Comet 209P/LINEAR
A faint, worn-out comet whose much-hyped meteor shower in 2014 taught astronomers how little dust some comets make.
Key facts
- Designation
- 209P/LINEAR
- Type
- Jupiter-family comet
- Orbital period
- about 5.1 years
- Closest to the Sun
- 0.97 AU (about 145 million km)
- Farthest from the Sun
- about 5 AU, at Jupiter's distance
- Tilt of orbit
- about 19°
- Nucleus
- about 3.9 × 2.7 km
- Discovered
- on 3 February 2004 by the LINEAR survey in New Mexico, at first as an asteroid
- Returns
- at perihelion in 2024; next 2029
Orbit
The comet goes round the Sun every five years, between Earth's orbit and Jupiter's. On 29 May 2014 it passed about 8.3 million km from Earth, one of the closest comet approaches in recent decades. Its dust meets Earth slowly, at about 16 km/s.
Size and nature
Radar bounced off the comet during the 2014 pass showed a nucleus about 4 km long. Yet it is barely active, releasing only a tiny fraction of the gas and dust of a fresh comet of its size. It is probably far along the way to becoming an extinct comet, coated with a crust of dust that stops the ice from escaping.
History
The LINEAR survey, built to find near-Earth asteroids, picked it up in February 2004 as a point of light. The following month Robert McNaught saw a faint tail, revealing it as a comet.
Meteor showers
Calculations showed that Earth would pass through dust trails shed by the comet in the 1800s and early 1900s on 24 May 2014. Some forecasts suggested a storm of hundreds of meteors an hour, from a radiant in the dim northern constellation Camelopardalis. On the night, observers in North America saw only about 10 to 15 an hour, although the timing and radiant were exactly as predicted. The lesson was that the comet had been feeble for a long time. The Camelopardalids return each May, usually very weakly.
Its meteor showers
- The Camelopardalids peak around 24 May, only in some years; about usually none; about 15 at the 2014 display an hour at best; about 16–20 km/s
Key dates
| Date | What happened |
|---|---|
| 3 February 2004 | The LINEAR survey discovered the object later named Comet 209P/LINEAR. |
| 24 May 2014 | Earth passed through dust from Comet 209P/LINEAR, giving the first Camelopardalid display. |
| 29 May 2014 | Comet 209P/LINEAR passed about 8.3 million km from Earth. |
Did you know?
The 2014 shower was predicted almost to the minute, even though its strength was not.
Many comets found by asteroid surveys turn out to be low-activity, ageing comets like this one.
The Camelopardalids are named after the giraffe constellation.