A Saturn-mass free-floating-planet event

A population of free-floating planets is known from gravitational microlensing surveys. None of those planets have a directly measured mass, due to a degeneracy with the distance, though the population statistics indicate that many are less massive than Jupiter. We report a microlensing event, KMT-2024-BLG-0792/OGLE-2024-BLG-0516, which was observed from both ground- and space-based telescopes. This breaks the mass-distance degeneracy; we determine that the event was caused by a planet with 0.219+0.075-0.046 Jupiter masses, which is either gravitationally unbound or on a very wide orbit. By comparing to the statistical properties of other observed microlensing events and predictions from simulations, we infer that this object likely formed in a protoplanetary disk, not in isolation like a brown dwarf. Dynamical processes then ejected it from its birth place, producing a free-floating object.
, , # Data from: A Saturn-mass free-floating-planet event

Dataset DOI: [10.5061/dryad.g79cnp622](10.5061/dryad.g79cnp622)

## Description of the data and file structure

`gett.py`, gett version 1.0, a code used to model the terrestrial microlens parallax and diurnal microlens parallax effects.

`MIKE.fits`, in the standard Flexible Image Transport System (FITS) format for spectroscopic data, is the MIKE spectroscopic data product of KMT-2024-BLG-0792/OGLE-2024-BLG-0516 used in the spectral analysis.

The photometric data files for all sites used in the microlensing light-curve modeling of KMT-2024-BLG-0792/OGLE-2024-BLG-0516 are provided in .csv format. Each file contains three columns: mid-exposure time (\"BJD_TCB\"), given in Barycentric Julian Date (BJD)  with Barycentric Coordinate Time (TCB); magnitude (\"Mag\"); and error bar (\"Err\").  When performing the light-curve modeling, error bars are re-normalized as described in the \"Microlensing analysis\" section of \"Materials and Methods\". The...,