(5646) 1990 TR
Probable rare-type binary asteroid
title: "(5646) 1990 TR" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["amor-asteroids", "discoveries-by-hiroshi-kaneda", "discoveries-by-seiji-ueda", "binary-asteroids", "unclassifiable-asteroids-(smass)", "astronomical-objects-discovered-in-1990"] description: "Probable rare-type binary asteroid" topic_path: "general/amor-asteroids" source: "https://en.wikipedia.org/wiki/(5646)_1990_TR" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Probable rare-type binary asteroid ::
::data[format=table title="Infobox planet"]
| Field | Value |
|---|---|
| minorplanet | yes |
| name | (5646) 1990 TR |
| background | #FFC2E0 |
| discovery_ref | |
| discovered | 11 October 1990 |
| discoverer | S. Ueda |
| H. Kaneda | |
| discovery_site | Kushiro Obs. |
| mpc_name | (5646) 1990 TR |
| alt_names | 1990 TR |
| mp_category | AmorNEO |
| orbit_ref | |
| epoch | 4 September 2017 (JD 2458000.5) |
| uncertainty | 0 |
| observation_arc | 26.90 yr (9,825 days) |
| aphelion | 3.0791 AU |
| perihelion | 1.2087 AU |
| semimajor | 2.1439 AU |
| eccentricity | 0.4362 |
| period | 3.14 yr (1,147 days) |
| mean_anomaly | 218.56° |
| mean_motion | / day |
| inclination | 7.9118° |
| asc_node | 14.141° |
| arg_peri | 335.68° |
| moid | 0.2112 AU 82.3 LD |
| satellites | 1 |
| dimensions | km |
| 2.30 km (derived) | |
| km | |
| km | |
| 4.3 km (dated) | |
| rotation | h |
| h | |
| h | |
| albedo | 0.18 (assumed) |
| | spectral_type | SMASS = U QSU | | abs_magnitude | 14.315.0015.415.4515.67 | ::
| minorplanet = yes | name = (5646) 1990 TR | background = #FFC2E0 | image = | image_size = | caption = | discovery_ref = | discovered = 11 October 1990 | discoverer = S. Ueda H. Kaneda | discovery_site = Kushiro Obs. | mpc_name = (5646) 1990 TR | alt_names = 1990 TR | pronounced = | named_after = | mp_category = AmorNEO | orbit_ref = | epoch = 4 September 2017 (JD 2458000.5) | uncertainty = 0 | observation_arc = 26.90 yr (9,825 days) | aphelion = 3.0791 AU | perihelion = 1.2087 AU | semimajor = 2.1439 AU | eccentricity = 0.4362 | period = 3.14 yr (1,147 days) | mean_anomaly = 218.56° | mean_motion = / day | inclination = 7.9118° | asc_node = 14.141° | arg_peri = 335.68° | moid = 0.2112 AU 82.3 LD | satellites = 1 | dimensions = km 2.30 km (derived) km km 4.3 km (dated) | rotation = h h h | albedo = 0.18 (assumed)
| spectral_type = SMASS = U QSU | abs_magnitude = 14.315.0015.415.4515.67
**** is a probable rare-type binary asteroid classified as near-Earth object of the Amor group, approximately 2.3 kilometers in diameter. It was discovered on 11 October 1990, by Japanese astronomers Seiji Ueda and Hiroshi Kaneda at Kushiro Observatory near Kushiro, in eastern Hokkaido, Japan.
Orbit
The asteroid orbits the Sun at a distance of 1.2–3.1 AU once every 3 years and 2 months (1,147 days). Its orbit has an eccentricity of 0.44 and an inclination of 8° with respect to the ecliptic. The body's observation arc begins with its first observation at the Siding Spring Observatory, five months prior to its official discovery observation at Kushiro.
Lightcurve
In December 2012, the so far best rated rotational lightcurve was obtained by American astronomer Brian Warner at his Palmer Divide Observatory in Colorado. Lightcurve analysis gave a rotation period of 3.1999 hours with a brightness variation of 0.12 magnitude (). Photometric observations also gave a period of 19.47 hours for a probable asteroid moon, with a measured diameter-ratio of , which translates into a diameter of 400 meters for its moon.
Diameter and albedo
According to the surveys carried out by the Spitzer Space Telescope and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid measures 2.03 and 2.723 kilometers in diameter and its surface has an albedo of 0.19 and 0.66. The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.18 and derives a diameter of 2.3 kilometers based on an absolute magnitude of 15.67.
References
|type = 2017-03-27 last obs. |title = JPL Small-Body Database Browser: 5646 (1990 TR) |url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2005646 |publisher = Jet Propulsion Laboratory |accessdate = 26 May 2017}}
|title = 5646 (1990 TR) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=5646 |accessdate = 12 February 2017}}
|date = 2013-11-18 |title = Binary and Ternary near-Earth Asteroids detected by radar |publisher = NASA/JPL Asteroid Radar Research |author = Dr. Lance A. M. Benner |url = http://echo.jpl.nasa.gov/~lance/binary.neas.html |archive-url = https://web.archive.org/web/20040608071121/http://echo.jpl.nasa.gov/~lance/binary.neas.html |url-status = dead |archive-date = 2004-06-08 |accessdate = 2014-03-01}}
|display-authors = 6 |first1 = A. |last1 = Mainzer |first2 = T. |last2 = Grav |first3 = J. |last3 = Bauer |first4 = J. |last4 = Masiero |first5 = R. S. |last5 = McMillan |first6 = R. M. |last6 = Cutri |first7 = R. |last7 = Walker |first8 = E. |last8 = Wright |first9 = P. |last9 = Eisenhardt |first10 = D. J. |last10 = Tholen |first11 = T. |last11 = Spahr |first12 = R. |last12 = Jedicke |first13 = L. |last13 = Denneau |first14 = E. |last14 = DeBaun |first15 = D. |last15 = Elsbury |first16 = T. |last16 = Gautier |first17 = S. |last17 = Gomillion |first18 = E. |last18 = Hand |first19 = W. |last19 = Mo |first20 = J. |last20 = Watkins |first21 = A. |last21 = Wilkins |first22 = G. L. |last22 = Bryngelson |first23 = A. |last23 = Del Pino Molina |first24 = S. |last24 = Desai |first25 = M. |last25 = Gómez Camus |first26 = S. L. |last26 = Hidalgo |first27 = I. |last27 = Konstantopoulos |first28 = J. A. |last28 = Larsen |first29 = C. |last29 = Maleszewski |first30 = M. A. |last30 = Malkan |first31 = J.-C. |last31 = Mauduit |first32 = B. L. |last32 = Mullan |first33 = E. W. |last33 = Olszewski |first34 = J. |last34 = Pforr |first35 = A. |last35 = Saro |first36 = J. V. |last36 = Scotti |first37 = L. H. |last37 = Wasserman |date = December 2011 |title = NEOWISE Observations of Near-Earth Objects: Preliminary Results |journal = The Astrophysical Journal |volume = 743 |issue = 2 |page = 17 |bibcode = 2011ApJ...743..156M |doi = 10.1088/0004-637X/743/2/156 |arxiv = 1109.6400|s2cid = 239991 }}
|title = LCDB Data for (5646) |publisher = Asteroid Lightcurve Database (LCDB) |url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=5646%7C |accessdate = 12 February 2017}}
|display-authors = 6 |first1 = Michael |last1 = Mueller |first2 = M. |last2 = Delbo' |first3 = J. L. |last3 = Hora |first4 = D. E. |last4 = Trilling |first5 = B. |last5 = Bhattacharya |first6 = W. F. |last6 = Bottke |first7 = S. |last7 = Chesley |first8 = J. P. |last8 = Emery |first9 = G. |last9 = Fazio |first10 = A. W. |last10 = Harris |first11 = A. |last11 = Mainzer |first12 = M. |last12 = Mommert |first13 = B. |last13 = Penprase |first14 = H. A. |last14 = Smith |first15 = T. B. |last15 = Spahr |first16 = J. A. |last16 = Stansberry |first17 = C. A. |last17 = Thomas |date = April 2011 |title = ExploreNEOs. III. Physical Characterization of 65 Potential Spacecraft Target Asteroids |journal = The Astronomical Journal |volume = 141 |issue = 4 |page = 9 |bibcode = 2011AJ....141..109M |doi = 10.1088/0004-6256/141/4/109|s2cid = 44827674 |url = https://authors.library.caltech.edu/23152/1/Mueller2011p13239Astron_J.pdf }}
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|author = Wisniewski, Wieslaw Z. |date = December 1992 |title = The unusual lightcurve of 1990 TR |journal = In Lunar and Planetary Inst. |pages = 653 |bibcode = 1992acm..proc..653W}}
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|author = Warner, Brian D. |date = April 2016 |title = Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 October-December |journal = The Minor Planet Bulletin |volume = 43 |issue = 2 |pages = 143–154 |pmid = 32455373 |pmc = 7243997 |issn = 1052-8091 |bibcode = 2016MPBu...43..143W}}
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