| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin |
| Discovery site | Palomar Obs. |
| Discovery date | 4 July 1973 |
| Designations | |
| (5496) 1973 NA | |
| 1973 NA · 1992 OA | |
| Apollo · NEO[2] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 41.30 yr (15,086 days) |
| Aphelion | 3.9837AU |
| Perihelion | 0.8865 AU |
| 2.4351 AU | |
| Eccentricity | 0.6360 |
| 3.80yr (1,388 days) | |
| 240.93° | |
| 0° 15m 33.84s / day | |
| Inclination | 68.006° |
| 101.04° | |
| 118.02° | |
| Earth MOID | 0.0904 AU |
| Physical characteristics | |
| 1.88 km(calculated)[3] | |
| 2.855±0.001h[a] | |
| 0.20(assumed)[3] | |
| C/X[4] · S[3] | |
| 16.0[1][3] | |
(5496) 1973 NA, is a very eccentric and heavily tiltedasteroid, classified asnear-Earth object of theApollo group, approximately 2 kilometers in diameter. It was discovered on 4 July 1973, by American astronomerEleanor Helin at the U.S.Palomar Observatory in California.[2] At the time of its discovery, it was themost highly inclined minor planet known to exist. It may be the parent body of theQuadrantids.
1973 NA is a possible parent body of theQuadrantids, a majormeteor shower that occurs every January. It may also be just a fragment of the parent or the dormant remains of the parent. Other possible parent bodies areComet 1491 I and comet96P/Machholz,[5] as well as(196256) 2003 EH1.[6][7]
The asteroid orbits the Sun at a distance of 0.9–4.0 AU once every 3 years and 10 months (1,388 days). Its orbit has aneccentricity of 0.64 and aninclination of 68° with respect to theecliptic.[1] Noprecoveries were taken. The asteroid'sobservation arc even begins 2 days after its discovery.[2]
The body was also one of the first known near-Earth asteroids. Its discovery happened just two days after it had passed 0.07984 AU (11,900,000 km) from Earth on one of its closest approaches ever computed.[8] It was then tracked for more than a month, but was not seen again until its next close approach in 1992, when it was recovered by theSiding Spring Observatory in Australia.[2] Itsminimum orbit intersection distance with Earth is now 0.0904 AU (13,500,000 km).[1]
The stonyS-type asteroid is also classified as a transitional C/X-type according to observations by theNASA IRTF telescope.[4] A rotationallightcurve for this asteroid was obtained by American astronomerBrian Skiff from photometric observations made in June 2011. Lightcurve analysis gave a well-definedrotation period of2.855±0.001 hours with a brightness variation of 0.15magnitude (U=3).[a] TheCollaborative Asteroid Lightcurve Link assumes a standardalbedo for stony asteroids of 0.20 and calculates a diameter of 1.88 kilometers with anabsolute magnitude of 16.0.[3]
