Pulsar
PSR J1731-1847
Millisecond pulsar · binary system
A millisecond pulsar spinning 427 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 7.47 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 | Ophiuchus |
| Period | 2.345 ms (427 Hz) |
| Period derivative | 2.5×10⁻²⁰ s/s |
| Characteristic age | 1.5 billion years |
| Magnetic field | 2.5×10⁸ G |
| Spin-down luminosity | 7.8×10³⁴ erg/s |
| Dispersion measure | 106.5 pc/cm³ |
| Distance | 4,782 pc (15.6 thousand ly) |
| Companion | very-low-mass companion (estimated), ~0.039 M☉ |
| Orbital period | 7.47 h |
| Eccentricity | 0.000029 |
| Discovery | 2010 · htru_pks |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 17h 31m 17.6s |
| Declination (J2000) | −18° 47′ 33″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 71° N. South of latitude 71° 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 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 277 million years.