The Psi Ursae Majorids meteor shower
Key facts
- Peak
- around 5 December
- Active
- late November to mid-December
- Rate at peak (ZHR)
- very low (detected mainly by video)
- Speed
- about 62 km/s
- Radiant
- Ursa Major (near the star Psi Ursae Majoris, below the bowl of the Plough)
- 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 Psi Ursae Majorids are a fast, faint December shower from below the bowl of the Plough. They were identified in Japanese video data and confirmed by later camera networks.
Discovery. The shower was one of eleven announced in 2009 by Takashi Kanamori of Tokyo, using two years of multi-station video data. Meteors seen from more than one camera were given orbits, and a group from near Psi Ursae Majoris in early December stood out.
The radiant. Psi Ursae Majoris is a fairly bright star below the bowl of the Plough, roughly in line with the two Pointers, but on the opposite side of the bowl from the Pole Star. From the UK the radiant is circumpolar, rising high in the north-east after midnight in December.
The meteors. At about 62 kilometres per second they are fast, which means the meteoroids meet Earth almost head on. Debris from long-period comets on steeply tilted orbits behaves like this. No parent body has been identified.
What to expect. Very few meteors. The shower is active in the run-up to the Geminids, whose radiant is far to the south-west in Gemini. Fast meteors from the Plough area in early December may be Psi Ursae Majorids; most visual observers record them simply as sporadic meteors.
Why it matters. Showers like this are part of the hidden structure of the meteor sky. Each night, video networks around the world sort thousands of meteors into showers by comparing orbits, steadily confirming or rejecting candidates such as this one. That work is only possible because many observers, professional and amateur, keep cameras running night after night.
Viewing. This is a northern shower. From the southern hemisphere it is low or below the horizon.
Viewing tips
- Find the bowl of the Plough and look below it for Psi Ursae Majoris.
- Watch after midnight, when Ursa Major is high in the north-east.
- Expect fast, mostly faint meteors.
- Separate them from Geminids, which come from the south-west.
- Run a camera to record possible members.