KMT-2025-BLG-1616Lb: First Microlensing Bound Planet From DREAMS

Abstract

We present observations and analysis of the bound planetary microlensing event KMT-2025-BLG-1616. The planetary signal was captured by the Korea Microlensing Telescope Network (KMTNet) and the DECam Rogue Earths and Mars Survey (DREAMS). DREAMS's minute-cadence observations break the central/resonant degeneracy in the binary-lens models. The color of the faint source star ($I=22$) is measured from the DREAMS's $r-z$ color. The planetary system has a planet-host mass ratio of $q\sim 5\times 10^{-4}$. A Bayesian analysis yields a host-star mass of $\sim 0.3M_{\odot }$, a planetary mass of $\sim 40M_{\oplus }$, a projected planet-host separation of $\sim 1.6\mathrm{au}$, and a lens distance of $\sim 7.5\mathrm{kpc}$. Based on the photometric precision achieved by DREAMS for this event, we simulate free-floating planet (FFP) detections and find that DREAMS is sensitive to Mars-mass FFPs in the Galactic bulge and Moon-mass FFPs in the Galactic disk.

Accepted for publication in AJ