Pulsar
PSR B2154+40 (J2157+4017)
Radio pulsar
A neutron star spinning once every 1.53 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 | Cygnus |
| Period | 1.525 s |
| Period derivative | 3.4×10⁻¹⁵ s/s |
| Characteristic age | 7.0 million years |
| Magnetic field | 2.3×10¹² G |
| Spin-down luminosity | 3.8×10³¹ erg/s |
| Dispersion measure | 71.1 pc/cm³ |
| Distance | 2,900 pc (9.5 thousand ly) |
| Discovery | 1973 · gb1, gb3, gb4, lotaas |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 21h 57m 01.8s |
| Declination (J2000) | +40° 17′ 46″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 50° S. North of latitude 50° N it never sets. It stands highest at midnight in August, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 9,459 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 168 million years.