Pulsar
PSR B1937+21 (J1939+2134)
Millisecond pulsar
A millisecond pulsar spinning 642 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Vulpecula |
| Period | 1.558 ms (642 Hz) |
| Period derivative | 1.1×10⁻¹⁹ s/s |
| Characteristic age | 235 million years |
| Magnetic field | 4.1×10⁸ G |
| Spin-down luminosity | 1.1×10³⁶ erg/s |
| Dispersion measure | 71.0 pc/cm³ |
| Distance | 3,500 pc (11.4 thousand ly) |
| Discovery | 1982 · ar2, ar3, ar4, gbncc, palfa, fast_gpps |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 19h 39m 38.6s |
| Declination (J2000) | +21° 34′ 59″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 68° S. North of latitude 68° 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 11 thousand 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 203 million years.