@article {28377, title = {The large trans-Neptunian object 2002 TC302 from combined stellar occultation, photometry, and astrometry data}, volume = {639}, year = {2020}, month = {2020/07/1}, pages = {A134}, abstract = {Context. Deriving physical properties of trans-Neptunian objects is important for the understanding of our Solar System. This requires observational efforts and the development of techniques suitable for these studies.
Aims: Our aim is to characterize the large trans-Neptunian object (TNO) 2002 TC302.
Methods: Stellar occultations offer unique opportunities to determine key physical properties of TNOs. On 28 January 2018, 2002 TC302 occulted a mv ~ 15.3 star with designation 593-005847 in the UCAC4 stellar catalog, corresponding to Gaia source 130957813463146112. Twelve positive occultation chords were obtained from Italy, France, Slovenia, and Switzerland. Also, four negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a TNO other than Pluto in terms of the number of chords published thus far. From the 12 chords, an accurate elliptical fit to the instantaneous projection of the body can be obtained that is compatible with the near misses.
Results: The resulting ellipse has major and minor axes of 543 {\textpm} 18 km and 460 {\textpm} 11 km, respectively, with a position angle of 3 {\textpm} 1 degrees for the minor axis. This information, combined with rotational light curves obtained with the 1.5 m telescope at Sierra Nevada Observatory and the 1.23 m telescope at Calar Alto observatory, allows us to derive possible three-dimensional shapes and density estimations for the body based on hydrostatic equilibrium assumptions. The effective diameter in equivalent area is around 84 km smaller than the radiometrically derived diameter using thermal data from Herschel and Spitzer Space Telescopes. This might indicate the existence of an unresolved satellite of up to ~300 km in diameter, which is required to account for all the thermal flux, although the occultation and thermal diameters are compatible within their error bars given the considerable uncertainty of the thermal results. The existence of a potential satellite also appears to be consistent with other ground-based data presented here. From the effective occultation diameter combined with absolute magnitude measurements we derive a geometric albedo of 0.147 {\textpm} 0.005, which would be somewhat smaller if 2002 TC302 has a satellite. The best occultation light curves do not show any signs of ring features or any signatures of a global atmosphere.

Tables A.1-A.3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/639/A134}, keywords = {astrometry, Astrophysics - Earth and Planetary Astrophysics, Kuiper belt objects: individual: 2002 TC302, Kuiper belt: general, Occultations, techniques: photometric}, isbn = {0004-6361}, url = {https://ui.adsabs.harvard.edu/abs/2020A\&A...639A.134O}, author = {Ortiz, J. L. and Santos-Sanz, P. and Sicardy, B. and Benedetti-Rossi, G. and Duffard, R. and Morales, N. and Braga-Ribas, F. and Fern{\'a}ndez-Valenzuela, E. and Nascimbeni, V. and Nardiello, D. and Carbognani, A. and Buzzi, L. and Aletti, A. and Bacci, P. and Maestripieri, M. and Mazzei, L. and Mikuz, H. and Skvarc, J. and Ciabattari, F. and Lavalade, F. and Scarfi, G. and Mari, J. M. and Conjat, M. and Sposetti, S. and Bachini, M. and Succi, G. and Mancini, F. and Alighieri, M. and Dal Canto, E. and Masucci, M. and Vara-Lubiano, M. and Guti{\'e}rrez, P. J. and Desmars, J. and Lecacheux, J. and Vieira-Martins, R. and Camargo, J. I. B. and Assafin, M. and Colas, F. and Beisker, W. and Behrend, R. and Mueller, T. G. and Meza, E. and Gomes-Junior, A. R. and Roques, F. and Vachier, F. and Mottola, S. and Hellmich, S. and Campo Bagatin, A. and Alvarez-Candal, A. and Cikota, S. and Cikota, A. and Christille, J. M. and P{\'a}l, A. and Kiss, C. and Pribulla, T. and Kom{\v z}{\'\i}k, R. and Madiedo, J. M. and Charmandaris, V and Alikakos, J. and Szak{\'a}ts, R. and Farkas-Tak{\'a}cs, A. and Varga-Vereb{\'e}lyi, E. and Marton, G. and Marciniak, A. and Bartczak, P. and Butkiewicz-Bak, M. and Dudzi{\'n}ski, G. and Al{\'\i}-Lagoa, V. and Gazeas, K. and Paschalis, N. and Tsamis, V. and Guirado, J. C. and Peris, V. and Iglesias-Marzoa, R. and Schnabel, C. and Manzano, F. and Navarro, A. and Perell{\'o}, C. and Vecchione, A. and Noschese, A. and Morrone, L.} }