About HD 162740
HD 162740 is a rare star. It sits in the constellation Sgr, shines at apparent magnitude 8.23 and has spectral type G0Ib/II.
Its spectrum reads G0Ib/II — a G-type star: the very same spectral class as our own Sun.
Rare star 40 EP
HD 162740
RA 268.3213° · Dec -17.4836° · star
Score breakdown
· 5 badgesRare 50 pts → Epic
- Supergiant +18
- Toward the galactic centre +8
- Sun-like G-type star +8
- Star +3
- On the zodiac +3
Total score 40
10 more points to reach Epic.
Badges
- Star · +3
- Toward the galactic centre · +8
- On the zodiac · +3
- Sun-like G-type star · +8
- Supergiant · +18
Trivia
Hard to believe
- True brightness. It pours out about 4.4 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 G0Ib/II — 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.
Find it in the sky
- How to spot it. At magnitude 8.2 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 1.3) — 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 4090 K, against the Sun's 5778 K.
Properties
- absmag
- -11.77
- bv
- 1.32
- constellation
- Sgr
- luminosity
- 4446312.6747
- mag
- 8.23
- name
- HD 162740
- spect
- G0Ib/II
How to see it
Look for HD 162740 in the constellation Sgr. At apparent magnitude 8.23, it is an easy target for binoculars.
Like any astronomical target, HD 162740 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 162740 is a rare star
HD 162740 scores 40 points on Spacedle's rarity scale, which places it in the rare tier. Another 10 points would lift it into a rarer tier.
That score comes from 5 science badges — Star, Toward the galactic centre, On the zodiac, Sun-like G-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.