Letter to the Editor

Three fast-rotating Jovian trojans identified by TESS set new population density limits

¹ Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, Konkoly Thege Miklós út 15-17 H-1121 Budapest, Hungary
² CSFK, MTA Centre of Excellence, Budapest, Konkoly Thege Miklós út 15-17 H-1121, Hungary
³ ELTE Eötvös Loránd University, Institute of Physics and Astronomy, Pázmány Péter sétany 1/A, Budapest, Hungary
⁴ ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, Szent Imre h. u. 112, 9700 Szombathely, Hungary
⁵ MTA-ELTE Exoplanet Research Group, Szent Imre h. u. 112, 9700 Szombathely, Hungary
⁶ Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA

^⋆ Corresponding author; pkisscs@konkoly.hu

Received: 18 December 2024
Accepted: 30 January 2025

Abstract

We report on the identification of the three fastest rotating Jovian trojans with reliable population assignments known to date, discovered using light curve data from the Transiting Exoplanet Satellite Survey mission and confirmed by Zwicky Transient Facility data. For two of our targets the rotation periods are moderately below the previously accepted ∼5 h Jovian trojan breakup limit (4.26 and 4.75 h); however, the rotation period of (13383) was found to be P = 2.926 h, leading to a density estimate of ρ ≈1.6 g cm⁻³, higher than the generally accepted ≲1 g cm⁻³ density limit of Jovian trojans. If associated with lower densities, this rotation rate requires considerable cohesion, of the order of a few kilopascals. The relatively high albedo (p_V ≈ 0.11) and fast rotation suggest that (13383) may have undergone an energetic collision that spun up the body and exposed bright material to the surface.