Pulsar
PSR J1840-0643
Radio pulsar · binary system
A neutron star spinning once every 0.036 seconds; the beams from its magnetic poles sweep across Earth on every turn. It shares a 945 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 | Scutum |
| Period | 35.578 ms (28 Hz) |
| Period derivative | 9.5×10⁻²⁰ s/s |
| Characteristic age | 5.9 billion years |
| Magnetic field | 1.9×10⁹ G |
| Spin-down luminosity | 8.4×10³¹ erg/s |
| Dispersion measure | 494.0 pc/cm³ |
| Distance | 4,989 pc (16.3 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.19 M☉ |
| Orbital period | 945 days |
| Eccentricity | 0.0021 |
| Discovery | 2013 · pksmb |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 18h 40m 09.0s |
| Declination (J2000) | −6° 43′ 36″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 83° N. 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 16 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 289 million years.