The trans-Neptunian object (119951) 2002 KX14 revealed via multiple stellar occultations

¹ Instituto de Astrofísica de Andalucía – Consejo Superior de Investigaciones Científicas (IAA-CSIC), Glorieta de la Astronomía S/N, 18008 Granada, Spain
² Florida Space Institute, 12354 Research Parkway, Partnership I, Room 211, 32826 Orlando, USA
³ Federal University of Technology - Paraná (UTFPR/PPGFA), Av. Sete de Setembro, 3165, CEP 80230-901 - Curitiba - PR - Brazil
⁴ Laboratório Interinstitucional de e-Astronomia (LIneA/INCT do e-Universo), Av. Pastor Martin Luther King Jr, 126, 20765 Rio de Janerio, Brazil
⁵ LTE, Observatoire de Paris, Université PSL, Sorbonne Université, Université de Lille, LNE,CNRS 61 Avenue de l’Observatoire, 75014 Paris, France
⁶ Institut Polytechnique des Sciences Avancées IPSA, 63 boulevard de Brandebourg, 94200 Ivry-sur-Seine, France
⁷ LIRA, CNRS UMR-8254, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, Meudon 92190, France
⁸ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, USA
⁹ Astronomical Observatory Institute, Faculty of Physics and Astronomy, Adam Mickiewicz University, Słoneczna 36, 60-286 Poznań, Poland
¹⁰ Astronomical Observatory of Odesa I.I. Mechnikov National University, 1v Marazliivska str., Odesa 65014, Ukraine
¹¹ Konkoly Observatory, Budapest, Hungary
¹² ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, Szent Imre h u 112, Szombathely, Hungary
¹³ Maastricht University, Maastricht Science Programme, Maastricht, The Netherlands
¹⁴ Observatoire de Nandrin, Société Astronomique de Liège, Belgium
¹⁵ Institute of Planetary Research, DLR, Rutherfordstr. 2, 12489 Berlin, Germany
¹⁶ Centro de Estudios de Física del Cosmos de Aragón, Plaza de San Juan, 1, 44001 Teruel, Spain
¹⁷ La Hita Observatory, Toledo, Spain
¹⁸ International Occultation Timing Association (IOTA), USA
¹⁹ Department of Astronomy, University of Virginia, Charlottesville, VA, USA
²⁰ New Mexico State University - Apache Point Observatory, USA
²¹ GOA, UFES, Av. Fernando FErrari, 514 Vitória, ES, Brazil
²² Sonear3 Observatory, USA
²³ DogsHeaven Observatory, Brasília, Brazil
²⁴ Botorrita Observatory, Botorrita, Spain
²⁵ Universidade Federal do Rio de Janeiro - Observatório do Valongo, Ladeira Pedro Antônio 43, CEP 20.080-090 Rio de Janeiro, Brazil
²⁶ Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro RJ-20921-400, Brazil
²⁷ Space Science and Solar Energy Research and Application Center (UZAYMER), University of Çukurova, Adana 01330, Türkiye
²⁸ Mesopotamia Astronomy Association, Batman 72040, Türkiye
²⁹ Yuregir Science Center Adana 01260, Türkiye
³⁰ National Observatories of Türkiye, TUG, 07058 Antalya, Türkiye
³¹ TÜBİTAK, Tunus Cad., No:80, 06680 Kavaklıdere, Ankara, Türkiye
³² Department of Space Sciences and Technologies, Akdeniz University, Campus, Antalya 07058, Türkiye
³³ Buelach Observatory, Bülach, Switzerland
³⁴ IOTA/ES, International Occultation Timing Association/European Section e.V., Am Brombeerhag 13, 30459 Hannover, Germany
³⁵ Czech Astronomical Society, Fričova 298, 251 65 Ondřejov, Czech Republic
³⁶ Observatory in Rokycany and Pilsen, p.o., Voldušská 721, 337 01 Rokycany, Czech Republic
³⁷ naXys, Department of Mathematics, University of Namur, Rue de Bruxelles 61, Namur 5000, Belgium
³⁸ Institute of Physics, Federal University of Uberlândia, Av. João Naves de Ávila, Uberlândia, Minas Gerais CEP 38408-100, Brazil

^★ Corresponding author: juanluisrizos@gmail.com

Received: 17 February 2025
Accepted: 24 March 2025

Abstract

Context. Trans-Neptunian objects (TNOs) are icy bodies located in the outer solar system that offer key insights into the primordial conditions of our planetary system. The stellar occultation technique has proven to be an essential tool for studying these distant and faint objects, enabling precise determinations of their size, shape, and albedo, while also improving estimates of their orbital parameters. Among them, (119951) 2002 KX14 is a large classical TNO with limited previous observations and unresolved questions regarding its physical properties.

Aims. This study aims to analyze and characterize the TNO (119951) 2002 KX14 through observations of stellar occultations, providing unique measurements of its size, shape, and albedo. Shape measurements are especially relevant, as only thirteen TNOs have had their projected shapes measured. These results contribute to our understanding of the physical properties of this object and the broader TNO population.

Methods. Five stellar occultations by 2002 KX14 were observed from 2020 to 2023, involving multiple telescopes across different locations in Europe and the Americas. High-precision astrometry and photometric data were used to predict the occultation paths and extract ingress and egress timings. One of the events was detected from six sites and there are also several close misses, providing precise constraints for an accurate determination of the object’s limb. Furthermore, elliptical fits to the occultations chords allowed for the determination of the object’s shape and area-equivalent diameter. The geometric albedo was calculated by combining the occultation results with published absolute magnitudes.

Results. The five occultations resulted in 15 positive chords that allowed us to accurately measure the shape and size of 2002 KX14. Given that the rotational variability of this body is minimal, we can reasonably assume that the variations are due to albedo features, since the body is classed as a Maclaurin spheroid. The projected ellipse has semi-major and semi-minor axes of 241.0 ± 7.2 km and 157.1 ± 5.2 km, respectively, corresponding to an average area-equivalent diameter of 389.2 ± 8.7 km. The geometric albedo was estimated to be 11.9 ± 0.7%. These values differ from the 455 ± 27 km diameter and the 9.7_-1.3^+1.4% albedo derived from thermal measurements, offering a more refined understanding of the object’s physical properties.