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arXiv · 2610.40106

Seven Years of TESS Precovery Observations of the Dwarf-planet Candidate 2026 ED$_{138}$

Te Han·Jeroen Audenaert·Daniel Muthukrishna·Matthew Holman·George R. Ricker
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Abstract

The trans-Neptunian object 2026 ED$_{138}$ was announced in 2026 October as the first dwarf-planet candidate in our solar system discovered by the Vera C. Rubin Observatory. The Transiting Exoplanet Survey Satellite (TESS) observed it in five month-long sectors between 2019 and 2026, four of them before its discovery. We subtract every Gaia DR3 star from these crowded full-frame images with the TESS-Gaia Light Curve (TGLC) package, then remove static residuals with a running median. Stacking the images along its predicted path detects 2026 ED$_{138}$ in all five sectors at 5-21$σ$, and at 34$σ$ combined. The TESS positions alone confirm the JPL orbit, and its brightness is consistent with the 0.08 mag fading expected from its increasing distance and changing phase angle.

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Te Han, Jeroen Audenaert, Daniel Muthukrishna, Matthew Holman, George R. Ricker. 2026-10-29. Seven Years of TESS Precovery Observations of the Dwarf-planet Candidate 2026 ED$_{138}$. https://arxiv.org/abs/2610.40106

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