(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]

(7335) 1989 JA

Radar images of 1989 JA and its satellite, imaged by the Goldstone observatory in May 2022
Discovery[1]
Discovered by	E. F. Helin
Discovery site	Palomar Obs.
Discovery date	1 May 1989
Designations
MPC designation	(7335) 1989 JA
Alternative designations	1989 JA
Minor planet category	Apollo · NEO · PHA[1]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	27.98 yr (10,221 days)
Aphelion	2.6277 AU
Perihelion	0.9136 AU
Semi-major axis	1.7706 AU
Eccentricity	0.4840
Orbital period (sidereal)	2.36 yr (861 days)
Mean anomaly	341.87°
Mean motion	0° 25m 5.88s / day
Inclination	15.196°
Longitude of ascending node	61.325°
Argument of perihelion	232.24°
Earth MOID	0.0225 AU · 8.8 LD
Physical characteristics
Dimensions	0.932±0.153 km[2] 1.18 km (calculated)[3] 1.8 km (outdated)[1]
Synodic rotation period	<12 h[4]
Geometric albedo	0.20 (assumed)[3] 0.31±0.30[3][5] 0.322±0.150[2][6]
Spectral type	S[3]
Absolute magnitude (H)	17.0[1][2][3] · 17.8±0.3[7]

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

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• (7335) 1989 JA at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
• (7335) 1989 JA at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical Properties · Summary
• (7335) 1989 JA at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters