Pulsar
PSR J1921+1216_P
Millisecond pulsar · binary system
A millisecond pulsar spinning 333 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 8.417 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 | Aquila |
| Period | 3.000 ms (333 Hz) |
| Dispersion measure | 256.1 pc/cm³ |
| Distance | 6,851 pc (22.3 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.24 M☉ |
| Orbital period | 8.417 days |
| Discovery | 2025 · fast_gpps |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 19h 21m 03.3s |
| Declination (J2000) | +12° 16′ 00″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 78° S. North of latitude 78° N it never sets. It stands highest at midnight in July, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 22 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 396 million years.