1720 Niels

Main-belt asteroid October 2019 yes 1720 Niels #D6D6D6 7 February 1935 K. Reinmuth Heidelberg Obs. (1720) Niels 1935 CQ1940 WH1951 AL1953 VO 11959 RA1963 WE Niels (discoverer's grandson) main-belt(inner) 4 September 2017 (JD 2458000.5) 0 89.52 yr (32,697 days) 2.4170 AU 1.9593 AU 2.1881 AU 0.1046 3.24 yr (1,182 days) 240.21° 0.7301° 127.86° 308.86° 6.394 0.0916.566 0.063 km8.18 km (calculated) 9.976 h19.2 h 0.20 (assumed)0.2154 0.02840.227 0.017 LSS 12.22 0.2512.813.2 1720 Niels, provisional designation 1935 CQ, is a stony asteroid from the inner regions of the asteroid belt, approximately 6.4 kilometers in diameter. It was discovered on 7 February 1935, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany, and named after a grandson of the discoverer. Orbit and classification Niels orbits the Sun in the inner main-belt at a distance of 2.0–2.4 AU once every 3 years and 3 months (1,182 days). Its orbit has an eccentricity of 0.10 and an inclination of 1° with respect to the ecliptic. First observed at Heidelberg in 1927, Niels observation arc begins with its official discovery observation in 1935. Physical characteristics Pan-STARRS classifies this stony asteroid as a LS-type, an intermediate to the rare L-type asteroids. Rotation period A rotational lightcurve of Niels was obtained by astronomer Maurice Clark in December 2005. It gave it a rotation period of 9.976 hours with a brightness variation of 0.15 magnitude (U=1). In November 2008, photometric observations by amateur astronomer Pierre Antonini gave another period of 19.2 hours with an amplitude of 0.01 (U=1-). As of 2017, a secure period for Niels has not yet been obtained. Diameter and albedo According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Niels measures 6.394 kilometers in diameter, and its surface has an albedo of 0.227, superseding a preliminary result that gave a slightly larger diameter and lower albedo. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.18 kilometers based on an absolute magnitude of 12.8. Naming The minor planet was named by the discoverer after his grandson, Niels. Reinmuth also named 1719 Jens after one of his grandsons. The official 1720 naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3933). References 30em 2017-05-05 last obs. JPL Small-Body Database Browser: 1720 Niels (1935 CQ) https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001720 Jet Propulsion Laboratory 7 June 2017 Dictionary of Minor Planet Names – (1720) Niels Schmadel Lutz D. Springer Berlin Heidelberg 136–137 2007 978-3-540-00238-3 10.1007/978-3-540-29925-7_1721 (1720) Niels 1720 Niels (1935 CQ) Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=1720 22 December 2016 Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008) Appendix – Publication Dates of the MPCs Schmadel Lutz D. Springer Berlin Heidelberg 221 978-3-642-01964-7 10.1007/978-3-642-01965-4 Asteroids and comets rotation curves – (1720) Niels Behrend Raoul Geneva Observatory http://obswww.unige.ch/~behrend/page4cou.html#001720 22 December 2016 1 April 2019 https://web.archive.org/web/20190401181659/http://obswww.unige.ch/~behrend/page4cou.html#001720 dead 1720 22 December 2016 6 A. Mainzer T. Grav J. Masiero E. Hand J. Bauer D. Tholen R. S. McMillan T. Spahr R. M. Cutri E. Wright J. Watkins W. Mo C. Maleszewski November 2011 NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results The Astrophysical Journal 741 2 25 2011ApJ...741...90M 10.1088/0004-637X/741/2/90 1109.6407 Clark, Maurice March 2007 Lightcurve Results for 1318 Nerina, 222 Lermontov 3015 Candy, 3089 Oujianquan, 3155 Lee, 6410 Fujiwara, 6500 Kodaira, (8290) 1992 NP, 9566 Rykhlova, (42923) 1999 SR18, and 2001 FY http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2007MPBu...34...19C The Minor Planet Bulletin 34 1 19–22 1052-8091 2007MPBu...34...19C 22 December 2016 6 Peter Veres Robert Jedicke Alan Fitzsimmons Larry Denneau Mikael Granvik Bryce Bolin Serge Chastel Richard J. Wainscoat William S. Burgett Kenneth C. Chambers Heather Flewelling Nick Kaiser Eugen A. Magnier Jeff S. Morgan Paul A. Price John L. Tonry Christopher Waters November 2015 Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V Icarus 261 34–47 2015Icar..261...34V 10.1016/j.icarus.2015.08.007 1506.00762 22 December 2016 6 Joseph R. Masiero T. Grav A. K. Mainzer C. R. Nugent J. M. Bauer R. Stevenson S. Sonnett August 2014 Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014ApJ...791..121M The Astrophysical Journal 791 2 11 2014ApJ...791..121M 10.1088/0004-637X/791/2/121 1406.6645 22 December 2016 External links Asteroid Lightcurve Database (LCDB), query form (info https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html 16 December 2017 ) Dictionary of Minor Planet Names, Google books Asteroids and comets rotation curves, CdR https://web.archive.org/web/20241208174218/http://obswww.unige.ch/~behrend/page_cou.html 8 December 2024 – Observatoire de Genève, Raoul Behrend Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center 1720 1719 Jens 1720 1721 Wells 001720 Category:Discoveries by Karl Wilhelm Reinmuth Category:Named minor planets 19350207