40 likes | 240 Views
Impact on Asteroid?. P/2010 A2 dusty tail Detected 6 Jan 2010 by LINEAR and classified as a comet. Located in main asteroid belt (a = 2.290 AU, e = 0.1244, I = 5.25º). 120 m diameter “nucleus” & tail of mm-size dust particles. Interpreted to be an asteroid that was hit by another
E N D
Impact on Asteroid? P/2010 A2 dusty tail Detected 6 Jan 2010 by LINEAR and classified as a comet. Located in main asteroid belt (a = 2.290 AU, e = 0.1244, I = 5.25º). 120 m diameter “nucleus” & tail of mm-size dust particles. Interpreted to be an asteroid that was hit by another asteroid a few meters in diameter Jewitt et al. (2010) Snodgrass et al. (2010)
Disintegrating Asteroid? P/2013 R3 Detected 15 Sept 2013 by Catalina Sky Survey and Pan STARRS; classified as a comet. Occurs in main asteroid belt. Composed of 10 objects. The four largest fragments are up to 360 m in diameter. Estimated mass of 200,000 tons. Interpreted to be a weak asteroid that was spun up by sunlight until its rotation caused it to disintegrate. The fragments are separating at a speed of only 1 mph. (Jewitt et al.) NASA Science News 6 March 2014
Comets - What is in a name? • Naming conventions for survey-detected comets (revised in 2003) • Prefix • P/ = periodic • C/ = non-periodic • X/ = comet without a reliable orbit • D/ = broken up or otherwise lost • A/ = object first thought to be a comet and later reclassified as an asteroid • Year of discovery • Followed by letter indicating half-month of discovery • A for first half of January • B for second half of January • C for first half of February, etc. • & number indicating order of discovery • Thus, P/2010 A2 was classified as a periodic comet when it was discovered in the first half of January of 2010; it was the second comet of that period.
Asteroids - What is in a name? • Naming conventions for asteroids • Provisional designation assigned when first observed • Composed of the year • A letter to indicate the half-month of discovery • A letter and subscript number to indicate sequential order of discovery within that year; the subscript indicates how many times the alphabet has been cycled before the object was discovered. (I is not used, so each cycle has 25 letters rather than 26 letters) • e.g., 1993 HH3 was discovered in 1993, in the first half of April; it was the (3 x 25) + 8 = 63rd minor planet in that period. • Once enough data is calculated to define an orbit • A sequential number or designation is assigned • e.g., (8391) • After a designation is assigned, the discoverer can propose a name • e.g., The Spacewatch program proposed the name Kring, which was accepted by the IAU • Final name: (8391) Kring = 1993 HH3