Pulsar
PSR J0721-2038
Millisecond pulsar · binary system
A millisecond pulsar spinning 64 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 5.461 days orbit with a CO white dwarf. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Canis Major |
| Period | 15.542 ms (64 Hz) |
| Period derivative | 4.4×10⁻²⁰ s/s |
| Characteristic age | 5.6 billion years |
| Magnetic field | 8.4×10⁸ G |
| Spin-down luminosity | 4.6×10³² erg/s |
| Dispersion measure | 76.0 pc/cm³ |
| Distance | 2,680 pc (8.7 thousand ly) |
| Companion | CO white dwarf (estimated), ~0.55 M☉ |
| Orbital period | 5.461 days |
| Eccentricity | 0.000102 |
| Discovery | 2013 · pkspa, gbncc |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 7h 21m 42.9s |
| Declination (J2000) | −20° 38′ 07″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 69° N. South of latitude 69° S it never sets. It stands highest at midnight in January, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 8,741 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 155 million years.