(7335) 1989 JA
A potentially hazardous binary asteroid discovered in 1989.
(7335) 1989 JA belongs to the Apollo group of stony asteroids and is categorized as both a near-Earth object and a potentially hazardous one, with a diameter of roughly one kilometer. American astronomer Eleanor Helin discovered it on May 1, 1989, using the Palomar Observatory in California. The asteroid gained attention when it passed close to Earth on May 27, 2022, coming within 0.027 astronomical units (about 4 million kilometers or 2.5 million miles). During this approach, optical observations hinted at a moon orbiting the asteroid, and later radar imaging from NASA's Goldstone Solar System Radar in California confirmed it, revealing a binary system.
The asteroid follows an orbit around the Sun that ranges from 0.9 to 2.6 AU, completing one circuit every 861 days (roughly 2 years and 4 months). Its orbit has an eccentricity of 0.48 and an inclination of 15 degrees relative to the ecliptic. The first recorded observation came from the discovering observatory in April 1989, extending the known observation arc by one month before the official discovery. Its minimum orbital intersection distance with Earth is 0.0225 AU (about 3.37 million kilometers), equivalent to 8.8 lunar distances.
Physical data gathered during its discovery in May 1989, using radiometric observations at Arecibo and Goldstone, indicated a rotation period of less than 12 hours. According to NASA's NEOWISE survey, the asteroid measures 0.93 kilometers in diameter with a high surface albedo between 0.31 and 0.32. The Collaborative Asteroid Lightcurve Link, assuming a standard albedo of 0.20 for stony asteroids and an absolute magnitude of 17.0, calculates a diameter of 1.18 kilometers.
As of 2022, the asteroid has not been assigned a name.
Quick Facts
- Minorplanet
- yes
- Background
- #FFC2E0
- Discovered
- 1 May 1989
- Discoverer
- E. F. Helin
- Discovery Site
- Palomar Obs.
- Mpc Name
- (7335) 1989 JA
- Mp Category
- ApolloNEOPHA
- Epoch
- 4 September 2017 (JD 2458000.5)
- Uncertainty
- 0
- Observation Arc
- 27.98 yr (10,221 days)
- Aphelion
- 2.6277 AU
- Perihelion
- 0.9136 AU
Facts from the source article.
Lore & Background
The asteroid orbits the Sun at a distance of 0.9–2.6 AU once every 861 days, with an eccentricity of 0.48 and an inclination of 15° to the ecliptic. Its first observation was made at the discovering observatory in April 1989, extending the observation arc by one month prior to its discovery. It has a minimum orbital intersection distance to Earth of 0.0225 AU, equivalent to 8.8 lunar distances.
During its discovery in May 1989, radiometric observations at Arecibo and Goldstone Observatory indicated a rotation period of less than 12 hours. The NEOWISE mission measured a diameter of 0.93 kilometers with a high albedo of 0.31–0.32, while the Collaborative Asteroid Lightcurve Link, assuming a standard albedo of 0.20 for stony asteroids, calculates a diameter of 1.18 kilometers based on an absolute magnitude of 17.0. As of 2022, the asteroid remains unnamed.
Reader's Guide
The significance of (7335) 1989 JA lies in its classification as a potentially hazardous asteroid and its confirmed binary nature. On 27 May 2022, it made a close approach of 0.027 astronomical units (4.0×10⁶ km) from Earth. During this approach, optical observations detected signs of an orbiting satellite, later confirmed by radar imaging at NASA's Goldstone Solar System Radar. This discovery adds to the understanding of binary asteroid systems among near-Earth objects. The asteroid's physical characteristics, including its stony composition and diameter estimates from different surveys (0.93 km from NEOWISE versus 1.18 km from lightcurve analysis), highlight the uncertainties in asteroid size determination. Its orbit, with an eccentricity of 0.48 and inclination of 15°, brings it relatively close to Earth's orbit, making it a target for continued monitoring and study. The fact that it remains unnamed as of 2022 underscores the routine nature of such discoveries in the context of minor planet nomenclature.
Did You Know?
- It was discovered on 1 May 1989 by American astronomer Eleanor Helin at Palomar Observatory.
- On 27 May 2022, it made a close approach of 0.027 AU from Earth, during which a satellite was detected and confirmed by radar.
- As of 2022, (7335) 1989 JA remains unnamed.
More in Notable Asteroids, Part 3 1-24
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