Pulsar
PSR J1908+2105
Millisecond pulsar · binary system
A millisecond pulsar spinning 390 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 3.51 h orbit with a very-low-mass companion. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Sagitta |
| Period | 2.564 ms (390 Hz) |
| Period derivative | 1.4×10⁻²⁰ s/s |
| Characteristic age | 2.9 billion years |
| Magnetic field | 1.9×10⁸ G |
| Spin-down luminosity | 3.2×10³⁴ erg/s |
| Dispersion measure | 61.9 pc/cm³ |
| Distance | 2,601 pc (8.5 thousand ly) |
| Companion | very-low-mass companion (estimated), ~0.063 M☉ |
| Orbital period | 3.51 h |
| Discovery | 2016 · FermiAssoc |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 19h 08m 57.3s |
| Declination (J2000) | +21° 05′ 03″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 69° S. North of latitude 69° 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 8,483 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 150 million years.