The June Bootids meteor shower
Key facts
- Peak
- around 23–27 June
- Active
- about 22 June to 2 July
- Rate at peak (ZHR)
- usually near zero; outbursts of 50–100 or more (1998) and 20–50 (2004)
- Speed
- 18 km/s
- Radiant
- Northern Boötes (near the border with Draco and Hercules)
- Parent body
- Comet 7P/Pons–Winnecke
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 June Bootids are a shower that can be completely absent for decades and then give a sudden, strong display. They are one of the best examples of how planets reshape comet dust trails.
The parent comet. Comet 7P/Pons–Winnecke was first seen in 1819 by Jean-Louis Pons, a French observer who found dozens of comets, and recovered in 1858 by the German astronomer Friedrich Winnecke. It now orbits the Sun about every six and a quarter years. Jupiter has moved its orbit a great deal over the past two centuries, so the comet's closest point to the Sun has drifted outward.
History. The shower was first noticed in 1916, when the English meteor observer William Denning saw a burst of meteors on 28 June. Further displays followed in 1921 and 1927, after which the shower was dropped from most lists. Then, on 27 June 1998, without warning, observers saw rates of 50 to 100 meteors an hour or more, lasting more than half a day. In 2004, on 23 June, a smaller outburst of about 20 to 50 an hour was predicted in advance and duly arrived. Later calculations showed that both outbursts came from dust released by the comet during the nineteenth century, which Jupiter had nudged into Earth's path.
What to expect. In most years nothing. In outburst years, slow meteors: at about 18 kilometres per second they glide across the sky, and many are bright. The display can last for hours.
Viewing. The radiant in northern Boötes is high in the evening sky from the UK and stays up most of the night, so the shower is well suited to northern observers. The difficulty is midsummer twilight: from Scotland and northern England the sky barely darkens in late June, so faint meteors are lost. Southern England, continental Europe and the United States have darker nights. Southern hemisphere observers see the radiant low or not at all.
Viewing tips
- Watch for forecasts, as outbursts depend on the comet's old dust trails.
- Look in the evening: the radiant is high in the north-west after dark.
- Find the radiant above the Plough's handle, between Boötes and Draco.
- Expect slow, often bright meteors that are easy to photograph.
- Choose the darkest hour, around 1 am local summer time, for faint members.
Read about the parent: Comet Pons–Winnecke, and the other comets behind meteor showers.