Results from the 2014 november 15th. multi-chord stellar occultation by the TNO (229762) 2007 UK126

Benedetti-Rossi, G. et. al.We present results derived from the first multi-chord stellar occultation by the trans-Neptunian object (229762) 2007 UK, observed on 2014 November 15. The event was observed by the Research and Education Collaborative Occultation Network project and International Occultation Timing Association collaborators throughout the United States. Use of two different data analysis methods obtain a satisfactory fit to seven chords, yielding an elliptical fit to the chords with an equatorial radius of R = 338 km and equivalent radius of R = 319 km. A circular fit also gives a radius of R = 324 km. Assuming that the object is a Maclaurin spheroid with indeterminate aspect angle, and using two published absolute magnitudes for the body, we derive possible ranges for geometric albedo between p = 0.159 and p = 0.189 , and for the body oblateness between ∈ = 0.105 and ∈ = 0.118 . For a nominal rotational period of 11.05 hr, an upper limit for density of ρ = 1740 kg m is estimated for the body.The RECON project would not be possible without all of the support from our community teams (teachers, students, and community members) and was funded by NSF grants AST-1212159, AST-1413287, and AST-1413072. Special thanks to Dean and Starizona for their support of RECON above and beyond the usual bounds of a commercial relationship. Part of the research leading to these results has received funding from the European Research Council under the European Community's H2020 (2014-2020/ERC Grant Agreement n 669416 >LUCKY STAR>). Funding from Spanish grant AYA-2014-56637-C2-1-P is acknowledged, as is the Proyecto de Excelencia de la Junta de Andaluca, J. A. 2012-FQM1776. R.D. acknowledges the support of MINECO for his Ramon y Cajal Contract. FEDER funds are also acknowledged. A.D.O. is thankful for the support of the CAPES (BEX 9110/12-7) FAPERJ/PAPDRJ (E-26/200.464/2015) grants. G.B.R. is thankful for the support of CAPES/Brazil and FAPERJ (Grant E-01/2015/209545). J.I.B.C. acknowledges CNPq for a PQ2 fellowship (process number 308489/2013-6). L.G. thanks the support from CONACYT through grant 167236. M.A. thanks the CNPq (Grants 473002/2013-2 and 308721/2011-0) and FAPERJ (Grant E-26/111.488/2013). P.S.-S. acknowledges that part of the research leading to these results has received funding from the European Unions Horizon 2020 Research and Innovation Programme, under Grant Agreement no 687378. R.V.M. acknowledges the following grants: CNPq-306885/2013, CAPES/Cofecub-2506/2015, FAPERJ/PAPDRJ-45/2013, FAPERJ/CNE/05-2015.Peer Reviewe