(152680) 1998 KJ9

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(152680) 1998 KJ9
Discovery [1]
Discovered by LINEAR (704)
1.0-m Reflector
Discovery site Lincoln Lab's ETS
Discovery date27 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° (ω)
Earth  MOID 0.00552 AU (826,000 km)
Physical characteristics
Dimensions ~500 meters [3]
Mass 7.87×1010 kg [4]
19.4 [2]

    (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]

    Contents

    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]

    History of close approaches of large near-Earth objects since 1908 (A)
    PHA DateApproach distance in lunar distances Abs. mag
    ( H )    		Diameter (C)
    (m)    		Ref (D)
    Nominal(B)MinimumMaximum
    (152680) 1998 KJ9 1914-12-310.6060.6040.60819.4279–900 data
    (458732) 2011 MD5 1918-09-170.9110.9090.91317.9556–1795 data
    (163132) 2002 CU11 1925-08-300.9030.9010.90518.5443–477 data
    69230 Hermes 1937-10-301.9261.9261.92717.5700-900 [10] data
    69230 Hermes1942-04-261.6511.6511.65117.5700-900 [10] data
    2017 NM6 1959-07-121.891.8461.93418.8580–1300 data
    (27002) 1998 DV9 1975-01-311.7621.7611.76218.1507–1637 data
    2002 NY40 2002-08-181.3711.3711.37119.0335–1082 data
    2004 XP14 2006-07-031.1251.1251.12519.3292–942 data
    2015 TB145 2015-10-311.2661.2661.26620.0620-690 data
    (137108) 1999 AN10 2027-08-071.0141.0101.01917.9556–1793 data
    (153814) 2001 WN5 2028-06-260.6470.6470.64718.2921–943 data
    99942 Apophis 2029-04-130.09810.09630.100019.7310–340 data
    2017 MB1 2072-07-261.2161.2152.75918.8367–1186 data
    2011 SM68 2072-10-171.8751.8651.88619.6254–820 data
    (163132) 2002 CU112080-08-311.6551.6541.65618.5443–477 data
    (416801) 1998 MZ 2116-11-261.0681.0681.06919.2305–986 data
    (153201) 2000 WO107 2140-12-010.6340.6310.63719.3427–593 data
    (276033) 2002 AJ129 2172-02-081.7831.7751.79218.7385–1242 data
    (290772) 2005 VC 2198-05-051.9511.7912.13417.6638–2061 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 AU≈390 LD)
    (E) Color codes:   unobserved at close approach  observed during close approach  upcoming approaches

    References

    1. 1 2 "MPEC 1998-K31 : 1998 KJ9". IAU Minor Planet Center. 29 May 1998. Archived from the original on 4 March 2016. Retrieved 15 November 2011. (J98K09J)
    2. 1 2 3 4 5 "JPL Small-Body Database Browser: 152680 (1998 KJ9)" (last observation: 2011-02-06; arc: 21.1 years). Jet Propulsion Laboratory . Retrieved 7 April 2016.
    3. 1 2 "Near Earth Asteroids (NEAs)" (Version 20.1). International Astronomical Union. 13 October 2011. Archived from the original on 21 January 2021. Retrieved 30 October 2011.
    4. ↑ "Asteroid General Data - 1998 KJ9 (152680)". Catalogue of the Solar System Small Bodies Orbital Evolution. Retrieved 15 November 2011.
    5. ↑ NEO Earth Close Approaches Archived 19 October 2017 at the Wayback Machine @ JPL CNEOS
      Select "Nominal dist <= 1 LD", "Past only", Sort by "H (mag)"
    6. 1 2 "(152680) = 1998 KJ9 Orbit" (2011-02-06; arc=7706 days). Minor Planet Center. Archived from the original on 4 March 2016. Retrieved 24 September 2013.
    7. ↑ "MPEC 2003-Y87 : 1998 KJ9". IAU Minor Planet Center. 29 December 2003. Archived from the original on 4 March 2016. Retrieved 24 September 2013.
    8. ↑ "JPL Close-Approach Data: 152680 (1998 KJ9)" (last observation: 2011-02-06; arc: 21.1 years). Archived from the original on 4 November 2020. Retrieved 15 November 2011.
    9. ↑ "1998KJ9 Ephemerides for 31 December 1914". NEODyS (Near Earth Objects - Dynamic Site). Archived from the original on 16 December 2024. Retrieved 15 November 2011.
    10. 1 2 Marchis, F.; et al. "Multiple asteroid systems: Dimensions and thermal properties from Spitzer Space Telescope and ground-based observations". Icarus. 221 (2): 1130–1161. Bibcode:2012Icar..221.1130M. doi:10.1016/j.icarus.2012.09.013 . Retrieved 24 August 2018.
    Preceded by
    		 Large NEO Earth close approach
    (inside the orbit of the Moon)
    31 December 1914    		Succeeded by
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