(152680) 1998 KJ9
Small near-Earth asteroid
From Wikipedia, the free encyclopedia
(152680) 1998 KJ9 is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group.[2] Based on absolute magnitude, it is the third largest asteroid known to have passed closer than the Moon.[5]
| Discovery[1] | |
|---|---|
| Discovered by | LINEAR (704) 1.0-m Reflector |
| Discovery site | Lincoln Lab's ETS |
| Discovery date | 27 May 1998 |
| Designations | |
| (152680) 1998 KJ9 | |
| NEO · PHA · Apollo[2] | |
| Orbital characteristics[2] | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 7706 days (21.10 yr) |
| Aphelion | 2.3742 AU (355.18 Gm) (Q) |
| Perihelion | 0.52125 AU (77.978 Gm) (q) |
| 1.4477 AU (216.57 Gm) (a) | |
| Eccentricity | 0.63995 (e) |
| 1.74 yr (636.25 d) | |
| 6.2670° (M) | |
| 0° 33m 56.952s / day (n) | |
| Inclination | 10.932° (i) |
| 98.675° (Ω) | |
| 259.95° (Ï) | |
| Earth MOID | 0.00552 AU (826,000 km) |
| Physical characteristics | |
| Dimensions | ~500 meters[3] |
| Mass | 7.87Ã1010 kg[4] |
| 19.4[2] | |
Description
It was discovered on 27 May 1998, by astronomers of the Lincoln Near-Earth Asteroid Research (LINEAR) at Lincoln Laboratory's ETS near Socorro, New Mexico, at an apparent magnitude of 17.6 using a 1.0-meter (39 in) reflector.[1] It was tracked through 9 June 1998.[6] It was recovered on 28 December 2003 which extended the observation arc by 5 years.[7] Two precovery images from January 1990 extended the observation arc by 8 years.[6]
Based on an absolute magnitude of 19.4,[2] the asteroid has an estimated diameter of about 500 metres (1,600 ft).[3] (152680) 1998 KJ9 is noted for a close approach to the Earth on 31 December 1914 at a distance of 0.00155 AU (232,000 km; 144,000 mi).[8] It is one of the largest objects known to have come inside the orbit of the moon. During the 1914 close approach the asteroid reached about apparent magnitude 7.7.[9]
| PHA | Date | Approach distance in lunar distances | Abs. mag (H) |
Diameterâ(C) (m) |
Refâ(D) | ||
|---|---|---|---|---|---|---|---|
| Nominal(B) | Minimum | Maximum | |||||
| (152680) 1998 KJ9 | 1914-12-31 | 0.606 | 0.604 | 0.608 | 19.4 | 279â900 | data |
| (458732) 2011 MD5 | 1918-09-17 | 0.911 | 0.909 | 0.913 | 17.9 | 556â1795 | data |
| (163132) 2002 CU11 | 1925-08-30 | 0.903 | 0.901 | 0.905 | 18.5 | 443â477 | data |
| 69230 Hermes | 1937-10-30 | 1.926 | 1.926 | 1.927 | 17.5 | 700-900[10] | data |
| 69230 Hermes | 1942-04-26 | 1.651 | 1.651 | 1.651 | 17.5 | 700-900[10] | data |
| 2017 NM6 | 1959-07-12 | 1.89 | 1.846 | 1.934 | 18.8 | 580â1300 | data |
| (27002) 1998 DV9 | 1975-01-31 | 1.762 | 1.761 | 1.762 | 18.1 | 507â1637 | data |
| 2002 NY40 | 2002-08-18 | 1.371 | 1.371 | 1.371 | 19.0 | 335â1082 | data |
| 2004 XP14 | 2006-07-03 | 1.125 | 1.125 | 1.125 | 19.3 | 292â942 | data |
| 2015 TB145 | 2015-10-31 | 1.266 | 1.266 | 1.266 | 20.0 | 620-690 | data |
| (137108) 1999 AN10 | 2027-08-07 | 1.014 | 1.010 | 1.019 | 17.9 | 556â1793 | data |
| (153814) 2001 WN5 | 2028-06-26 | 0.647 | 0.647 | 0.647 | 18.2 | 921â943 | data |
| 99942 Apophis | 2029-04-13 | 0.0981 | 0.0963 | 0.1000 | 19.7 | 310â340 | data |
| 2017 MB1 | 2072-07-26 | 1.216 | 1.215 | 2.759 | 18.8 | 367â1186 | data |
| 2011 SM68 | 2072-10-17 | 1.875 | 1.865 | 1.886 | 19.6 | 254â820 | data |
| (163132) 2002 CU11 | 2080-08-31 | 1.655 | 1.654 | 1.656 | 18.5 | 443â477 | data |
| (416801) 1998 MZ | 2116-11-26 | 1.068 | 1.068 | 1.069 | 19.2 | 305â986 | data |
| (153201) 2000 WO107 | 2140-12-01 | 0.634 | 0.631 | 0.637 | 19.3 | 427â593 | data |
| (276033) 2002 AJ129 | 2172-02-08 | 1.783 | 1.775 | 1.792 | 18.7 | 385â1242 | data |
| (290772) 2005 VC | 2198-05-05 | 1.951 | 1.791 | 2.134 | 17.6 | 638â2061 | data |
| (A) This list includes near-Earth approaches of less than 2 lunar distances (LD) of objects with H brighter than 20. (B) Nominal geocentric distance from the center of Earth to the center of the object (Earth has a radius of approximately 6,400 km). (C) Diameter: estimated, theoretical mean-diameter based on H and albedo range between X and Y. (D) Reference: data source from the JPL SBDB, with AU converted into LD (1 AUâ390 LD) (E) Color codes: unobserved at close approach observed during close approach upcoming approaches | |||||||
