Roaming Astronomer: Near-Earth Objects, Part Six

Near-Earth Asteroid Discovery Statistics

Data Compiled by Alan B. Chamberlin of NASA/Jet Propulsion Laboratory

The charts and tables below show the number of near-Earth asteroids (NEAs) discovered by each of the predominant search programs within each half-year interval. There are two sets of charts and tables. The first set shows statistics for all NEAs while the second set shows statistics for only large NEAs. In this context, "large" is defined as NEAs with absolute magnitudes (H) of 18.0 or brighter. This roughly corresponds to 1 km diameter and larger NEAs.

All Asteroids

NEAs Discovered by Site

Half Year Intervals	LINEAR (704)	NEAT (566,608,644)	Spacewatch (691,291)	LONEOS (699)	Catalina (703,E12,G96)	Pan-STARRS (F51)	Other	Cumulative Total
1995 (1)	0	0	14	0	0	0	4	334
1995 (2)	0	0	12	0	0	0	2	348
1996 (1)	1	5	18	0	0	0	4	376
1996 (2)	0	5	10	0	0	0	2	393
1997 (1)	3	2	10	0	0	0	4	412
1997 (2)	14	9	4	0	0	0	7	446
1998 (1)	44	9	19	1	1	0	7	527
1998 (2)	92	2	16	6	2	0	5	650
1999 (1)	74	0	12	6	11	0	1	754
1999 (2)	87	0	7	7	19	0	3	877
2000 (1)	108	2	14	21	13	0	4	1039
2000 (2)	150	13	12	17	0	0	8	1239
2001 (1)	95	28	7	22	0	0	2	1393
2001 (2)	184	64	15	20	0	0	4	1680
2002 (1)	158	56	16	14	1	0	6	1931
2002 (2)	128	89	6	7	0	0	5	2166
2003 (1)	102	30	23	33	0	0	9	2363
2003 (2)	133	38	33	21	8	0	8	2604
2004 (1)	167	19	41	14	25	0	6	2876
2004 (2)	137	7	29	25	60	0	6	3140
2005 (1)	78	8	28	22	116	0	10	3402
2005 (2)	59	30	54	19	193	0	10	3767
2006 (1)	44	4	45	13	197	0	3	4073
2006 (2)	52	18	54	7	200	0	5	4409
2007 (1)	38	4	20	7	200	0	3	4681
2007 (2)	74	0	25	5	266	0	7	5058
2008 (1)	74	0	43	1	281	0	5	5462
2008 (2)	67	0	43	0	278	0	11	5861
2009 (1)	50	0	32	0	262	0	18	6223
2009 (2)	58	0	31	0	314	0	17	6643
2010 (1)	29	0	21	0	257	0	98	7048
2010 (2)	75	0	22	0	345	18	52	7560
2011 (1)	40	0	17	0	333	68	14	8032
2011 (2)	30	0	15	0	253	105	23	8458
2012 (1)*	19	0	12	0	266	91	4	8850

* Incomplete half-year (based on discovery data through 2012-Apr-29 06:05 local)

Large Asteroids

Large NEAs Discovered by Site

Half Year Intervals	LINEAR (704)	NEAT (566,608,644)	Spacewatch (691,291)	LONEOS (699)	Catalina (703,E12,G96)	Other	Cumulative Total
1995 (1)	0	0	3	0	0	2	192
1995 (2)	0	0	4	0	0	1	197
1996 (1)	0	2	2	0	0	0	201
1996 (2)	0	2	0	0	0	0	203
1997 (1)	0	1	3	0	0	1	208
1997 (2)	3	4	1	0	0	2	218
1998 (1)	9	4	2	1	0	2	236
1998 (2)	27	2	1	3	0	3	272
1999 (1)	21	0	2	5	4	0	304
1999 (2)	27	0	1	2	3	2	339
2000 (1)	35	2	2	2	5	1	386
2000 (2)	43	2	3	6	0	4	444
2001 (1)	28	10	0	5	0	0	487
2001 (2)	31	10	0	5	0	1	534
2002 (1)	41	5	2	3	0	3	588
2002 (2)	26	15	0	1	0	2	632
2003 (1)	19	4	2	6	0	1	664
2003 (2)	21	6	2	4	2	1	700
2004 (1)	18	5	1	2	4	1	731
2004 (2)	10	1	0	1	14	0	757
2005 (1)	13	1	2	1	11	1	786
2005 (2)	6	8	5	2	12	1	820
2006 (1)	3	0	2	1	11	1	838
2006 (2)*	0	0	0	0	1	0	839

* Incomplete half-year (based on discovery data through 2006-Jul-07 06:00 local)

Number of NEOs

NASA's search program designed to discover 90% of the NEO population (1 km in diameter or larger) within 10 years is under way. The chart below shows the cumulative total known near-Earth asteroids versus time. The blue area shows all near-Earth asteroids while the red area shows only large near-Earth asteroids (those with diameters roughly one kilometer and larger).

The chart below shows the total known near-Earth asteroids per size bin. Diameters are estimated using an assumed average albedo for NEAs. The first size bin represents NEAs smaller than 30m in diameter. The second represents NEAs with diameters from 30m to 100m, and so on. Data shown in the chart represent known NEAs as of the date shown in the bottom-right corner of the chart.

The table below shows the total number of NEOs known at selected dates. The most recent date at the top of the table is generally not the date the table was updated, but rather the discovery date of the most recently discovered NEO. This table is updated daily using discovery data published by the Minor Planet Center. "NEC" are Near-Earth comets. "PHA-KM" and "NEA-KM" are PHAs and NEAs with diameters roughly one kilometer and larger. Other definitions, such as Apollo, are on the NEO groups page.

------------------------------------------------------------------------
Date NEC Atira Aten Apollo Amor PHA-KM PHA NEA-KM NEA NEO
---------- ---- ----- ---- ------ ---- ------ ---- ------ ---- ----
2012-04-27 91 11 702 4811 3326 152 1303 840 8850 8941
2012-04-01 91 11 701 4770 3302 152 1299 839 8784 8875
2012-03-01 91 11 695 4690 3275 152 1292 838 8671 8762
2012-02-01 91 11 686 4642 3234 152 1285 838 8573 8664
2012-01-01 91 11 676 4572 3199 152 1277 837 8458 8549
2011-12-01 91 11 672 4540 3174 152 1270 833 8397 8488
2011-11-01 91 11 669 4499 3139 150 1260 830 8318 8409
2011-10-01 91 11 662 4437 3094 149 1248 829 8204 8295
2011-09-01 90 11 661 4402 3039 149 1242 827 8113 8203
2011-08-01 90 11 661 4386 3013 149 1239 826 8071 8161
2011-07-01 89 11 659 4373 2989 149 1235 826 8032 8121
2011-06-01 89 11 659 4356 2963 149 1230 825 7989 8078
2011-05-01 89 11 656 4329 2942 149 1220 824 7938 8027
2011-04-01 89 11 645 4279 2912 149 1213 823 7847 7936
2011-03-01 89 11 634 4216 2888 149 1203 821 7749 7838
2011-02-01 89 11 624 4169 2870 149 1192 821 7674 7763
2011-01-01 89 11 618 4093 2838 149 1176 819 7560 7649
2010-12-01 89 10 609 4038 2806 149 1167 818 7463 7552
2010-11-01 89 10 598 3969 2760 149 1161 818 7337 7426
2010-10-01 89 10 588 3913 2720 149 1147 818 7231 7320
2010-09-01 89 10 582 3867 2655 149 1142 817 7114 7203
2010-08-01 89 10 579 3853 2645 149 1139 815 7087 7176
2010-07-01 89 10 574 3831 2633 149 1137 813 7048 7137
2010-06-01 88 10 568 3800 2610 149 1129 812 6988 7076
2010-05-01 87 10 560 3757 2590 148 1116 810 6917 7004
2010-04-01 87 10 552 3710 2574 148 1110 810 6846 6933
2010-03-01 87 10 544 3673 2549 148 1101 810 6776 6863
2010-02-01 87 10 540 3619 2524 147 1089 808 6693 6780
2010-01-01 87 10 535 3593 2505 147 1086 806 6643 6730
2009-12-01 87 10 531 3572 2495 147 1081 804 6608 6695
2009-11-01 86 10 520 3496 2467 147 1073 801 6493 6579
2009-10-01 86 10 511 3441 2434 147 1069 799 6396 6482
2009-09-01 86 10 506 3388 2387 147 1059 797 6291 6377
2009-08-01 86 10 504 3368 2360 147 1057 796 6242 6328
2009-07-01 86 10 504 3358 2351 146 1055 792 6223 6309
2009-06-01 85 10 501 3345 2341 145 1052 791 6197 6282
2009-05-01 85 10 499 3318 2328 145 1043 790 6155 6240
2009-04-01 85 10 496 3286 2314 145 1039 788 6106 6191
2009-03-01 85 10 491 3224 2295 145 1027 788 6020 6105
2009-02-01 85 10 487 3167 2268 144 1015 785 5932 6017
2009-01-01 85 10 481 3122 2248 144 1006 783 5861 5946
2008-12-01 84 10 480 3080 2218 144 996 782 5788 5872
2008-11-01 84 10 474 3032 2196 144 987 780 5712 5796
2008-10-01 84 9 467 2971 2146 143 977 779 5593 5677
2008-09-01 83 9 464 2940 2112 143 967 778 5525 5608
2008-08-01 83 9 461 2925 2098 143 961 777 5493 5576
2008-07-01 83 9 459 2907 2087 142 952 774 5462 5545
2008-06-01 83 9 455 2896 2079 142 949 773 5439 5522
2008-05-01 83 9 451 2866 2062 142 943 773 5388 5471
2008-04-01 83 9 449 2819 2033 142 940 772 5310 5393
2008-03-01 83 8 440 2751 2008 141 930 765 5207 5290
2008-02-01 83 8 428 2692 1977 140 916 763 5105 5188
2008-01-01 83 8 426 2664 1960 140 907 763 5058 5141
2007-12-01 83 8 423 2629 1943 140 898 760 5003 5086
2007-11-01 83 8 411 2571 1907 140 888 756 4897 4980
2007-10-01 82 8 397 2522 1865 140 877 755 4792 4874
2007-09-01 82 8 390 2484 1833 139 870 754 4715 4797
2007-08-01 82 8 388 2473 1823 138 865 750 4692 4774
2007-07-01 82 8 388 2469 1816 138 864 750 4681 4763
2007-06-01 82 8 383 2447 1807 137 855 747 4645 4727
2007-05-01 82 8 382 2435 1795 137 851 745 4620 4702
2007-04-01 82 8 381 2410 1778 137 847 741 4577 4659
2007-03-01 82 7 375 2371 1754 137 840 739 4507 4589
2007-02-01 82 7 367 2338 1738 136 832 735 4450 4532
2007-01-01 82 7 359 2318 1725 136 823 734 4409 4491
2006-12-01 81 7 354 2291 1707 136 820 732 4359 4440
2006-11-01 81 6 344 2242 1683 135 808 725 4275 4356
2006-10-01 79 6 337 2212 1651 135 798 723 4206 4285
2006-09-01 79 6 330 2176 1622 134 789 719 4134 4213
2006-08-01 79 6 328 2159 1609 134 784 719 4102 4181
2006-07-01 79 6 327 2148 1592 134 782 718 4073 4152
2006-06-01 79 6 326 2137 1579 134 779 718 4048 4127
2006-05-01 79 5 325 2109 1552 134 769 714 3991 4070
2006-04-01 78 5 321 2082 1537 134 759 712 3945 4023
2006-03-01 78 5 319 2066 1518 134 758 711 3908 3986
2006-02-01 78 5 316 2031 1501 134 750 708 3853 3931
2006-01-01 78 5 312 1976 1474 133 741 703 3767 3845
2005-12-01 78 5 302 1944 1453 132 730 700 3704 3782
2005-11-01 77 5 297 1902 1427 131 720 695 3631 3708
2005-10-01 76 4 289 1846 1387 130 708 684 3526 3602
2005-09-01 76 4 286 1812 1368 130 703 681 3470 3546
2005-08-01 76 4 283 1798 1352 130 697 679 3437 3513
2005-07-01 76 4 279 1779 1340 129 690 676 3402 3478
2005-06-01 76 4 275 1764 1320 129 686 671 3363 3439
2005-05-01 75 4 274 1747 1305 127 680 668 3330 3405
2005-04-01 75 4 268 1722 1286 125 667 664 3280 3355
2005-03-01 75 4 263 1681 1262 124 657 660 3210 3285
2005-02-01 75 4 262 1657 1255 123 653 657 3178 3253
2005-01-01 75 4 258 1633 1245 123 646 653 3140 3215
2004-12-01 74 3 249 1601 1224 123 637 645 3077 3151
2004-11-01 74 3 245 1581 1218 122 628 640 3047 3121
2004-10-01 73 3 238 1553 1210 121 617 638 3004 3077
2004-09-01 72 3 230 1515 1185 121 609 637 2933 3005
2004-08-01 72 3 226 1496 1162 120 602 633 2887 2959
2004-07-01 72 3 226 1490 1157 118 599 630 2876 2948
2004-06-01 72 3 223 1460 1144 117 588 627 2830 2902
2004-05-01 72 2 218 1441 1129 117 582 623 2790 2862
2004-04-01 72 2 215 1411 1117 113 572 616 2745 2817
2004-03-01 72 2 206 1375 1099 113 565 607 2682 2754
2004-02-01 71 2 204 1360 1092 112 560 606 2658 2729
2004-01-01 71 2 202 1326 1074 110 550 602 2604 2675
2003-12-01 71 2 196 1294 1062 107 538 594 2554 2625
2003-11-01 71 2 193 1272 1049 107 530 588 2516 2587
2003-10-01 71 2 188 1245 1027 107 521 586 2462 2533
2003-09-01 71 2 185 1225 993 105 512 579 2405 2476
2003-08-01 71 2 185 1213 980 102 507 575 2380 2451
2003-07-01 70 2 184 1206 971 102 504 572 2363 2433
2003-06-01 70 2 182 1190 959 102 499 566 2333 2403
2003-05-01 68 2 180 1176 953 101 497 564 2311 2379
2003-04-01 68 2 175 1156 942 101 490 559 2275 2343
2003-03-01 68 2 170 1137 931 101 483 555 2240 2308
2003-02-01 68 1 169 1117 925 101 478 551 2212 2280
2003-01-01 68 1 167 1090 908 100 468 544 2166 2234
2002-12-01 68 1 163 1063 888 100 466 542 2115 2183
2002-11-01 68 1 160 1048 871 99 460 538 2080 2148
2002-10-01 67 1 158 1024 848 98 454 529 2031 2098
2002-09-01 65 1 155 1004 829 97 448 521 1989 2054
2002-08-01 65 1 154 988 806 95 437 517 1949 2014
2002-07-01 64 1 152 978 800 94 430 512 1931 1995
2002-06-01 64 1 148 960 792 92 421 506 1901 1965
2002-05-01 64 1 144 942 781 91 412 495 1868 1932
2002-04-01 64 1 142 924 768 91 405 493 1835 1899
2002-03-01 63 1 136 897 754 90 395 489 1788 1851
2002-02-01 63 1 131 874 738 89 386 479 1744 1807
2002-01-01 63 1 124 840 715 89 373 470 1680 1743
2001-12-01 63 1 121 804 696 85 359 461 1622 1685
2001-11-01 61 1 120 776 681 83 351 456 1578 1639
2001-10-01 61 1 114 750 658 82 341 452 1523 1584
2001-09-01 61 1 110 721 623 81 330 439 1455 1516
2001-08-01 60 1 109 699 603 81 324 437 1412 1472
2001-07-01 59 1 108 694 590 81 323 436 1393 1452
2001-06-01 58 1 108 684 579 79 320 429 1372 1430
2001-05-01 57 1 107 672 568 77 313 421 1348 1405
2001-04-01 57 1 105 660 559 76 304 417 1325 1382
2001-03-01 57 1 101 645 545 74 295 409 1292 1349
2001-02-01 57 1 98 634 534 73 292 404 1267 1324
2001-01-01 57 1 94 619 525 73 289 400 1239 1296
2000-12-01 57 1 93 605 513 72 283 393 1212 1269
2000-11-01 57 1 90 581 496 71 280 384 1168 1225
2000-10-01 57 1 87 571 482 71 276 376 1141 1198
2000-09-01 57 1 81 553 456 70 270 367 1091 1148
2000-08-01 57 1 79 535 440 68 261 358 1055 1112
2000-07-01 57 1 77 530 431 66 258 347 1039 1096
2000-06-01 57 1 76 525 425 65 254 344 1027 1084
2000-05-01 57 1 76 512 411 65 249 338 1000 1057
2000-04-01 56 1 73 497 398 64 243 331 969 1025
2000-03-01 56 1 64 481 387 62 231 319 933 989
2000-02-01 56 1 62 464 376 62 221 312 903 959
2000-01-01 56 1 57 450 369 62 215 307 877 933
1999-12-01 55 1 56 440 360 60 207 299 857 912
1999-11-01 55 1 54 427 346 60 203 289 828 883
1999-10-01 55 1 54 411 332 59 198 284 798 853
1999-09-01 53 1 54 394 317 58 192 280 766 819
1999-08-01 53 1 54 394 315 58 192 280 764 817
1999-07-01 53 1 54 389 310 57 190 276 754 807
1999-06-01 53 1 51 382 300 56 185 273 734 787
1999-05-01 52 1 49 370 295 52 177 264 715 767
1999-04-01 52 1 48 357 288 51 173 256 694 746
1999-03-01 52 1 47 347 283 51 172 255 678 730
1999-02-01 52 1 47 337 278 51 169 252 663 715
1999-01-01 52 1 45 332 272 51 166 250 650 702
1998-12-01 52 1 41 322 263 51 162 241 627 679
1998-11-01 52 1 38 307 254 49 154 236 600 652
1998-10-01 52 1 36 302 248 49 152 232 587 639
1998-09-01 52 1 29 289 235 48 140 226 554 606
1998-08-01 52 1 29 279 224 46 133 220 533 585
1998-07-01 52 1 29 276 221 44 129 217 527 579
1998-06-01 52 1 29 270 214 43 127 213 514 566
1998-05-01 52 1 29 261 208 43 124 209 499 551
1998-04-01 52 1 27 253 199 43 117 208 480 532
1998-03-01 52 1 27 242 190 43 112 204 460 512
1998-02-01 52 0 26 238 190 42 110 203 454 506
1998-01-01 52 0 26 233 187 42 108 200 446 498
1997-01-01 52 0 22 204 167 40 97 188 393 445
1996-01-01 52 0 20 177 151 38 86 182 348 400
1995-01-01 52 0 19 163 134 37 83 172 316 368
1994-01-01 50 0 15 140 115 33 70 155 270 320
1993-01-01 50 0 13 117 99 31 64 141 229 279
1992-01-01 50 0 11 103 85 29 61 124 199 249
1991-01-01 48 0 9 76 74 24 49 106 159 207
1990-01-01 48 0 8 63 63 20 42 90 134 182
1980-01-01 44 0 3 27 23 12 17 45 53 97
1970-01-01 42 0 0 13 14 8 10 24 27 69
1960-01-01 41 0 0 10 10 7 8 18 20 61
1950-01-01 41 0 0 7 6 4 5 12 13 54
1940-01-01 36 0 0 3 6 2 3 8 9 45
1930-01-01 34 0 0 0 5 0 0 5 5 39
1920-01-01 32 0 0 0 3 0 0 3 3 35
1910-01-01 30 0 0 0 1 0 0 1 1 31
1900-01-01 28 0 0 0 1 0 0 1 1 29

To be continued...

NASA's Near-Earth Object (NEO) Program coordinates NASA-sponsored efforts to detect, track and characterize potentially hazardous asteroids and comets that could approach the Earth. To learn more, visit the home page of NASA's Near-Earth Object Program: http://neo.jpl.nasa.gov/

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Roaming Astronomer

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Monday, April 30, 2012

Near-Earth Objects, Part Six

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