Pulsar
SGR 1806−20 (Magnetar)
The most powerful magnet in the universe; its 2004 giant flare rattled Earth's ionosphere
A magnetar with a magnetic field exceeding 10¹⁵ gauss — a quadrillion times Earth's. On 27 December 2004 a crust fracture on its surface released, in 0.2 seconds, as much energy as the Sun emits in 250,000 years; from 50,000 light-years away it ionised Earth's upper atmosphere and saturated satellite detectors. Slowly rotating (7.56 s) but with immense fields, such stars are soft gamma repeaters (SGRs).
| Type | Pulsar |
|---|---|
| Constellation | Sagittarius |
| Period | 7,56 s |
| Magnetic field | ~2 × 10¹⁵ G |
| Characteristic age | ~1,500 years |
| Giant flare | 27 December 2004 · ~10⁴⁶ erg |
| Distance | ~8,700 pc (~28,000 light-years) |
| Discovery | 1979 (gamma-ray bursts) · period: 1998, Kouveliotou et al. |
| Right ascension (J2000) | 18h 08m 39.4s |
| Declination (J2000) | −20° 24′ 40″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 70° N. South of latitude 70° 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 28 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 503 million years.