(5496) 1973 NA

(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.[2] At the time of its discovery, it was the most highly inclined minor planet known to exist. It may be the parent body of the Quadrantids.

(5496) 1973 NA
Discovery[1]
Discovered byE. F. Helin
Discovery sitePalomar Obs.
Discovery date4 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 arc41.30 yr (15,086 days)
Aphelion3.9837 AU
Perihelion0.8865 AU
2.4351 AU
Eccentricity0.6360
3.80 yr (1,388 days)
240.93°
0° 15m 33.84s / day
Inclination68.006°
101.04°
118.02°
Earth MOID0.0904 AU
Physical characteristics
Mean diameter
1.88 km (calculated)[3]
2.855±0.001 h[lower-alpha 1]
0.20 (assumed)[3]
C/X[4] · S[3]
16.0[1][3]

    Parent of the Quadrantids

    1973 NA is a possible parent body of the Quadrantids, a major meteor 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 are Comet 1491 I and comet 96P/Machholz,[5] as well as (196256) 2003 EH1.[6][7]

    Orbit and classification

    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 an eccentricity of 0.64 and an inclination of 68° with respect to the ecliptic.[1] No precoveries were taken. The asteroid's observation 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 the Siding Spring Observatory in Australia.[2] Its minimum orbit intersection distance with Earth is now 0.0904 AU (13,500,000 km).[1]

    Physical characteristics

    The stony S-type asteroid is also classified as a transitional C/X-type according to observations by the NASA IRTF telescope.[4] A rotational lightcurve for this asteroid was obtained by American astronomer Brian Skiff from photometric observations made in June 2011. Lightcurve analysis gave a well-defined rotation period of 2.855±0.001 hours with a brightness variation of 0.15 magnitude (U=3).[lower-alpha 1] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.88 kilometers with an absolute magnitude of 16.0.[3]

    Notes
    1. Skiff (2011) web: rotation period 2.855±0.001 hours with a brightness amplitude of 0.15 mag. Observation rated Quality Code (U) of 3. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (5496) 1973 NA

    References
    1. "JPL Small-Body Database Browser: 5496 (1973 NA)" (2014-10-25 last obs.). Jet Propulsion Laboratory. Retrieved 26 May 2017.
    2. "5496 (1973 NA)". Minor Planet Center. Retrieved 1 March 2016.
    3. "LCDB Data for (5496)". Asteroid Lightcurve Database (LCDB). Retrieved 24 May 2016.
    4. 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:1310.2000. Bibcode:2014Icar..228..217T. doi:10.1016/j.icarus.2013.10.004.
    5. Williams, Iwan P.; Collander-Brown, S. J. (February 1998). "The parent of the Quadrantid meteoroid stream". Monthly Notices of the Royal Astronomical Society. 294 (1): 127. Bibcode:1998MNRAS.294..127W. doi:10.1046/j.1365-8711.1998.01168.x.
    6. Jenniskens, P. (May 2004). "2003 EH1 Is the Quadrantid Shower Parent Comet". The Astronomical Journal. 127 (5): 3018–3022. Bibcode:2004AJ....127.3018J. doi:10.1086/383213.
    7. Porubcan, V.; Kornos, L. (February 2005). "The Quadrantid meteor stream and 2003 EH1". Contributions of the Astronomical Observatory Skalnaté Pleso. 35 (1): 5–16.(CoSkaHomepage). Bibcode:2005CoSka..35....5P.
    8. "JPL Small-Body Database Browser: 5496 (1973 NA) – Close-Approach Data". Jet Propulsion Laboratory. Retrieved 1 March 2016.
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