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Uncommon star 22 EP

HR 2858

RA 112.1969° · Dec 15.1098° · star

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Score breakdown

· 5 badges
22 pts · Uncommon
Uncommon 34 pts → Rare
  • Hot blue B-type star +6
  • Subgiant (leaving the main sequence) +5
  • Blue-white star +5
  • Star +3
  • On the zodiac +3
Total score 22

12 more points to reach Rare.

Badges

  • Star · +3
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Subgiant (leaving the main sequence) · +5
  • Blue-white star · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads B9IV — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
  • Where it is in life. It is a subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.

Sense of scale

  • In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 6.2 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.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Getting there

  • Aboard Voyager 1. ≈ 12.9 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-0.528
bv
-0.04
constellation
Gem
dist ly
732.9348
luminosity
141.6446
mag
6.23
name
HR 2858
spect
B9IV

About HR 2858

HR 2858 is an uncommon star. It lies about 732.9 light-years from Earth, sits in the constellation Gem, shines at apparent magnitude 6.23 and has spectral type B9IV.

Its spectrum reads B9IV — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for HR 2858 in the constellation Gem. At apparent magnitude 6.23, it is an easy target for binoculars.

Like any astronomical target, HR 2858 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 HR 2858 is an uncommon star

HR 2858 scores 22 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 12 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, On the zodiac, Hot blue B-type star, Subgiant (leaving the main sequence) 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.