Title: Finding Long Lost Lexell's Comet: The Fate of the First Discovered Near-Earth Object Authors: Quan-Zhi Ye, Paul A. Wiegert, Man-To Hui
Jupiter-family Comet D/1770 L1 (Lexell) was the first discovered Near-Earth Object (NEO), and passed the Earth on 1770 Jul 1 at a recorded distance of 0.015 au. The comet was subsequently lost due to unfavorable observing circumstances during its next apparition followed by a close encounter with Jupiter in 1779. Since then, the fate of D/Lexell has attracted interest from the scientific community, and now we revisit this long-standing question. We investigate the dynamical evolution of D/Lexell based on a set of orbits recalculated using the observations made by Charles Messier, the comet's discoverer, and find that there is a 98% chance that D/Lexell remains in the Solar System by the year of 2000. This finding remains valid even if a moderate non-gravitational effect is imposed. Messier's observations also suggest that the comet is one of the largest known near-Earth comets, with a nucleus of \gtrsim 10 km in diameter. This implies that the comet should have been detected by contemporary NEO surveys regardless of its activity level if it has remained in the inner Solar System. We identify asteroid 2010 JL33 as a possible descendant of D/Lexell, with a 0.8% probability of chance alignment, but a direct orbital linkage of the two bodies has not been successfully accomplished. We also use the recalculated orbit to investigate the meteors potentially originating from D/Lexell. While no associated meteors have been unambiguously detected, we show that meteor observations can be used to better constrain the orbit of D/Lexell despite the comet being long lost.
Radar imaging at NASA's Goldstone Solar System Radar in the California desert on Dec. 11 and 12, 2010, revealed defining characteristics of recently discovered asteroid 2010 JL33. The images have been made into a short movie that shows the celestial object's rotation and shape. A team led by Marina Brozovic, a scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., made the discovery. Data from the radar reveal 2010 JL33 to be an irregular, elongated object roughly 1.8 kilometres wide that rotates once every nine hours. The asteroid's most conspicuous feature is a large concavity that may be an impact crater. Read more
The 780 - 1800 metre wide asteroid 2010 JL33 will make a close pass (16.6 lunar distances, 0.0427 AU), travelling at 20.79 km/second, to the Earth-Moon system on the 9th December, 2010 @ 03:34 UT. See more
The Lunar Distance (LD), the distance between Earth and the Moon, equals 384,401 km, (or 0.00256 AU).
Minimum Distance: 0.04269 AU Approach Date: 02:24 UT, 9th December, 2010 Maximum magnitude: 13.4 V Date at maximum brightness: 21:00 UT, 10th December, 2010 Maximum angular speed: 40.6"/min
Orbital elements: 2010 JL33 PHA, Earth MOID = 0.0337 AU Epoch 2010 July 23.0 TT = JDT 2455400.5 MPC M 337.76507 (2000.0) P Q n 0.22756491 Peri. 308.49285 +0.99659820 -0.03435637 a 2.6570467 Node 53.60068 +0.06434139 +0.89235661 e 0.7423794 Incl. 5.34017 -0.05149970 +0.45002147 P 4.33 H 17.7 G 0.15 U 1
Minimum Distance: 0.06981 AU Approach Date: 14:23 UT, 9th December, 2010 Maximum magnitude: 14.5 V Date at maximum brightness: 04:00 UT, 11th December, 2010 Maximum angular speed: 25.64 "/min
Minimum Distance: 0.04623 AU Approach Date: 02:24 UT, 8th December, 2010 Maximum magnitude: 13.6 V Date at maximum brightness: 02:00 UT, 10th December, 2010 Maximum angular speed: 36.14 "/min