Pulsar
PSR J2042+0246
Millisecond pulsar · binary system
A millisecond pulsar spinning 221 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 77.201 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 | Delphinus |
| Period | 4.534 ms (221 Hz) |
| Period derivative | 1.4×10⁻²⁰ s/s |
| Characteristic age | 5.1 billion years |
| Magnetic field | 2.6×10⁸ G |
| Spin-down luminosity | 5.9×10³³ erg/s |
| Dispersion measure | 9.3 pc/cm³ |
| Distance | 636 pc (2.1 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.22 M☉ |
| Orbital period | 77.201 days |
| Eccentricity | 0.000166 |
| Discovery | 2016 · FermiAssoc, fast_gpps |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 20h 42m 11.0s |
| Declination (J2000) | +2° 46′ 15″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 87° 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 around 49 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 37 million years.