Pulsar
PSR J1821+0044_P
Millisecond pulsar · binary system
A millisecond pulsar spinning 369 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 2.316 days orbit with a helium white dwarf. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Serpens |
| Period | 2.710 ms (369 Hz) |
| Dispersion measure | 126.9 pc/cm³ |
| Distance | 7,227 pc (23.6 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.16 M☉ |
| Orbital period | 2.316 days |
| Discovery | 2025 · fast_gpps |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 18h 21m 31.7s |
| Declination (J2000) | +0° 43′ 59″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 89° S. It stands highest at midnight in June, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 24 thousand years ago. At that time Homo sapiens was spreading out of Africa; there was no farming yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 418 million years.