Transcript Fragmenting Asteroids, Comets, and Their Names (PPT)

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).
Interpreted to be an asteroid that was hit by another
asteroid a few meters in diameter
LPI-JSC Center for Lunar Science & Exploration
2014
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120 m diameter
“nucleus” & tail of
mm-size dust
particles.
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.
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.)
LPI-JSC Center for Lunar Science & Exploration
2014
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The four largest
fragments are up to
360 m in diameter.
Estimated mass of
200,000 tons.
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.
LPI-JSC Center for Lunar Science & Exploration
2014
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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
LPI-JSC Center for Lunar Science & Exploration
2014
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