Pulsar
PSR J1821+0007_P
Millisecond pulsar · binary system
A millisecond pulsar spinning 237 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 8.000 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 | Ophiuchus |
| Period | 4.220 ms (237 Hz) |
| Dispersion measure | 55.2 pc/cm³ |
| Distance | 1,863 pc (6.1 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.22 M☉ |
| Orbital period | 8.000 days |
| Discovery | 2025 · fast_gpps |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 18h 21m 02.9s |
| Declination (J2000) | +0° 07′ 00″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 90° N. 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 6,076 years ago. At that time the first farming villages were being founded; there was no writing yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 108 million years.