Comet Kiess
A long-period comet whose single narrow dust trail gives the Aurigids rare, predictable outbursts.
Key facts
- Designation
- C/1911 N1 (Kiess)
- Type
- Long-period comet
- Orbital period
- about 2,000 to 2,500 years
- Closest to the Sun
- about 0.68 AU (about 102 million km)
- Farthest from the Sun
- a few hundred AU
- Tilt of orbit
- about 148° (retrograde)
- Nucleus
- not measured
- Discovered
- by Carl Kiess at Lick Observatory, California, on 6 July 1911
- Returns
- passed perihelion on 30 June 1911; not expected back for about two thousand years
Orbit
Comet Kiess takes two thousand years or more to orbit the Sun. Its path takes it into the inner Solar System only briefly, and it moves backwards relative to the planets, so its meteors hit Earth fast, at about 67 km/s.
Size and nature
The comet was seen only in 1911, when it reached naked-eye brightness for a short time. Its nucleus has never been measured. Because its period is so long, there has been only one earlier pass in recorded history to lay down dust near Earth.
History
Carl Kiess found it on a photographic plate at Lick Observatory in July 1911, just after it had passed the Sun. In 1935 observers saw a sudden burst of meteors from Auriga, the Charioteer, at the start of September. Similar outbursts in 1986 and 1994 led the Finnish astronomer Esko Lyytinen and Peter Jenniskens to work out that they came from a single dust trail released at the comet's previous pass, about two thousand years ago.
Meteor showers
The Aurigids usually show only a handful of meteors around 1 September. Using the trail model, Jenniskens and Lyytinen predicted an outburst for 1 September 2007, timed to within minutes. It came on schedule, with around 100 to 200 meteors an hour seen from western North America, and aircraft carried scientists up to watch above the clouds.
Its meteor showers
- The Aurigids peak around 31 August to 1 September; about 6; brief outbursts in 1935, 1986, 1994 and 2007 an hour at best; 66 km/s
Key dates
| Date | What happened |
|---|---|
| 6 July 1911 | Carl Kiess discovered the long-period comet behind the Aurigid meteors. |
| 1 September 2007 | A predicted Aurigid outburst from the dust trail of Comet Kiess arrived on time. |
Did you know?
The dust in the 2007 outburst had been travelling for about two thousand years since it left the comet.
Aurigid outbursts last only an hour or two.
Scientists flew in aircraft in 2007 to make sure clouds did not hide the display.