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Uncommon pulsar 22 EP

J1821+4147

RA 275.4681° · Dec 41.7840° · pulsar

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Score breakdown

· 1 badge
22 pts · Uncommon
Uncommon 34 pts → Rare
  • Pulsar +22
Total score 22

12 more points to reach Rare.

Badges

  • Pulsar · +22

Trivia

Handle with care

  • Its gravity. Surface gravity is around 190 billion times Earth's. A fall of one metre would end at roughly a tenth of the speed of light.

What it actually is

  • What it is. The collapsed core of a star that exploded: about one and a half Suns of matter crushed into a ball the size of a city, held up only by the refusal of neutrons to be squeezed further.
  • Reading the fog. Its dispersion measure is 40.7 — a count of the free electrons in every column of space between here and there. Those electrons slow the low-frequency pulses more than the high ones, and that lag is how its distance is worked out.

Find it in the sky

  • 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 June — that's when to go looking.

Standing on it

  • Why we can see it. We only know about it because its beam happens to sweep across the Earth. Most of the galaxy's pulsars are pointing somewhere else and are invisible to us.

By the numbers

  • Density. A sugar-cube of its core would weigh about a billion tonnes — as much as every car on Earth put together.
  • Spin. It turns once every 1.26 seconds, and holds that beat to better than a millionth of a second.

Properties

bsurf
1494790093000
dm
40.673
name
J1821+4147
period ms
1261.8572

Nearby objects

About J1821+4147

J1821+4147 is an uncommon pulsar. It spins once every 1,261.857 ms, has a dispersion measure of 40.67 pc cm⁻³ and carries a surface magnetic field around 1.49×10^12 G.

The collapsed core of a star that exploded: about one and a half Suns of matter crushed into a ball the size of a city, held up only by the refusal of neutrons to be squeezed further.

How to see it

Like any astronomical target, J1821+4147 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 J1821+4147 is an uncommon pulsar

J1821+4147 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 1 science badge — Pulsar — 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.