Pulsar
PSR J1638-4725
Radio pulsar · binary system
A neutron star spinning once every 0.764 seconds; the beams from its magnetic poles sweep across Earth on every turn. It shares a 1,941 days orbit with a neutron star. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Ara |
| Period | 763.9 ms |
| Period derivative | 4.8×10⁻¹⁵ s/s |
| Characteristic age | 2.5 million years |
| Magnetic field | 1.9×10¹² G |
| Spin-down luminosity | 4.2×10³² erg/s |
| Dispersion measure | 552.1 pc/cm³ |
| Distance | 4,742 pc (15.5 thousand ly) |
| Companion | neutron star (estimated), ~8.08 M☉ |
| Orbital period | 1,941 days |
| Eccentricity | 0.9550 |
| Discovery | 2006 · pksmb |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 16h 38m 12.9s |
| Declination (J2000) | −47° 25′ 32″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 43° N. South of latitude 43° S it never sets. It stands highest at midnight in May, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 15 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 274 million years.