Pulsar
PSR J1555-2908
Millisecond pulsar · binary system
A millisecond pulsar spinning 559 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 5.60 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 | Scorpius |
| Period | 1.788 ms (559 Hz) |
| Period derivative | 4.5×10⁻²⁰ s/s |
| Characteristic age | 636 million years |
| Magnetic field | 2.9×10⁸ G |
| Spin-down luminosity | 3.1×10³⁵ erg/s |
| Dispersion measure | 75.9 pc/cm³ |
| Distance | 7,559 pc (24.7 thousand ly) |
| Companion | very-low-mass companion (estimated), ~0.059 M☉ |
| Orbital period | 5.60 h |
| Eccentricity | 0.000005 |
| Discovery | 2022 · FermiAssoc |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 15h 55m 40.7s |
| Declination (J2000) | −29° 08′ 28″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 61° N. South of latitude 61° S it never sets. It stands highest at midnight in May, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 25 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 437 million years.