(7335) 1989 JA
Radar images of 1989 JA and its satellite, imaged by the Goldstone observatory in May 2022
Discovery[1]
Discovered byE. F. Helin
Discovery sitePalomar Obs.
Discovery date1 May 1989
Designations
(7335) 1989 JA
1989 JA
Apollo · NEO · PHA[1]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc27.98 yr (10,221 days)
Aphelion2.6277 AU
Perihelion0.9136 AU
1.7706 AU
Eccentricity0.4840
2.36 yr (861 days)
341.87°
0° 25m 5.88s / day
Inclination15.196°
61.325°
232.24°
Earth MOID0.0225 AU · 8.8 LD
Physical characteristics
Dimensions0.932±0.153 km[2]
1.18 km (calculated)[3]
1.8 km (outdated)[1]
<12 h[4]
0.20 (assumed)[3]
0.31±0.30[3][5]
0.322±0.150[2][6]
S[3]
17.0[1][2][3] · 17.8±0.3[7]

    (7335) 1989 JA, provisional designation 1989 JA, is a stony asteroid of the Apollo group, classified as near-Earth object and potentially hazardous asteroid, approximately 1 kilometer in diameter. It was discovered on 1 May 1989, by American astronomer Eleanor Helin at the U.S. Palomar Observatory in California.[8] On 27 May 2022, the asteroid made a close approach 0.027 astronomical units (4.0×10^6 km; 2.5×10^6 mi) from Earth. During the close approach, optical observations detected signs of an orbiting satellite, which was later confirmed by radar imaging at NASA's Goldstone Solar System Radar in California.[9]

    2022 close approach[1]
    Date JPL SBDB
    nominal geocentric
    distance    		 uncertainty
    region
    (3-sigma)
    2022-05-274024703 km± 153 km

    Orbit and classification

    The S-type asteroid orbits the Sun at a distance of 0.9–2.6 AU once every 2 years and 4 months (861 days). Its orbit has an eccentricity of 0.48 and an inclination of 15° with respect to the ecliptic.[1] The first observation was made at the discovering observatory in April 1989, extending the asteroid's observation arc by 1 month prior to its discovery observation.[8] It has a minimum orbital intersection distance to Earth of 0.0225 AU (3,370,000 km) which corresponds to 8.8 lunar distances.[1]

    Physical characteristics

    During its discovery in May 1989, radiometric observations for this asteroid at Arecibo and Goldstone Observatory rendered a rotation period of less than 12 hours (U=n.a.).[4] According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid measures 0.93 kilometers in diameter and its surface has a high albedo of 0.31–0.32,[2][5][6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.18 kilometers, based on an absolute magnitude of 17.0.[3]

    Naming

    As of 2022, 1989 JA remains unnamed.[8]

    References

    1. 1 2 3 4 5 6 7 8 "JPL Small-Body Database Browser: 7335 (1989 JA)" (2017-03-31 last obs.). Jet Propulsion Laboratory. Retrieved 26 May 2017.
    2. 1 2 3 4 Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
    3. 1 2 3 4 5 6 "LCDB Data for (7335)". Asteroid Lightcurve Database (LCDB). Retrieved 26 September 2016.
    4. 1 2 Mahapatra, Pravas R.; Benner, Lance A. M.; Ostro, Steven J.; Jurgens, Raymond F.; Giorgini, Jon D.; Yeomans, Donald K.; et al. (March 2002). "Radar observations of asteroid 7335 ( 1989 JA)". Planetary and Space Science. 50 (3): 257–260. Bibcode:2002P&SS...50..257M. doi:10.1016/S0032-0633(02)00002-8. Retrieved 26 September 2016.
    5. 1 2 Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Wright, E.; Cutri, R. M.; et al. (August 2011). "Thermal Model Calibration for Minor Planets Observed with Wide-field Infrared Survey Explorer/NEOWISE". The Astrophysical Journal. 736 (2): 9. Bibcode:2011ApJ...736..100M. CiteSeerX 10.1.1.472.4936. doi:10.1088/0004-637X/736/2/100. Retrieved 26 September 2016.
    6. 1 2 Mainzer, A.; Grav, T.; Bauer, J.; Masiero, J.; McMillan, R. S.; Cutri, R. M.; et al. (December 2011). "NEOWISE Observations of Near-Earth Objects: Preliminary Results". The Astrophysical Journal. 743 (2): 17. arXiv:1109.6400. Bibcode:2011ApJ...743..156M. doi:10.1088/0004-637X/743/2/156. Retrieved 26 September 2016.
    7. ↑ Wisniewski, W. Z.; Michalowski, T. M.; Harris, A. W.; McMillan, R. S. (March 1995). "Photoelectric Observations of 125 Asteroids". Abstracts of the Lunar and Planetary Science Conference. 26: 1511. Bibcode:1995LPI....26.1511W. Retrieved 26 September 2016.
    8. 1 2 3 "7335 (1989 JA)". Minor Planet Center. Retrieved 26 September 2016.
    9. ↑ Benner, Lance A. M. "Goldstone Radar Observations Planning: (7335) 1989 JA, 388945 2008 TZ3, and 467460 2006 JF42". Asteroid Radar Research. Jet Propulsion Laboratory. Retrieved 15 June 2022.
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