Pulsar
PSR B1820-30A (J1823-3021A)
Millisecond pulsar · in the globular cluster NGC6624
A millisecond pulsar spinning 184 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Sagittarius |
| Period | 5.440 ms (184 Hz) |
| Period derivative | 3.4×10⁻¹⁸ s/s |
| Characteristic age | 26 million years |
| Magnetic field | 4.3×10⁹ G |
| Spin-down luminosity | 8.3×10³⁵ erg/s |
| Dispersion measure | 86.9 pc/cm³ |
| Distance | 8,020 pc (26.2 thousand ly) |
| Location | in the globular cluster NGC6624 |
| Discovery | 1994 · misc, FermiBlind, htru_pks, pks70 |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 18h 23m 40.5s |
| Declination (J2000) | −30° 21′ 40″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 60° N. South of latitude 60° 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 26 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 464 million years.