Pulsar
PSR J1921+0137
Millisecond pulsar · binary system
A millisecond pulsar spinning 401 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 9.929 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 | Aquila |
| Period | 2.496 ms (401 Hz) |
| Period derivative | 1.9×10⁻²⁰ s/s |
| Characteristic age | 2.0 billion years |
| Magnetic field | 2.2×10⁸ G |
| Spin-down luminosity | 4.9×10³⁴ erg/s |
| Dispersion measure | 104.9 pc/cm³ |
| Distance | 5,084 pc (16.6 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.27 M☉ |
| Orbital period | 9.929 days |
| Eccentricity | 0.000037 |
| Discovery | 2016 · FermiAssoc, fast_gpps |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 19h 21m 30.3s |
| Declination (J2000) | +1° 37′ 26″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 88° S. 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 17 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 294 million years.