Pulsar
PSR J1756-2251
Millisecond pulsar · binary system
A millisecond pulsar spinning 35 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 7.67 h orbit with a neutron star. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Sagittarius |
| Period | 28.462 ms (35 Hz) |
| Period derivative | 1.0×10⁻¹⁸ s/s |
| Characteristic age | 443 million years |
| Magnetic field | 5.5×10⁹ G |
| Spin-down luminosity | 1.7×10³³ erg/s |
| Dispersion measure | 121.2 pc/cm³ |
| Distance | 730 pc (2.4 thousand ly) |
| Companion | neutron star (estimated), ~1.35 M☉ |
| Orbital period | 7.67 h |
| Eccentricity | 0.1806 |
| Discovery | 2004 · pksmb, htru_pks |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 17h 56m 46.6s |
| Declination (J2000) | −22° 51′ 59″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 67° N. South of latitude 67° 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 around 356 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 42 million years.