← Back to dex
Uncommon pulsar 30 EP

J2021+3651

RA 305.2727° · Dec 36.8513° · pulsar

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 2 badges
30 pts · Uncommon
Uncommon 34 pts → Rare
  • Pulsar +22
  • Deeply embedded (high DM) +8
Total score 30

4 more points to reach Rare.

Badges

  • Pulsar · +22
  • Deeply embedded (high DM) · +8

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 368 — 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 July — 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 whirls around 9.6 times every second, and it has kept that beat to better than a millionth of a second.

Properties

bsurf
3188809122000
dm
367.5
name
J2021+3651
period ms
103.741

Nearby objects

About J2021+3651

J2021+3651 is an uncommon pulsar. It spins once every 103.741 ms, has a dispersion measure of 367.5 pc cm⁻³ and carries a surface magnetic field around 3.19×10^12 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, J2021+3651 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 J2021+3651 is an uncommon pulsar

J2021+3651 scores 30 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 4 points would lift it into a rarer tier.

That score comes from 2 science badges — Pulsar and Deeply embedded (high DM) — 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.