| 词条 | (5496) 1973 NA |
| 释义 |
| minorplanet = yes | name = (5496) 1973 NA | background = #FFC2E0 | image = | image_size = | caption = | discovery_ref = | discovered = 4 July 1973 | discoverer = E. F. Helin | discovery_site = Palomar Obs. | mpc_name = (5496) 1973 NA | alt_names = 1973 NA{{·}}1992 OA | named_after = | mp_category = Apollo{{·}}NEO [2] | orbit_ref = | epoch = 4 September 2017 (JD 2458000.5) | uncertainty = 0 | observation_arc = 41.30 yr (15,086 days) | aphelion = 3.9837 AU | perihelion = 0.8865 AU | semimajor = 2.4351 AU | eccentricity = 0.6360 | period = 3.80 yr (1,388 days) | mean_anomaly = 240.93° | mean_motion = {{Deg2DMS|0.2594|sup=ms}} / day | inclination = 68.006° | asc_node = 101.04° | arg_peri = 118.02° | moid = 0.0904 AU | dimensions = 1.88 km {{small|(calculated)}}[4] | rotation = {{val|2.855|0.001}} h{{efn|name=lcdb-Skiff-2011}} | albedo = 0.20 {{small|(assumed)}}[4] | spectral_type = C/X [6]{{·}}S [4] | abs_magnitude = 16.0[4] }} (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{{mp|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 {{mp|Comet 1491 I}} and comet 96P/Machholz,[11] as well as {{mpl|(196256) 2003 EH|1}}.[12][13]Orbit and classificationThe 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. 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 {{convert|0.07984|AU|km|abbr=on|lk=off|sigfig=3}} from Earth on one of its closest approaches ever computed.[16] 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 {{convert|0.0904|AU|km|abbr=on|sigfig=3}}. Physical characteristicsThe stony S-type asteroid is also classified as a transitional C/X-type according to observations by the NASA IRTF telescope.[6] 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 {{val|2.855|0.001}} hours with a brightness variation of 0.15 magnitude ({{small|U=3}}).{{efn|name=lcdb-Skiff-2011}} 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.[4] Notes{{notelist|refs={{efn|name=lcdb-Skiff-2011|1=Skiff (2011) web: rotation period {{val|2.855|0.001}} hours with a brightness amplitude of {{val|0.15}} mag. Observation rated Quality Code (U) of 3. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (5496) 1973 NA}}}} References1. ^1 {{cite web |title = JPL Small-Body Database Browser: 5496 (1973 NA) – Close-Approach Data |url = http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2005496;old=0;orb=0;cov=0;log=0;cad=1#cad |publisher = Jet Propulsion Laboratory |accessdate = 1 March 2016}} [1][2][3][4][5][6][7]2. ^1 2 3 4 {{cite web |title = 5496 (1973 NA) |work = Minor Planet Center |url = http://www.minorplanetcenter.net/db_search/show_object?object_id=5496 |accessdate = 1 March 2016}} 3. ^1 2 3 4 5 {{cite web |title = LCDB Data for (5496) |publisher = Asteroid Lightcurve Database (LCDB) |url = http://www.minorplanet.info/PHP/GenerateALCDEFPage_Local.php?AstInfo=5496%7C |accessdate = 24 May 2016}} 4. ^1 {{cite journal |first1 = Iwan P. |last1 = Williams |first2 = S. J. |last2 = Collander-Brown |date = February 1998 |title = The parent of the Quadrantid meteoroid stream |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1998MNRAS.294..127W |journal = Monthly Notices of the Royal Astronomical Society |page = 127 |volume = 294 |bibcode = 1998MNRAS.294..127W |doi = 10.1046/j.1365-8711.1998.01168.x |access-date= 1 March 2016}} 5. ^1 2 {{cite journal |first1 = Cristina A. |last1 = Thomas |first2 = Joshua P. |last2 = Emery |first3 = David E. |last3 = Trilling |first4 = Marco |last4 = Delbó |first5 = Joseph L. |last5 = Hora |first6 = Michael |last6 = Mueller |date = January 2014 |title = Physical characterization of Warm Spitzer-observed near-Earth objects |url = https://arxiv.org/pdf/1310.2000.pdf |journal = Icarus |volume = 228 |pages = 217–246 |bibcode = 2014Icar..228..217T |doi = 10.1016/j.icarus.2013.10.004 |arxiv = 1310.2000 |access-date= 24 May 2016}} 6. ^1 {{Cite journal |author = Jenniskens, P. |date = May 2004 |title = 2003 EH1 Is the Quadrantid Shower Parent Comet |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2004AJ....127.3018J |journal = The Astronomical Journal |volume = 127 |issue = 5 |pages = 3018–3022 |bibcode = 2004AJ....127.3018J |doi = 10.1086/383213 |access-date= 26 May 2017}} 7. ^1 {{Cite journal |first1 = V. |last1 = Porubcan |first2 = L. |last2 = Kornos |date = February 2005 |title = The Quadrantid meteor stream and 2003 EH1 |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2005CoSka..35....5P |journal = Contributions of the Astronomical Observatory Skalnaté Pleso |pages = 5–16.(CoSkaHomepage) |bibcode = 2005CoSka..35....5P |access-date= 26 May 2017}} }} External links
3 : Apollo asteroids|Discoveries by Eleanor F. Helin|Astronomical objects discovered in 1973 |
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