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Uncommon star 25 EP

HD 102688

RA 177.3628° · Dec 18.2355° · star

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Score breakdown

· 5 badges
25 pts · Uncommon
Uncommon 34 pts → Rare
  • Deep red star +8
  • Red dwarf +6
  • Cool red M-type star +5
  • Star +3
  • On the zodiac +3
Total score 25

9 more points to reach Rare.

Badges

  • Star · +3
  • On the zodiac · +3
  • Cool red M-type star · +5
  • Deep red star · +8
  • Red dwarf · +6

Trivia

Hard to believe

  • True brightness. It pours out about 3.6 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 M... — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

Find it in the sky

  • How to spot it. At magnitude 8.4 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Leo.
  • 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 March — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out deep orange-red (B−V 1.5) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3730 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HD number is from the Henry Draper Catalogue, in which Annie Jump Cannon personally classified the spectra of nearly 400,000 stars — still the largest such feat by one person.

Properties

absmag
-11.55
bv
1.541
constellation
Leo
luminosity
3630780.5477
mag
8.45
name
HD 102688
spect
M...

Nearby objects

About HD 102688

HD 102688 is an uncommon star. It sits in the constellation Leo, shines at apparent magnitude 8.45 and has spectral type M....

Its spectrum reads M... — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

How to see it

Look for HD 102688 in the constellation Leo. At apparent magnitude 8.45, it is an easy target for binoculars.

Like any astronomical target, HD 102688 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 102688 is an uncommon star

HD 102688 scores 25 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 9 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, On the zodiac, Cool red M-type star, Deep red star and Red dwarf — 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.