Pulsar
PSR B1821-24A (J1824-2452A)
Millisecond pulsar · in the globular cluster M28(NGC6626)
A millisecond pulsar spinning 327 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 | 3.054 ms (327 Hz) |
| Period derivative | 1.6×10⁻¹⁸ s/s |
| Characteristic age | 30 million years |
| Magnetic field | 2.3×10⁹ G |
| Spin-down luminosity | 2.2×10³⁶ erg/s |
| Dispersion measure | 119.9 pc/cm³ |
| Distance | 5,370 pc (17.5 thousand ly) |
| Location | in the globular cluster M28(NGC6626) |
| Discovery | 1987 · misc, FermiAssoc, pksmb |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 18h 24m 32.0s |
| Declination (J2000) | −24° 52′ 11″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 65° N. South of latitude 65° 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 18 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 311 million years.