Pulsar
PSR J2215+5135
Millisecond pulsar · binary system
A millisecond pulsar spinning 383 times per second: an old neutron star spun up again (“recycled”) by matter transferred from a companion. It shares a 4.14 h 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 | Lacerta |
| Period | 2.610 ms (383 Hz) |
| Period derivative | 3.3×10⁻²⁰ s/s |
| Characteristic age | 1.2 billion years |
| Magnetic field | 3.0×10⁸ G |
| Spin-down luminosity | 7.4×10³⁴ erg/s |
| Dispersion measure | 69.2 pc/cm³ |
| Distance | 2,773 pc (9.0 thousand ly) |
| Companion | helium white dwarf (estimated), ~0.24 M☉ |
| Orbital period | 4.14 h |
| Eccentricity | 0.000011 |
| Discovery | 2011 · FermiAssoc, gbt350, fast_gpps |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 22h 15m 32.7s |
| Declination (J2000) | +51° 35′ 36″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 38° S. North of latitude 38° N it never sets. It stands highest at midnight in August, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 9,044 years ago. At that time the first farming villages were being founded; there was no writing yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 160 million years.