microlensing Archives

Physical parameters of the simulated events with and without detected moons. In each panel, the grey points show the events our simulation where a moon was not detected, i.e., these are the distributions of the physical parameters of the planets and moons we simulated. The stars show events where the moon was detected. The blue markers indicate the locations of the light curves shown in Figure 6 in these parameter spaces. Each panel shows (a) the planet/star mass ratio versus planet projected separation in units of the Einstein ring radius of the system. The lines indicate the boundaries of the resonant caustic region that we exclude from our sample; (b) the planet mass versus the planet semimajor axis; (c) moon/planet mass ratio versus the moon-planet separation in units of the Einstein ring radius of the planet; (d) moon mass versus semimajor axis of the moon in units of the Hill radius. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. III. Detectability of Giant Exomoons of Wide Separation Giant Planets

by Keith CowingSeptember 7, 2025September 7, 2025

Roman should be sensitive to lenses with mass down to ~ 0.02 M⊕, or roughly the mass of Ganymede. Thus the detection of moons with masses similar to the giant […]

Keck NIRC2-LGS images of the two events. North is up and East is to the left. The green and red boxes indicate the target and comparison stars, respectively. Insets show zoomed-in views of each star, including the original image and the residuals following PSF subtraction, which are shown on the identical flux scale to facilitate comparison. The gray dotted circles in the residual images show the predicted lens-source separation. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb: Mass Measurements for Two Super-Earth Microlensing Planets

by Keith CowingAugust 29, 2025August 29, 2025

KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb were the lowest mass-ratio microlensing planets at the time of discovery. For both events, microlensing parallax measurements from the Spitzer Space Telescope implied lens systems that were […]

The magnification excess maps for planet-satellite configurations with log q = −1.5 and | log s| = 0.3. The color coding indicates fractional magnification differences between the 2L1S and 1L1S models. The maps with wide-separation (log s = 0.3) and close-separation (log s = −0.3) cases are displayed in the upper and lower panels, respectively. The left and right panels correspond to Earthmass and Neptune-class planets. The x-y coordinates denote the source positions in units of θE, with the positive x-axis aligned in the direction pointing from the planet (gold star) to the satellite (cyan star). Magenta circles indicate the source stars’ sizes (ρ = 0.33 for Earth-mass lenses and ρ = 0.08 for Neptune-class). Caustics are depicted in red, with the central caustic located near the planet and the satellite caustics positioned farther away. Each panel includes a lower-right inset offering a zoom-in view of the central caustics. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Detecting Exomoons In Free-Floating-Planet Events From Space-based Microlensing Surveys

by Keith CowingMay 30, 2025May 26, 2025

When a planet is ejected from its star-planet system due to dynamical interactions, its satellite may remain gravitationally bound to the planet.

Distribution of known exoplanet masses plotted vs. semi-major axis (left) and semimajor axis normalized to the location of the snow-line (right) at asnow = 2.7AU M/MSun (green dashed line). Planets found by the Doppler/RV method (black lines with upward error bars indicating the sin i uncertainty, where i refers to line-of-sight inclination), transits (blue squares), microlensing (red error bar crosses), direct detection, (magenta triangles) timing (green triangles) and transit timing variations (gold diamonds). Small cyan spots indicate Kepler planets and planet candidates without mass measurements. Black letters show the locations of our Solar System's planets. Microlensing discoveries. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Exoplanet Detection With Microlensing

by Keith CowingMay 20, 2025May 20, 2025

Microlensing is the method of exoplanet detection that discovers solar system analog exoplanets.

Earth-like Exoplanet - Grok via Astrobiology.com

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release

Astronomers Find Earth-like Exoplanets Are Common Across The Cosmos

by Keith CowingMay 9, 2025

Using the Korea Microlensing Telescope Network (KMTNet), an international team of researchers has discovered that super-Earth exoplanets are more common across the universe than previously thought, according to a new […]

Periods and mass ratios for planets detected using different methods. Data points show all exoplanets catalogued on 30 July 2023 (41) and are color-coded by detection method (see legend). The magenta star indicates OGLE-2016-BLG-0007Lb (error bars show 68% confidence intervals for this planet, but are omitted from all other planets). Colored images show six Solar System planets: Venus, Earth, Jupiter, Saturn, Uranus and Neptune. Filled magenta points are our collated sample of planets from the KMTNet microlensing survey (see text); empty magenta circles are other planets detected with the microlensing technique. The microlensing detections include planets with mass-ratios corresponding to super-Earths with Jupiter-like orbital periods. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Microlensing Events Indicate That Super-Earth Exoplanets Are Common In Jupiter-like Orbits

by Keith CowingMay 2, 2025

Exoplanets classified as super-Earths are commonly observed on short period orbits, close to their host stars, but their abundance on wider orbits is poorly constrained. Gravitational microlensing is sensitive to […]

This artist’s concept visualizes a super-Neptune world orbiting a low-mass star near the center of our Milky Way galaxy. Scientists recently discovered such a system that may break the current record for fastest exoplanet system, traveling at least 1.2 million miles per hour, or 540 kilometers per second. NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar, Press Release, Stellar Cartography

The Fastest Exoplanet System Yet Discovered

by Keith CowingFebruary 11, 2025February 11, 2025

Astronomers may have discovered a scrawny star bolting through the middle of our galaxy with a planet in tow. If confirmed, the pair sets a new record for the fastest-moving […]

The Chinese Space Station Telescope (CSST) - CNSA/Xinhua

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Chinese Space Station Telescope: Detecting Exomoons in Free-Floating-Planet Events from Space-based Microlensing Surveys

by Keith CowingJanuary 9, 2025January 9, 2025

When a planet is ejected from its star-planet system due to dynamical interactions, its satellite may remain gravitationally bound to the planet.

Light curves of the microlensing event OGLE-2015-BLG-1609 with three microlensing model topologies for positive values of the impact parameter u0. The difference between the topologies is visible only during the planetary anomaly (HJD ∼ 2457270; see Fig. 2). The photometry comes from the OGLE, MOA, RoboNet, and MiNDSTEp projects. -- astro-ph.EP

Astronomy & Telescopes, Brown Dwarfs, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

OGLE-2015-BLG-1609Lb: Sub-jovian Planet Orbiting A Low-mass Stellar Or Brown Dwarf Host

by Keith CowingDecember 18, 2024December 18, 2024

We present a comprehensive analysis of a planetary microlensing event OGLE-2015-BLG-1609. The planetary anomaly was detected by two survey telescopes, OGLE and MOA.

Left: A zoom-in on the stacked Kp-band image of MOA-2011-BLG-262, with the brighter source star near center and the faint lens star candidate indicated with the cross-hair. Middle: Zoomed-in frame with a single-PSF model fit to the source star and subtracted from the frame, the remaining flux comes primarily from the lens and is indicated with the cross-hair. The other bright nearby stars are also subtracted with the same PSF model. Right: Zoomed-in frame with the PSF model fit and subtracted from the source and lens stars. North is up, East is left in all frames. Note there are several faint ambient field stars that are at or below the default detection threshold in DAOPHOT. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gaia Mission, Gas Giants, Imaging & Spectroscopy, Interstellar, Status Report, Stellar Cartography

A Candidate High-Velocity Exoplanet System In The Galactic Bulge

by Keith CowingOctober 16, 2024November 16, 2024

We present an analysis of adaptive optics (AO) images from the Keck-I telescope of the microlensing event MOA-2011-BLG-262. The original discovery paper by Bennett et al. 2014 reports two distinct […]

microlensing

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. III. Detectability of Giant Exomoons of Wide Separation Giant Planets

KMT-2018-BLG-0029Lb and OGLE-2019-BLG-0960Lb: Mass Measurements for Two Super-Earth Microlensing Planets

Detecting Exomoons In Free-Floating-Planet Events From Space-based Microlensing Surveys

Exoplanet Detection With Microlensing

Astronomers Find Earth-like Exoplanets Are Common Across The Cosmos

Microlensing Events Indicate That Super-Earth Exoplanets Are Common In Jupiter-like Orbits

The Fastest Exoplanet System Yet Discovered

Chinese Space Station Telescope: Detecting Exomoons in Free-Floating-Planet Events from Space-based Microlensing Surveys

OGLE-2015-BLG-1609Lb: Sub-jovian Planet Orbiting A Low-mass Stellar Or Brown Dwarf Host

A Candidate High-Velocity Exoplanet System In The Galactic Bulge

Underwater Oxygen Loss Threatens Earth’s Stability, Researchers Warn

Fire And Ice: Were Yellowstone’s Past Volcanic Eruptions And Glaciations Related?

Substrate-Agnostic 3x: Biosignatures, Technosignatures, Ecologies

Planet-moon Ejections In Close Stellar Encounters

First Study Hints Solar Storms May Alter The Weather During Martian Dust Storms