Pulsar
Geminga (PSR J0633+1746)
A radio-quiet gamma-ray pulsar; its name means "it's not there" in Milanese dialect
The mysterious gamma-ray source found by the SAS-2 satellite in 1972; for 20 years no radio or optical counterpart could be found ("Geminga": the gamma-ray source in Gemini — and in Milanese dialect "gh'è minga", "it's not there"). In 1992 ROSAT detected 237 ms X-ray pulses. One of the nearest pulsars to us.
| Type | Pulsar |
|---|---|
| Constellation | Gemini |
| Period | 237 ms |
| Characteristic age | 342,000 years |
| Magnetic field | 1,6 × 10¹² G |
| Distance | 250 pc (815 light-years) |
| Band | Gamma and X-rays (radio-quiet) |
| Discovery | 1972 (SAS-2) · pulsar: 1992, Halpern & Holt (ROSAT) |
| Right ascension (J2000) | 6h 33m 54.2s |
| Declination (J2000) | +17° 46′ 12″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 72° S. North of latitude 72° N 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 1211. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 14 million years.