The Gamma Crucids meteor shower
Key facts
- Peak
- around 14 February, in active years
- Active
- mid-February, in active years
- Rate at peak (ZHR)
- usually none; an outburst recorded by cameras in 2021
- Speed
- about 57 km/s
- Radiant
- Crux (near Gacrux, Gamma Crucis, at the top of the Southern Cross)
- Parent body
- An unidentified Halley-type comet
Dates shift slightly from year to year. This year's peak is in the events calendar.
The Gamma Crucids are a southern shower that appeared as an outburst in February 2021, radiating from the most famous constellation of the southern sky, the Southern Cross.
The 2021 outburst. Between 11 and 15 February 2021, video camera networks in Australia, Chile and New Zealand, part of an international project to measure meteor orbits, recorded a burst of meteors from near the Southern Cross, with the highest activity on 14 February. About forty meteors were filmed from more than one station, so their orbits could be calculated precisely. The shower was given its own name and number.
The parent. The orbits are steeply tilted, more than 90 degrees to Earth's, which means the meteoroids go round the Sun in the opposite direction to the planets, and they take several decades to complete an orbit. That pattern is typical of a Halley-type comet, a comet with an orbital period of about 20 to 200 years. No such comet is known on this orbit.
A link with the Alpha Centaurids? The radiant is not far from that of the Alpha Centaurids, a southern shower that gave a strong outburst on 8 February 1980. Researchers have suggested that the two may be related, perhaps different parts of the same stream, but this has not been confirmed.
What to expect. In most years, nothing noticeable. In an active year, fast meteors from near the Southern Cross. At about 57 kilometres per second they are quick, and some may leave trains.
Viewing. The Southern Cross is circumpolar from Australia, New Zealand, southern Africa and much of South America, so the radiant is visible for much of the night in February, highest before dawn. From the UK and most of the northern hemisphere it never rises.
Viewing tips
- Watch from the southern hemisphere in the hours before dawn.
- Find Gacrux, the reddish star at the top of the Southern Cross.
- Run a meteor camera through mid-February to catch any return.
- Separate them from Alpha Centaurids, whose radiant lies a little further east.
- Report any burst of fast meteors from Crux with exact times.