Doublet craters

Doublet Craters
(under construction)
compiled by Wm. Robert Johnston
last updated 10 July 2012

Doublet craters--slightly separated pairs of craters formed near-simultaneously--in many cases likely represent the result of impacts by binary asteroids. Survey-based estimates for craters over 10-20 km in diameter indicate that doublet craters comprise about 2% of craters on Mars, 10-15% on the Earth, and 2-14% on Venus. Binary asteroids are an obvious suspect as a source for doublet craters, given the signficant fraction of near-Earth objects estimated to be binary. They are not the only suspect, however. Some such craters represent breakup of "rubble-pile" asteroid just prior to impact, either from tidal forces or from impact with the atmosphere (in the cases of Venus and the Earth). The grazing impact of a single object which "skips" on impact is the preferred explanation in a few cases, such as craters Messier A and B on the Moon.

For particular bodies:

Cook, Melosh and Bottke suggested a doublet fraction of 2.2% for Venus based on an initial crater review and a 14% when including radar-dark "splotches" believed formed by impacting objects too small to reach the surface intact.
Three or four examples of doublet craters exist on Earth; these have been found to have similar geologic ages.
For Mars, Melosh, Ingram, and Bottke identified 3 likely doublets in a sample of 133 craters, giving a fraction of 2.3%. More extensive surveys will be possible based on recent Mars orbiter imagery.

The following table lists 56 identified doublet craters: 43 pairs on Venus, 4 on the Earth, 1 on the Moon, 6 on Mars, 1 on asteroid (4) Vesta, and 1 on Saturn's moon Tethys. Notes column includes crater names, where applicable. Sources are listed below.

body	crater #1		crater #2		crater diameters (km)		separation (km)	impactor sizes (km)		year reported	source	notes
body	lat (deg)	lon (deg)	lat (deg)	lon (deg)	#1	#2	separation (km)	#1	#2	year reported	source	notes
Venus	46.75	123.20	46.55	123.00	14.0	7.3	25.6			2003	C03a
Venus	-19.50	40.55	-19.55	40.40	30.0	14.0	15.8			2003	C03a
Venus	-39.05	260.25	-39.15	260.70	4.0	44.0	38.4			2003	C03a
Venus	4.95	169.75	4.95	170.90	14.0	10.0	121.0			2003	C03a
Venus	41.40	66.00	41.10	66.95	2.0	12.5	81.8			2003	C03a
Venus	18.40	101.85	17.90	102.60	12.5	19.0	91.9			2003	C03a
Venus	1.70	283.85	1.15	284.30	10.0	22.5	75.0			2003	C03a
Venus	0.55	143.15	0.00	142.60	20.0	6.0	82.1			2003	C03a
Venus	-22.00	342.70	-22.50	343.40	16.6	5.9	86.4			2003	C03a
Venus	-27.15	114.85	-27.25	114.20	10.0	4.5	62.0			2003	C03a
Venus	-32.70	163.15	-33.00	162.95	18.5	10.0	36.3			2003	C03a
Venus	-73.90	195.30	-74.70	195.00	4.0	8.0	84.9			2003	C03a
Venus	81.00	222.50	80.95	228.60	28.5	4.5	101.2			2003	C03a
Venus	80.95	228.60	80.00	229.00	4.5	7.5	100.6			2003	C03a
Venus	72.20	99.60	71.10	100.00	4.0	10.0	116.9			2003	C03a
Venus	41.10	66.95	40.60	65.30	12.5	2.0	142.0			2003	C03a
Venus	35.21	287.30	34.55	288.60	5.0	16.0	132.4			2003	C03a
Venus	28.20	106.80	27.80	108.10	15.5	8.0	128.4			2003	C03a
Venus	26.70	336.50	25.60	336.00	38.0	13.5	125.5			2003	C03a
Venus	23.75	94.55	22.60	94.10	21.5	2.8	129.1			2003	C03a
Venus	17.55	314.45	16.70	313.40	4.5	6.5	138.9			2003	C03a
Venus	-5.10	31.35	-6.40	30.80	16.0	13.0	149.0			2003	C03a
Venus	-12.40	307.40	-12.42	308.85	10.5	15.0	149.6			2003	C03a
Venus	-13.00	272.55	-13.40	271.20	25.0	20.0	145.1			2003	C03a
Venus	-26.10	168.95	-26.50	167.80	10.0	3.0	116.8			2003	C03a
Venus	-30.30	248.30	-30.30	249.40	21.0	10.0	100.3			2003	C03a
Venus	-57.85	250.50	-58.70	252.00	18.0	22.0	122.5			2003	C03a
Venus	-63.50	56.50	-63.75	59.50	14.0	27.0	143.2			2003	C03a
Venus	-64.20	232.20	-65.10	234.10	12.0	10.0	128.1			2003	C03a
Venus	-65.10	234.10	-66.50	234.20	10.0	8.0	147.9			2003	C03a
Venus	-67.00	241.80	-68.25	243.50	9.5	11.5	148.6			2003	C03a
Venus	40.00	51.90			40.0		22.1			2003	C03a
Venus	-3.45	265.00			18.0		15.9			2003	C03a
Venus	76.80	192.65			16.0		8.8			2003	C03a
Venus	59.15	215.40			10.2		10.1			2003	C03a
Venus	45.70	253.25			13.0		94.4			2003	C03a
Venus	37.70	305.50			20.0		18.5			2003	C03a
Venus	30.85	172.90			12.5		6.2			2003	C03a
Venus	23.60	350.10			14.0		12.4			2003	C03a
Venus	-6.75	334.10			12.0		6.2			2003	C03a
Venus	-12.42	308.85			15.0		7.1			2003	C03a
Venus	-15.30	84.90			10.5		5.3			2003	C03a
Venus	-32.70	163.15			18.5		32.0			2003	C03a
Earth	56.22	-74.50	56.08	-74.12	36.0	26.0	28.0	3.3	2.1	1991	M91a, M12a, E12a	West Clearwater Lake/East Clearwater Lake
Earth	48.88	10.62	48.68	10.07	24.0	3.8	46.0	2.3	0.2	1991	M91a, M12a, E12a	Ries/Steinheim
Earth	48.35	40.50	48.43	40.53	25.0	3.0	9.5	2.4	0.16	1991	M91a, M12a, E12a	Kamensk/Gusev
Earth	-34.62	139.07	-34.72	139.03	10.0	8.5	11.7			2012	M12a	Flaxman/Crawford
Moon	-2.00	48.00			13.0	13.0				1989	T89a	Messier A/Messier B
Mars	71.20	10.30	71.10	10.30	10.0	8.0	5.0			1996	M96a
Mars	70.50	18.70	70.40	18.60	5.2	10.0	8.0			1996	M96a
Mars	69.90	120.80	69.80	120.90	10.0	6.0	5.0			1996	M96a
Mars	32.00	107.00								2007	M07a
Mars	26.20	134.10								2011	M10a
Mars	-16.70	265.40								2011	M11a
Vesta	-75.00	108.00								2012	D12a
Tethys										2007	C07a

Sources:

B96a: Bottke, W. F. Jr., and H. J. Melosh, 1996, Binary asteroids and the formation of doublet craters, Icarus, 124:372-391. [http://www.sciencedirect.com/science/article/pii/S0019103596902158].
B96b: Bottke, W. F. Jr., and H. J. Melosh, 1996, Formation of asteroid satellites and doublet craters by planetary tidal forces, Nature, 381:51-53. [http://www.boulder.swri.edu/~bottke/Reprints/Bottke_Nature_1996_381_51_Binary_Doublet_Craters.pdf].
C03a: Cook, C. M., H. J. Melosh, and W. F. Bottke Jr., 1996, Doublet craters on Venus, Icarus, 165:90-100. [http://www.boulder.swri.edu/~bottke/Reprints/Bottke_Binary_Icarus_1996.pdf].
C07a: Chapman, C. R., 2007, Implications for small-body binaries from doublet craters, 1st Workshop on Binaries in the Solar System. [http://www.boulder.swri.edu/clark/bincra07.ppt].
D12a: Dawn imagery [http://www.dawn.mps.mpg.de/index.php?id=17&L=1&tx_ttnews[tt_news]=122&cHash=d5cab4991de2c57eb1b44c24f494a4a2].
D98a: Richardson, D. C., W. F. Bottke Jr., and S. G. Love, 1998, Tidal distortion and disruption of Earth-crossing asteroids, Icarus, 134:47-76. [http://www.astro.umd.edu/~dcr/reprints/richardson_icarus134,47.pdf].
E12a: Earth Impact Database, Planetary and Space Science Centre, University of New Brunswick [http://www.passc.net/EarthImpactDatabase/index.html].
M07a: Mars Odyssey THEMIS imagery [http://photojournal.jpl.nasa.gov/catalog/PIA09162].
M10a: Mars Odyssey THEMIS imagery [http://photojournal.jpl.nasa.gov/catalog/PIA13738].
M11a: Mars Odyssey THEMIS imagery [http://photojournal.jpl.nasa.gov/catalog/PIA13850].
M12a: Milijkovic, K., G. S. Collins, S. Mannick, and P. A. Bland, 2012, Hydrocode simulations of binary asteroid impacts, LPSC, 43:1338. [http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1338.pdf].
M91a: Melosh, H. J., and J. Stansberry, 1991, Doublet craters and the tidal disruption of binary asteroids, Icarus, 94:171-179. [http://www.sciencedirect.com/science/article/pii/001910359190148M].
M96a: Melosh, H. J., J. Ingram, and W. F. Bottke Jr., 1996, The abundance of doublet craters on Mars, Lunar and Planetary Science, 27:863. [http://adsabs.harvard.edu/abs/1996LPI....27..863M].
T89a: Trego, K. D., 1989, Multiple impacts in the Earth's cratering history, Earth, Moon and Planets, 46:201-205. [http://articles.adsabs.harvard.edu//full/1989EM%26P...46..201T/0000201.000.html].

© 2002, 2012 by Wm. Robert Johnston.
Last modified 10 July 2012.
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