A1 Refereed original research article in a scientific journal
Predictions of the LSST Solar System Yield: Neptune Trojans
Authors: Murtagh, Joseph; Schwamb, Megan E.; Bernardinelli, Pedro H.; Lin, Hsing Wen; Kurlander, Jacob A.; Merritt, Stephanie R.; Cornwall, Samuel; Jurić, Mario; Fedorets, Grigori; Holman, Matthew J.; Eggl, Siegfried; Jones, R. Lynne; Yoachim, Peter; Moeyens, Joachim; Kubica, Jeremy; Oldag, Drew; West, Maxine; Chandler, Colin Orion
Publisher: Institute of Physics Publishing
Publication year: 2026
Journal: The Astronomical Journal
Article number: 90
Volume: 171
Issue: 2
ISSN: 0004-6256
eISSN: 1538-3881
DOI: https://doi.org/10.3847/1538-3881/ae27bd
Publication's open availability at the time of reporting: Open Access
Publication channel's open availability : Open Access publication channel
Web address : https://iopscience.iop.org/article/10.3847/1538-3881/ae27bd
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/515503344
Self-archived copy's licence: CC BY
Self-archived copy's version: Publisher`s PDF
The NSF-DOE Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST), beginning full operations in late 2025, will dramatically transform solar system science by vastly expanding discoveries and providing detailed characterization opportunities across all small-body populations. This includes the co-orbiting 1:1 resonant Neptune Trojans (NTs), which are thought to be dynamically hot captures from the protoplanetary disk. Using the survey simulator Sorcha, combined with the latest LSST cadence simulations, we present the very first predictions for the NT yield within the LSST. We forecast a model-dependent median number of ∼130–300 discovered NTs, and infer a notable 2:1 detection bias toward the recently emerged L5 cloud near the Galactic plane versus the L4 cloud, reflecting the lower-cadence coverage in the Northern Ecliptic Spur region that suppresses L4 detections. The additionally simulated Science Validation survey will offer the very first early insights into this understudied cloud. Around 60% of detected main survey NTs will meet stringent color light-curve quality criteria, increasing the sample size more than fourfold compared to existing datasets. This enhanced sample will enable robust statistical analyses of NT color and size distributions, crucial for understanding their origins and relationship to the broader trans-Neptunian population. These comprehensive color measurements represent a major step forward in characterizing the NT population and will facilitate future targeted spectroscopic observations.
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Funding information in the publication:
J.Mu. acknowledges support from the Department for the Economy (DfE) Northern Ireland postgraduate studentship scheme and travel support from the Science and Technology Facilities Council (STFC) for UK participation in LSST through grant No. ST/S006206/1. J.Mu. and J.A.K. thank the LSST-DA Data Science Fellowship Program, which is funded by LSST-DA, the Brinson Foundation, and the Moore Foundation; their participation in the program has benefited this work. M.E.S. acknowledges support in part from STFC UK grant Nos. ST/V000691/1 and ST/X001253/1. P.H.B., J.A.K., M.J., P.Y., J.Mu., and C.O.C. acknowledge the support from the University of Washington College of Arts and Sciences, Department of Astronomy, and the Data-intensive Research in Astrophysics and Cosmology (DiRAC) Institute. The DiRAC Institute is supported through generous gifts from the Charles and Lisa Simonyi Fund for Arts and Sciences, Janet and Lloyd Frink, and the Washington Research Foundation. M.J.H. gratefully acknowledges support from the NSF (grant No. AST2206194) and the NASA YORPD Program (grant No. 80NSSC22K0239). S.C. acknowledges that this work was supported in part by the Department of Education through the Graduate Assistance in Areas of National Need Fellowship Program award P200A240010 at the University of Illinois Department of Aerospace Engineering.
