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Rare pulsar 42 EP

J1638-4725

RA 249.5539° · Dec -47.4256° · pulsar

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Score breakdown

· 3 badges
42 pts · Rare
Rare 50 pts → Epic
  • Pulsar +22
  • Binary pulsar +12
  • Deeply embedded (high DM) +8
Total score 42

8 more points to reach Epic.

Badges

  • Pulsar · +22
  • Binary pulsar · +12
  • 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 552 — 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.
  • It has a partner. It orbits a companion star, and because its pulses are such a precise clock the orbit can be traced to extraordinary accuracy. A binary pulsar is how gravitational waves were first proven to be real, decades before one was directly detected.

Find it in the sky

  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around May — 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.

Properties

binary
yes
bsurf
1934818443000
dm
552.1
name
J1638-4725
period ms
763.9335

Nearby objects

About J1638-4725

J1638-4725 is a rare pulsar. It spins once every 763.933 ms, has a dispersion measure of 552.1 pc cm⁻³ and carries a surface magnetic field around 1.93×10^12 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, J1638-4725 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 J1638-4725 is a rare pulsar

J1638-4725 scores 42 points on Spacedle's rarity scale, which places it in the rare tier. Another 8 points would lift it into a rarer tier.

That score comes from 3 science badges — Pulsar, Binary 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.