The December Chi Virginids meteor shower
Key facts
- Peak
- around 9 December
- Active
- late November to mid-December
- Rate at peak (ZHR)
- very low (detected mainly by video)
- Speed
- about 69 km/s
- Radiant
- Virgo (near the star Chi Virginis, west of Spica)
- Parent body
- Unknown; probably a long-period comet
Dates shift slightly from year to year. This year's peak is in the events calendar.
The December Chi Virginids are a very fast pre-dawn shower from Virgo, active in the week before the Geminid peak. They were found in video data from Japan.
Discovery. The shower was one of eleven new streams announced in 2009 by Takashi Kanamori of Tokyo, who analysed two years of recordings from video cameras at several Japanese sites. Matching orbits revealed a group of very fast meteors from near Chi Virginis.
The radiant. Chi Virginis is a modest star in the western part of Virgo, north-west of Spica and just south of the celestial equator. In December, Virgo rises in the east in the early hours of the morning and is reasonably high by dawn.
The meteors. At about 69 kilometres per second, the December Chi Virginids are among the fastest shower meteors, close to the Leonids. Such speeds come from meteoroids moving almost head on against Earth, on retrograde orbits, typical of long-period comets. No parent has been identified.
What to expect. Very few meteors, mostly quick, faint streaks in the morning sky. The Geminids, peaking a few days later, are much more numerous and move at only half the speed, so a very fast meteor from the east before dawn in early December has a fair chance of being a Chi Virginid or a sporadic meteor rather than a Geminid.
Viewing. The radiant is near the celestial equator, so the shower can be seen from both hemispheres. From the UK the best time is the two or three hours before dawn, when Virgo is highest.
Radiants that rise only in the early morning, like this one, are a reminder of a general rule: the hours before dawn usually produce more meteors than the evening, because that side of Earth faces forward along its orbit.
Viewing tips
- Watch in the two or three hours before dawn, when Virgo is rising.
- Find Spica and look north-west of it.
- Expect very fast, short meteors.
- Tell them from slow Geminids by speed and direction.
- Run a camera to record faint members.