 | |
| Discovery | |
|---|---|
| Discovered by | LINEAR 1.0-mreflector[1] |
| Discovery date | 3 February 2004 (asteroidal) 30 March 2004 (tail) |
| Designations | |
| 2004 CB | |
| Orbital characteristics | |
| Epoch | 2014-May-23 (JD 2456800.5)[2] |
| Aphelion | 4.952AU (Q) |
| Perihelion | 0.9695 AU (q) |
| Semi-major axis | 2.961 AU (a) |
| Eccentricity | 0.67258 |
| Orbital period | 5.09yr |
| Inclination | 21.243° |
| Last perihelion | 2019-Jun-12[2] 2014-May-06[3] 2009-Apr-15[3] |
| Next perihelion | 2024-Jul-14[4] |
| EarthMOID | 0.05 AU (7,500,000 km)[5] |
| Physical characteristics | |
| Dimensions | 3.9 × 2.7 × 2.6 km[6] |
| 10.9 hours[7] | |
| Comet total magnitude (M1) | 18.1[5] |
209P/LINEAR is aperiodiccomet with an orbital period of 5.1 years. The comet has extremely low activity for its size and is probably in the process of evolving into anextinct comet.[6]
The comet discovered on 3 February 2004 byLincoln Near-Earth Asteroid Research (LINEAR) using a 1.0-metre (39 in)reflector.[1] Initially it was observed without acoma and named2004 CB as aminor planet or asteroid, but in March 2004Robert H. McNaught observed acomet tail which confirmed it as a comet.[8] It was given the permanent number 209P on 12 December 2008 as it was the second observed appearance of the comet.[9]Prediscovery images of the comet, dating back to December 2003, were found during 2009.[8]
209P/LINEAR came toperihelion (closest approach to the Sun) on 6 May 2014.[3] On 29 May 2014 the comet passed 0.0554 AU (8,290,000 km; 5,150,000 mi) from Earth,[5] but only brightened to aboutapparent magnitude 12.[10] The 2014 Earth approach was the 9th closest known comet approach to Earth.[11] The close approach allowed thecomet nucleus to be imaged byArecibo, producing the most detailed radar image of a comet nucleus to that date.[12] The radar imaging showed thecomet nucleus is elongated and about 2.4 km by 3 km in size,[12] later refined to 3.9 × 2.7 × 2.6 km.[6] No evidence of large dust particles were detected in the coma.[7] The comet also had very low water production,(2.5±0.2)×1025 mol/s, from an active area measuring just 0.007 km2.[6]
209P/LINEAR was recovered on 31 December 2018 at magnitude 19.2 by Hidetaka Sato.[13]
Preliminary results by Esko Lyytinen andPeter Jenniskens, later confirmed by other researchers, predicted[14][15][16] 209P/LINEAR might a bigmeteor shower which would come from theconstellationCamelopardalis on the night of 23/24 May 2014. It was possible that there could be 100 to 400 meteors per hour.[14] All the trails from the comet from 1803 through 1924 were expected to intersect Earth's orbit during May 2014.[14] The peak activity was expected to occur around 24 May 2014 7hUT when dust trails produced from past returns of the comet could pass 0.0002 AU (30,000 km; 19,000 mi) from Earth.[16] The 2014 Camelopardalids only generated 10–15 visual meteors per hour.[17][18] But the expectedradiant and date of visual maximum were correctly predicted.[18] The shower peaked around 6h UT on 24 May 2014.[18] The Canadian Meteor Orbit Radar (CMOR) detected the shower using HF/VHF radar echos but the particles were too small for visual detection. Earth encountered the 1939 stream around 24 May 2019 8h UT with aZHR of ~5. TheEta Aquariids also occur at this time of year.[19]
The comet has also being suggested to be the parent body of the lambda Draconids, which is active from April 24 to June 4, and peaks around May 12. However it is possible that it is the same shower as the Camelopardalids.[20]
209P/LINEAR may also be the source of the weak 6–14 June meteor shower "sigma Ursae Majorids" (SIM #677).[11]
| Numbered comets | ||
|---|---|---|
| Previous 208P/McMillan | 209P/LINEAR | Next 210P/Christensen |
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