Related papers: Free-Floating Planets, the Einstein Desert, and 'O…

We show that the $P\sim8\,{\rm h}$ photometric period and the astrometrically measured $A_{\rm ng}\sim2.5\times10^{-4}\,{\rm cm\,s^{-2}}$ non-gravitational acceleration (at $r\sim1.4\,{\rm AU}$) of the interstellar object 1I/2017…

We present an ultra-deep survey for Neptune Trojans using the Subaru 8.2-m and Magellan 6.5-m telescopes. The survey reached a 50% detection efficiency in the R-band at 25.7 magnitudes and covered 49 square degrees of sky. This depth…

With its planet detection efficiency reaching a maximum for orbital radii between 1 and 10 AU, microlensing provides a unique sensitivity to planetary systems similar to our own around galactic and even extragalactic stars acting as lenses…

We report the light-curve analysis for the event MOA-2020-BLG-135, which leads to the discovery of a new Neptune-class planet, MOA-2020-BLG-135Lb. With a derived mass ratio of $q=1.52_{-0.31}^{+0.39} \times 10^{-4}$ and separation…

Recent astronomical observations, in particular from the Kepler and TESS missions and their related follow-ups, have revealed an abundance of exoplanets in the size range between Neptune (4 Earth radii) and Earth (1 Earth radii ), as well…

Extending the approach developed by Ara\'ujo and Stoeger [1] and improved in Ara\'ujo {\it et al} [2], we have shown how to construct dust-filled $\Lambda \neq 0$ Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) cosmological models from FLRW…

We present the analysis of four candidate short duration binary microlensing events from the 2006-2007 MOA Project short event analysis. These events were discovered as a byproduct of an analysis designed to find short timescale single lens…

Post-Newtonian theory was instrumental in conducting the critical experimental tests of general relativity and in building the astronomical ephemerides of celestial bodies in the solar system with an unparalleled precision. The cornerstone…

The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the…

We scrutinize the light sail scenario of the first interstellar object (ISO) 1I/2017 U1 (`Oumuamua) by making comparisons between physical models and observational constraints. These analyses can be generalized for future surveys of…

The Einstein rings and proper motions of nearby stars tend to be large. Thus, every year some foreground stars within a few hundred parsecs of Earth induce gravitational lensing events in background stars. In some of these cases, the events…

We present the discovery of a free-floating planet microlensing event KMT-2024-BLG-0816. The event shows finite-source effect, significant blending light, and no microlensing signal from a putative planet host. Among the free-floating…

We present the first measurement of planet frequency beyond the "snow line" for planet/star mass-ratios[-4.5<log q<-2]: d^2 N/dlog q/dlog s=(0.36+-0.15)/dex^2 at mean mass ratio q=5e-4, and consistent with being flat in log projected…

We analyze OGLE-2007-BLG-050, a high magnification microlensing event (A ~ 432) whose peak occurred on 2 May, 2007, with pronounced finite-source and parallax effects. We compute planet detection efficiencies for this event in order to…

We present the analysis of the light curves of 9 high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302,…

We constrain the abundance of primordial black holes (PBH) using 2622 microlensing events obtained from 5-years observations of stars in the Galactic bulge by the Optical Gravitational Lensing Experiment (OGLE). The majority of microlensing…

Extrasolar planets found by gravitational microlensing often require assumptions on the source star distance and relative proper motion. Only in a few cases has it been possible to confirm these findings with space-based observations or…

Motivated by the possibility that a coronagraph will be put on WFIRST/AFTA, we explore the direct detectability of extrasolar giant planets (EGPs) in the optical. We quantify a planet's detectability by the fraction of its orbit for which…

6500+ exoplanets have been detected using various techniques. This prompted the emergence of many recent works on the taxonomy, or classification, of exoplanets. However, there is still no basic, fundamental definition of 'What is a…

We present observations of microlensing event MACHO-98-BLG-35 which reached a peak magnification factor of almost 80. These observations by the Microlensing Planet Search (MPS) and the MOA Collaborations place strong constraints on the…