Pulsar
PSR J1939+1848_P
Millisecond pulsar · binary system
A millisecond pulsar spinning 298 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 11.988 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 | Sagitta |
| Period | 3.360 ms (298 Hz) |
| Dispersion measure | 79.3 pc/cm³ |
| Distance | 2,820 pc (9.2 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.34 M☉ |
| Orbital period | 11.988 days |
| Discovery | 2025 · fast_gpps |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 19h 39m 01.5s |
| Declination (J2000) | +18° 48′ 00″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 71° S. North of latitude 71° 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 9,198 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 163 million years.