Pulsar
PSR J1938+2012
Millisecond pulsar · binary system
A millisecond pulsar spinning 380 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 16.256 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 | Vulpecula |
| Period | 2.634 ms (380 Hz) |
| Period derivative | 7.5×10⁻²² s/s |
| Characteristic age | 55.6 billion years |
| Magnetic field | 4.5×10⁷ G |
| Spin-down luminosity | 1.6×10³³ erg/s |
| Dispersion measure | 236.9 pc/cm³ |
| Distance | 6,301 pc (20.6 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.21 M☉ |
| Orbital period | 16.256 days |
| Eccentricity | 0.000010 |
| Discovery | 2015 · palfa |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 19h 38m 40.1s |
| Declination (J2000) | +20° 12′ 51″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 70° S. North of latitude 70° 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 21 thousand years ago. At that time Homo sapiens was spreading out of Africa; there was no farming yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 365 million years.