About HR 6947
HR 6947 is an epic variable star. It sits in the constellation Sgr, shines at apparent magnitude 6.59 and has spectral type G1Ib.
Its spectrum reads G1Ib — a G-type star: the very same spectral class as our own Sun.
Epic variable star 55 EP
HR 6947
RA 277.9722° · Dec -19.1251° · star
Score breakdown
· 7 badgesEpic 78 pts → Anomaly
- Supergiant +18
- Strongly variable +10
- Toward the galactic centre +8
- Sun-like G-type star +8
- Variable star +5
- On the zodiac +3
- A named variable star +3
Total score 55
23 more points to reach Anomaly.
Badges
- Variable star · +5
- Toward the galactic centre · +8
- On the zodiac · +3
- Sun-like G-type star · +8
- Supergiant · +18
- Strongly variable · +10
- A named variable star · +3
Trivia
What it actually is
- Spectral class. Its spectrum reads G1Ib — 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 6.6 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagittarius.
- Southern sky. It rides the southern half of the sky — an easier target the further south you are.
- 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 1.1) — 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 4580 K, against the Sun's 5778 K.
Properties
- absmag
- -13.41
- bv
- 1.07
- constellation
- Sgr
- luminosity
- 20137242.4986
- mag
- 6.59
- name
- HR 6947
- spect
- G1Ib
- var amplitude
- 0.72
- var designation
- U
- var max
- 6.164
- var min
- 6.884
How to see it
Look for HR 6947 in the constellation Sgr. At apparent magnitude 6.59, it is an easy target for binoculars.
Like any astronomical target, HR 6947 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 6947 is an epic variable star
HR 6947 scores 55 points on Spacedle's rarity scale, which places it in the epic tier. Another 23 points would lift it into a rarer tier.
That score comes from 7 science badges — Variable star, Toward the galactic centre, On the zodiac, Sun-like G-type star, Supergiant, 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.