About HD 187820
HD 187820 is an uncommon variable star. It sits in the constellation Aql, shines at apparent magnitude 7.8 and has spectral type G5.
Its spectrum reads G5 — a G-type star: the very same spectral class as our own Sun.
Uncommon variable star 26 EP
HD 187820
RA 298.0875° · Dec -11.3669° · star
Score breakdown
· 4 badgesUncommon 34 pts → Rare
- Strongly variable +10
- Sun-like G-type star +8
- Variable star +5
- A named variable star +3
Total score 26
8 more points to reach Rare.
Badges
- Variable star · +5
- Sun-like G-type star · +8
- Strongly variable · +10
- A named variable star · +3
Trivia
What it actually is
- Spectral class. Its spectrum reads G5 — a G-type star: the very same spectral class as our own 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 7.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Aquila.
- 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 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 0.9) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.
- 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 4950 K, against the Sun's 5778 K.
Properties
- absmag
- -12.2
- bv
- 0.918
- constellation
- Aql
- luminosity
- 6606934.4801
- mag
- 7.8
- name
- HD 187820
- spect
- G5
- var amplitude
- 0.53
- var designation
- V1162
- var max
- 7.466
- var min
- 7.996
How to see it
Look for HD 187820 in the constellation Aql. At apparent magnitude 7.8, it is an easy target for binoculars.
Like any astronomical target, HD 187820 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 187820 is an uncommon variable star
HD 187820 scores 26 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 8 points would lift it into a rarer tier.
That score comes from 4 science badges — Variable star, Sun-like G-type star, 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.