The Theta Pyxidids meteor shower
Key facts
- Peak
- around 2 December
- Active
- late November to early December
- Rate at peak (ZHR)
- very low (detected mainly by video)
- Speed
- about 61 km/s
- Radiant
- Pyxis (the Compass, south of Hydra's head)
- Parent body
- Unknown
Dates shift slightly from year to year. This year's peak is in the events calendar, and the meteor-shower planner shows how high the radiant climbs from where you live, night by night.
The Theta Pyxidids are a fast, faint shower from Pyxis, the Mariner's Compass, a small southern constellation. They were identified from video data and are active in the busy early-December period before the Geminids.
Discovery. The shower was one of eleven announced in 2009 by Takashi Kanamori in Tokyo, from two years of video recordings made at several Japanese sites. Comparing orbits revealed a group of fast meteors from near Theta Pyxidis.
The constellation. Pyxis was introduced in the 1750s by the French astronomer Nicolas-Louis de Lacaille, who mapped the southern sky from the Cape of Good Hope. He named many new constellations after scientific instruments. Pyxis lies beside the stern of the old ship constellation Argo, and represents a ship's magnetic compass.
The meteors. At about 61 kilometres per second, the meteors are fast. No parent body has been identified, though the speed suggests a comet on a steeply tilted or retrograde orbit.
What to expect. Very few meteors. Early December brings the Puppid-Velids, the Sigma Hydrids and the first Geminids into the same region of sky, so members of this shower are hard to recognise by eye. Video networks in both hemispheres now record it.
Viewing. The radiant is about 25 degrees south of the celestial equator. From southern England it rises only about 13 degrees above the southern horizon at best, in the hours before dawn. From the tropics and the southern hemisphere it is much better placed, high in the sky before dawn.
Viewing tips
- Watch in the hours before dawn, when Pyxis is highest.
- Find the head of Hydra, then look south for Pyxis.
- Observe from the southern hemisphere for a high radiant.
- Separate fast Pyxidids from slower Geminids by speed and direction.
- Use a camera to catch faint members.