Pulsar
PSR J1802-2124
Millisecond pulsar · binary system
A millisecond pulsar spinning 79 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 16.77 h 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 | Sagittarius |
| Period | 12.648 ms (79 Hz) |
| Period derivative | 7.3×10⁻²⁰ s/s |
| Characteristic age | 2.8 billion years |
| Magnetic field | 9.7×10⁸ G |
| Spin-down luminosity | 1.4×10³³ erg/s |
| Dispersion measure | 149.6 pc/cm³ |
| Distance | 800 pc (2.6 thousand ly) |
| Companion | CO white dwarf (estimated), ~0.98 M☉ |
| Orbital period | 16.77 h |
| Eccentricity | 0.000002 |
| Discovery | 2004 · pksmb, htru_pks |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 18h 02m 05.3s |
| Declination (J2000) | −21° 24′ 04″ |
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 June, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around 584 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 46 million years.