Pulsar
PSR J1748-2021H
Millisecond pulsar · in the globular cluster NGC6440
A millisecond pulsar spinning 351 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 8.66 h orbit with a very-low-mass companion. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Sagittarius |
| Period | 2.848 ms (351 Hz) |
| Period derivative | 1.9×10⁻¹⁹ s/s |
| Characteristic age | 238 million years |
| Magnetic field | 7.4×10⁸ G |
| Spin-down luminosity | 3.2×10³⁵ erg/s |
| Dispersion measure | 222.6 pc/cm³ |
| Distance | 8,864 pc (28.9 thousand ly) |
| Location | in the globular cluster NGC6440 |
| Companion | very-low-mass companion (estimated), ~0.007 M☉ |
| Orbital period | 8.66 h |
| Discovery | 2022 · misc |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 17h 48m 53.2s |
| Declination (J2000) | −20° 21′ 35″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 70° N. South of latitude 70° 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 29 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 513 million years.