KMT-2022-BLG-0475Lb and KMT-2022-BLG-1480Lb: Microlensing ice giants detected via the non-caustic-crossing channel

Abstract

Aims. We investigate the microlensing data collected in the 2022 season from high-cadence microlensing surveys in order to find weak signals produced by planetary companions to lenses. Methods. From these searches, we find that two lensing events, KMT-2022-BLG-0475 and KMT-2022-BLG-1480, exhibit weak short-term anomalies. From a detailed modeling of the lensing light curves, we determine that the anomalies are produced by planetary companions with a mass ratio to the primary of q ~ 1.8 × 10−4 for KMT-2022-BLG-0475L and q ~ 4.3 × 10−4 for KMT-2022-BLG-1480L. Results. We estimate that the host and planet masses and the projected planet-host separation are (Mh/M⊙, Mp/MU, a⊥/au) = (0.43−0.23+0.35, 1.73−0.92+1.42, 2.03−0.38+0.25) for KMT-2022-BLG-0475L and (0.18−0.09+0.16, 1.82−0.92+1.60, 1.22−0.14+0.15) for KMT-2022-BLG-1480L, where MU denotes the mass of Uranus. The two planetary systems have some characteristics in common: the primaries of the lenses are early-mid M dwarfs that lie in the Galactic bulge, and the companions are ice giants that lie beyond the snow lines of the planetary systems.