(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]

    (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.

    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. 1 2 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. 1 2 3 4 5 "JPL Small-Body Database Browser: 5496 (1973 NA)" (2014-10-25 last obs.). Jet Propulsion Laboratory. Retrieved 26 May 2017.
    2. 1 2 3 4 "5496 (1973 NA)". Minor Planet Center. Retrieved 1 March 2016.
    3. 1 2 3 4 5 "LCDB Data for (5496)". Asteroid Lightcurve Database (LCDB). Retrieved 24 May 2016.
    4. 1 2 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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