| 词条 | 2018 RY7 |
| 释义 |
| minorplanet = yes | name = {{mp|2018 RY|7}} | background = #FFC2E0 | image = | image_size = | caption = | discovery_ref = [1] | discoverer = MLS M. B. Africano [2] | discovery_site = Mount Lemmon Obs. | discovered = 14 September 2018 {{small|(first observed only)}} | mpc_name = {{mp|2018 RY|7}} | alt_names = | pronounced = | named_after = | mp_category = NEO{{·}}Apollo [1] Earth crosser | orbit_ref = | epoch = 27 April 2019 (JD 2458600.5) | uncertainty = 4 | observation_arc = 89 days | aphelion = 1.1656 AU | perihelion = 0.8668 AU | semimajor = 1.0162 AU | eccentricity = 0.1470 | period = 1.02 yr (374 d) | mean_anomaly = 80.480° | mean_motion = {{Deg2DMS|0.9622|sup=ms}} / day | inclination = 13.351° | asc_node = 2.8171° | arg_peri = 136.88° | moid = 0.0938 AU (36.5424 LD) | mean_diameter = {{val|23|-|103|ul=m}} {{small|(est.)}}[6][7]{{ref label|A|a|none}} | mass = | density = | rotation = | albedo = | spectral_type = | abs_magnitude = 24.4 }}{{mp|2018 RY|7}}, is a small near-Earth object of the Apollo group. It is currently trapped in a 3:5 mean motion resonance with Venus.[9] The object was first observed on 14 September 2018, by astronomer B. M. Africano with the Mount Lemmon Survey at Mount Lemmon Observatory, Arizona, United States.[2][1] Orbit and physical propertiesThe asteroid's orbit determination is in need of some improvement. It orbits the Sun at a distance of 0.87–1.17 AU once every 374 days (semi-major axis of 1.016 AU). Its orbit has an eccentricity of 0.1470 and an inclination of 13.35° with respect to the ecliptic. It is a member of Apollo dynamical class in both the JPL Small-Body Database and the Minor Planet Center.[1] Apollo asteroids are Earth-crossing asteroids. False binary{{mp|2018 RY|7}} is currently trapped in a 3:5 mean motion resonance with Venus and follows an orbit very similar to that of {{mpl|2017 SN|16}}.[9] This pair of Near-Earth objects show the highest observed level of dynamical coherence among the population of near-Earth objects.Physical characteristics{{mp|2018 RY|7}} has an absolute magnitude of 24.4 which gives a calculated mean diameter between 23 and 103 meters for an assumed geometric albedo of 0.60 and 0.03, respectively.[6][7]Notes{{refbegin}}
References1. ^1 2 3 4 {{cite web |title = 2018 RY7 |work = Minor Planet Center |url = http://www.minorplanetcenter.net/db_search/show_object?object_id=2018+RY7 |accessdate = 13 November 2018}} [1][2][3][4][5]2. ^1 2 {{cite web |title = MPEC 2018-S12 : 2018 RY7 |date = 16 September 2018 |publisher = Minor Planet Electronic Circular |url = https://www.minorplanetcenter.net/mpec/K18/K18S12.html |accessdate = 7 January 2019}} 3. ^1 2 {{cite web |title = Asteroid Size Estimator |publisher = CNEOS NASA/JPL |url = https://cneos.jpl.nasa.gov/tools/ast_size_est.html |accessdate = 13 November 2018}} 4. ^1 2 {{cite web |title = 2018 RY7 – Summary |work = NEODyS-2, Near Earth Objects – Dynamic Site |url = http://newton.dm.unipi.it/neodys2/index.php?pc=1.1.0&n=2018+RY7 |accessdate = 13 November 2018}} 5. ^1 2 {{Cite journal |first1 = Carlos |last1 = de la Fuente Marcos |first2 = Raúl |last2 = de la Fuente Marcos |date = 11 February 2019 |title = Dancing with Venus in the shadow of the Earth: a pair of genetically related near-Earth asteroids trapped in a mean-motion resonance |url = https://academic.oup.com/mnrasl/article-abstract/483/1/L37/5184474 |journal = Letters |volume = 483 |issue = 1 |pages = L37-L41 |bibcode = 2019MNRAS.483L..37D |doi = 10.1093/mnrasl/sly214 |arxiv = 1811.04873 |access-date= 4 December 2018}} }} External links
4 : Apollo asteroids|Minor planet object articles (unnumbered)|Earth-crosser asteroids|Astronomical objects discovered in 2018 |
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