(5496) 1973 NA
|Discovered by||E. F. Helin|
|Discovery site||Palomar Obs.|
|Discovery date||4 July 1973|
|MPC designation||(5496) 1973 NA|
|1973 NA · 1992 OA|
|Apollo · NEO|
|Orbital characteristics |
|Epoch 31 July 2016 (JD 2457600.5)|
|Uncertainty parameter 0|
|Observation arc||41.30 yr (15,086 days)|
|3.80 yr (1,388 days)|
|0° 15m 33.84s / day|
|Earth MOID||0.0902 AU|
|Dimensions||1.88 km (calculated)|
|C/X  · S |
(5496) 1973 NA, is a very eccentric and heavily tilted asteroid, classified as near-Earth object of the Apollo group, approximately 2 kilometers in diameter. It was discovered on 4 July 1973, by American astronomer Eleanor Helin at the U.S. Palomar Observatory in California. At the time of its discovery, it was the most highly inclined minor planet known to exist.
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 a high eccentricity of 0.64 and an exceptionally high inclination of 68° with respect to the ecliptic. No precoveries were taken. The asteroid's observation arc even begins 2 days after its discovery.
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. 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 the Siding Spring Observatory in Australia. Its minimum orbit intersection distance with Earth is now 0.0902 AU (13,500,000 km).
The stony S-type asteroid is also classified as a transitional C/X-type according to observations by the NASA IRTF telescope. A rotational light-curve for this asteroid was obtained by American astronomer Brian Skiff from photometric observations made in June 2011. The light-curve gave a rotation period of ±0.001 hours with a brightness variation of 0.15 in 2.855magnitude (U=3).[a] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.88 kilometers, based on an absolute magnitude of 16.0.
- Skiff (2011) web: rotation period ±0.001 hours with a brightness amplitude of 2.855 mag. Observation rated Quality Code (U) of 3. Summary figures at 0.15Collaborative Asteroid Lightcurve Link (CALL) for (5496) 1973 NA
- "JPL Small-Body Database Browser: 5496 (1973 NA)" (2014-10-25 last obs.). Jet Propulsion Laboratory. Retrieved 1 March 2016.
- "LCDB Data for (5496)". Asteroid Lightcurve Database (LCDB). Retrieved 24 May 2016.
- Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbó, Marco; Hora, Joseph L.; Mueller, Michael (January 2014). "Physical characterization of Warm Spitzer-observed near-Earth objects". Icarus. 228: 217–246. arXiv:. Bibcode:2014Icar..228..217T. doi:10.1016/j.icarus.2013.10.004. Retrieved 24 May 2016.
- "5496 (1973 NA)". Minor Planet Center. Retrieved 1 March 2016.
- "JPL Small-Body Database Browser: 5496 (1973 NA) – Close-Approach Data". Jet Propulsion Laboratory. Retrieved 1 March 2016.
- Williams, Iwan P.; Collander-Brown, S. J. (February 1998). "The parent of the Quadrantid meteoroid stream". Monthly Notices of the Royal Astronomical Society. 294: 127. Bibcode:1998MNRAS.294..127W. doi:10.1046/j.1365-8711.1998.01168.x. Retrieved 1 March 2016.
- Asteroid Lightcurve Database (LCDB), query form (info)
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (5001)-(10000) – Minor Planet Center
- (5496) 1973 NA at the JPL Small-Body Database