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Common star 16 EP

HD 49290

RA 102.0686° · Dec 14.5924° · star

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Score breakdown

· 4 badges
16 pts · Common
Common 22 pts → Uncommon
  • White A-type star +5
  • Blue-white star +5
  • Star +3
  • On the zodiac +3
Total score 16

6 more points to reach Uncommon.

Badges

  • Star · +3
  • On the zodiac · +3
  • White A-type star · +5
  • Blue-white star · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads A0 — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

Find it in the sky

  • How to spot it. At magnitude 7.7 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Gemini.
  • 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 January — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out blue-white (B−V -0) — the hallmark of a surface far hotter than the Sun's.
  • 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 10740 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
-12.31
bv
-0.046
constellation
Gem
luminosity
7311390.8348
mag
7.69
name
HD 49290
spect
A0

About HD 49290

HD 49290 is a common star. It sits in the constellation Gem, shines at apparent magnitude 7.69 and has spectral type A0.

Its spectrum reads A0 — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for HD 49290 in the constellation Gem. At apparent magnitude 7.69, it is an easy target for binoculars.

Like any astronomical target, HD 49290 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 49290 is a common star

HD 49290 scores 16 points on Spacedle's rarity scale, which places it in the common tier. Another 6 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, On the zodiac, White A-type star and Blue-white 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.