Pulsar
PSR B2315+21 (J2317+2149)
Radio pulsar
A neutron star spinning once every 1.44 seconds; the beams from its magnetic poles sweep across Earth on every turn. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Pegasus |
| Period | 1.445 s |
| Period derivative | 1.0×10⁻¹⁵ s/s |
| Characteristic age | 22 million years |
| Magnetic field | 1.2×10¹² G |
| Spin-down luminosity | 1.4×10³¹ erg/s |
| Dispersion measure | 20.9 pc/cm³ |
| Distance | 1,700 pc (5.5 thousand ly) |
| Discovery | 1978 · gb1, ar327, ar4, gb4, lotaas |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 23h 17m 57.8s |
| Declination (J2000) | +21° 49′ 48″ |
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 September, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 5,545 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 98 million years.