Pulsar
PSR J1804-2717
Millisecond pulsar · binary system
A millisecond pulsar spinning 107 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 11.129 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 | Sagittarius |
| Period | 9.343 ms (107 Hz) |
| Period derivative | 4.1×10⁻²⁰ s/s |
| Characteristic age | 3.6 billion years |
| Magnetic field | 6.3×10⁸ G |
| Spin-down luminosity | 2.0×10³³ erg/s |
| Dispersion measure | 24.7 pc/cm³ |
| Distance | 909 pc (3.0 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.24 M☉ |
| Orbital period | 11.129 days |
| Eccentricity | 0.000034 |
| Discovery | 1996 · pks70, gbncc, pksmb |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 18h 04m 21.1s |
| Declination (J2000) | −27° 17′ 31″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 63° N. South of latitude 63° 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 940 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 53 million years.