Pulsar
PSR J0557+1550
Millisecond pulsar · binary system
A millisecond pulsar spinning 391 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 4.847 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 | Orion |
| Period | 2.556 ms (391 Hz) |
| Period derivative | 7.4×10⁻²¹ s/s |
| Characteristic age | 5.5 billion years |
| Magnetic field | 1.4×10⁸ G |
| Spin-down luminosity | 1.7×10³⁴ erg/s |
| Dispersion measure | 102.6 pc/cm³ |
| Distance | 1,834 pc (6.0 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.23 M☉ |
| Orbital period | 4.847 days |
| Eccentricity | 0.000009 |
| Discovery | 2015 · palfa |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 5h 57m 31.4s |
| Declination (J2000) | +15° 50′ 06″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 74° S. North of latitude 74° N it never sets. It stands highest at midnight in December, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 5,982 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 106 million years.