epic tier. Another 24 points would lift it into a rarer tier.
That score comes from 6 science badges — Variable star, Sun-like G-type star, Supergiant, Gently variable, Fades out of naked-eye view 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.