About HD 331970
HD 331970 is a rare variable star. It sits in the constellation Cyg, shines at apparent magnitude 9.47 and has spectral type G1Ibvar.
Its spectrum reads G1Ibvar — a G-type star: the very same spectral class as our own Sun.
Rare variable star 44 EP
HD 331970
RA 303.0951° · Dec 32.8716° · star
Score breakdown
· 5 badgesRare 50 pts → Epic
- Supergiant +18
- Strongly variable +10
- Sun-like G-type star +8
- Variable star +5
- A named variable star +3
Total score 44
6 more points to reach Epic.
Badges
- Variable star · +5
- Sun-like G-type star · +8
- Supergiant · +18
- Strongly variable · +10
- A named variable star · +3
Trivia
Hard to believe
- True brightness. It pours out about 1.4 million times as much light as the Sun. It only looks ordinary because it is so far away.
What it actually is
- Spectral class. Its spectrum reads G1Ibvar — 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 9.5 you'll want a small backyard telescope, over in Cygnus.
- 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 July — 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.
Properties
- absmag
- -10.53
- bv
- 1.247
- constellation
- Cyg
- luminosity
- 1419057.5217
- mag
- 9.47
- name
- HD 331970
- spect
- G1Ibvar
- var amplitude
- 0.66
- var designation
- MW
- var max
- 9.133
- var min
- 9.793
How to see it
Look for HD 331970 in the constellation Cyg. At apparent magnitude 9.47, a small backyard telescope will bring it into view.
Like any astronomical target, HD 331970 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 331970 is a rare variable star
HD 331970 scores 44 points on Spacedle's rarity scale, which places it in the rare tier. Another 6 points would lift it into a rarer tier.
That score comes from 5 science badges — Variable star, 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.