(26308) 1998 SM165

Trans-Neptunian binary October 2019 yes #C2E0FF 1998SM165-Trujillo-HST.jpg Hubble Space Telescope image of 1998 SM 165 and its companion, taken in December 2001 (26308) 1998 SM 165 N. Danzl Kitt Peak Obs. 16 September 1998 (26308) 1998 SM 165 TNOtwotinoKozaidistant 4 September 2017 (JD 2458000.5) 2 32.26 yr (11,784 days) 12 October 1982 64.968 AU 29.866 AU 47.417 AU 0.3701 326.52 yr (119,261 days) 47.484° 0.0030 ms / day 13.521° 183.21° 130.22° 1(96 12 km in diameter) 268 28 km (derived)287 36 km 6.87 0.018 18 kg 0.51 +0.29 -0.14 g/cm3 8.40 0.05 h 0.07 0.02 5.7 (26308) 1998 SM 165 is a resonant trans-Neptunian object and binary system from the Kuiper belt in the outermost regions of the Solar System. It was discovered on 16 September 1998, by American astronomer Nichole Danzl at the Kitt Peak National Observatory in Arizona. It is classified as a twotino and measures approximately 280 kilometers in diameter. Its minor-planet moon was discovered in 2001. Twotino thumb|left|The orbit of 1998 SM 165 compared to Pluto and Neptune 1998 SM 165 has a semi-major axis (average distance from the Sun) near the edge of the classical belt. The Deep Ecliptic Survey (DES) list this trans-Neptunian object as a twotino that stays in a 1:2 orbital resonance with the planet Neptune (for every one orbit that a twotino makes, Neptune orbits twice). Physical characteristics The observations with the infrared Spitzer Space Telescope combined with the orbits established using the Hubble Space Telescope allow the estimation of the density, assuming the components have an equal albedo. The resulting estimate of 0.51 +0.29 -0.14 g/cm3 is similar to the density of the binary plutino 47171 Lempo (0.3–0.8 g/cm3) and Saturn's moon Hyperion (0.567 0.102 g/cm3) Such a low density is indicative of a highly porous composition dominated by ice. 1998 SM 165 is fairly red, with a color comparable to 79360 Sila–Nunam. Satellite On 22 December 2001, a minor-planet moon was discovered by American astronomers Michael Brown and Chad Trujillo using the Hubble Space Telescope. The discovery was announced in January 2002. The satellite measures approximately 96 +/- 12 km on in diameter and orbits its primary at a distance of 11,310 +/- 110 km on. Assuming a circular orbit, this takes 130.1 1 days to complete one orbit. Numbering and naming This minor planet was numbered by the Minor Planet Center on 5 July 2001. As of 2025, it has not been named. References 30em 2015-01-16 last obs. JPL Small-Body Database Browser: 26308 (1998 SM165) https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2026308 Jet Propulsion Laboratory 11 October 2017 26308 (1998 SM165) Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=26308 11 October 2017 MPC/MPO/MPS Archive Minor Planet Center https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html 24 February 2018 MPEC 2009-J35 :Distant Minor Planets (2009 MAY 29.0 TT) 2009-05-08 Minor Planet Center https://www.minorplanetcenter.net/iau/mpec/K09/K09J35.html 22 August 2016 Marc W. Buie Marc W. Buie 2007/09/11 using 73 observations Orbit Fit and Astrometric record for 26308 SwRI (Space Science Department) http://www.boulder.swri.edu/~buie/kbo/astrom/26308.html 2009-05-12 (26308) 1998 SM165 and S/2001 (26308) 1 johnstonsarchive 21 September 2014 http://www.johnstonsarchive.net/astro/astmoons/am-26308.html 11 October 2017 J. Spencer J. Stansberry W. Grundy K. Noll September 2006 Bulletin of the American Astronomical Society 38 546 A Low Density for Binary Kuiper Belt Object (26308) 1998 SM165 American Astronomical Society 2006DPS....38.3401S J. Stansberry W. Grundy J-L. Margot D. Cruikshank J. Emery G. Rieke D. Trilling The Albedo, Size, and Density of Binary Kuiper Belt Object (47171) 1999 TC36 The Astrophysical Journal 643 May 2006 1 556–566 astro-ph/0602316 2006ApJ...643..556S 10.1086/502674 18146599 Jacobson R. A. Antreasian P. G. Bordi J. J. Criddle K. E. R. Ionasescu J. B. Jones R. A. Mackenzie M. C. Meek D. Parcher F. J. Pelletier W. M. Jr. Owen D. C. Roth I. M. Roundhill J. R. Stauch The Gravity Field of the Saturnian System from Satellite Observations and Spacecraft Tracking Data The Astronomical Journal 132 2520–2526 10.1086/508812 2006AJ....132.2520J December 2006 6 free External links List Of Transneptunian Objects, Minor Planet Center 26308 26308 (26308) 1998 SM 165 026308 Category:Discoveries by Nichole M. Danzl 026308 19980916 026308