Pulsar
PSR J0646-5455
Millisecond pulsar · binary system
A millisecond pulsar spinning 399 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 9.619 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 | Carina |
| Period | 2.507 ms (399 Hz) |
| Period derivative | 1.8×10⁻²¹ s/s |
| Characteristic age | 21.9 billion years |
| Magnetic field | 6.8×10⁷ G |
| Spin-down luminosity | 4.5×10³³ erg/s |
| Dispersion measure | 40.2 pc/cm³ |
| Distance | 367 pc (1.2 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.23 M☉ |
| Orbital period | 9.619 days |
| Eccentricity | 0.000035 |
| Discovery | 2025 · FermiAssoc |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 6h 46m 14.6s |
| Declination (J2000) | −54° 55′ 14″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 35° N. South of latitude 35° S it never sets. It stands highest at midnight in December, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 829. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 21 million years.