Exomoon Archives

Four types of mutual events simulated for a phase angle of 225◦ . The RGB images are based on individual maps simulated for wavelengths of 440 nm (blue), 555 nm (green), and 700 nm (red). The total flux was normalized to the geometric albedo separately at each of the wavelengths. The dashed circles indicate the position and size of the planet (blue) and moon (gray). To improve the visibility of the moon and to fit both bodies into the images for shadow and eclipse, the lunar surface albedo am was increased to 0.3 and the moon’s semimajor axis was set to 2.8 rp for this graphic. -- astro-ph.EP

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

Polarimetry Of Exoplanet-Exomoon Systems

by Keith CowingApril 15, 2025April 15, 2025

We investigated the potential of polarimetric observations in the optical wavelength range for the detection of exomoons and the characterization of exoplanet-exomoon systems.

A comparison between the values of the various mean opacities defined by Eqns. 14-16, the wavelength dependence of the different radiation fields and actual cross-sections. The left panel sketches the conditions under which 𝛾 > 1 occurs when averaging opacity functions 𝜅 (𝜆) (solid black line). When irradiated by a stellar black-body, the opacity ratio of incoming to outgoing mean opacities is 𝛾 < 1 (the constant red value is below the constant green value). When the irradiating black-body cools, it moves up to the high opacity range in the infrared, but the outgoing radiation remains in the far-infrared, resulting in 𝛾 > 1 (the constant blue line is above the constant green one) and vigorous hydrodynamic escape occurs. The right panel shows that 𝜅out readily remains low for realistic and cold, molecules such as NH3, as the natural spacing between the molecular band peaks outpaces the width of a black-body. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Status Report, Titan

Efficient And Inefficient Hydrodynamic Escape of Exo-satellite Atmospheres Driven By Irradiation From Their Young Giant Planets

by Keith CowingMarch 26, 2025

The bolometric radiation from a central body is potentially a powerful driver of atmospheric escape from planets or satellites.

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.

Schematic diagram (not to scale) of four angular momentum vectors in the β Pictoris system: total angular momentum (Lˆ), orbital angular momentum of planets b and c (nˆorbit,b, nˆorbit,c), and the spin vector of planet b (nˆspin,b). The mutual inclination between nˆorbit,b and nˆorbit,c is ∼ 1 ◦. Secular spin-orbit resonance can occur when the period of orbit nodal regression (path along grey dotted circle on the left) has a similar period to the spin axis precession (path along black dotted circle on the right). The period of spin axis precession can be greatly shortened in the presence of a close-in equatorial exomoon, which acts as a lever and effectively extends the planet’s equatorial bulge. I is the orbital inclination of β Pictoris b (orange ellipse) relative to the invariable plane (grey ellipse). -- astro-ph.EP

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

A Potential Exomoon From The Predicted Planet Obliquity Of β Pictoris b

by Keith CowingDecember 17, 2024December 17, 2024

Planet obliquity is the alignment or misalignment of a planet spin axis relative to its orbit normal. In a multiplanet system, this obliquity is a valuable signature of planet formation […]

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

Exomoons Of Circumbinary Planets

by Keith CowingDecember 5, 2024December 5, 2024

Exomoon discovery is on the horizon. Although several exomoon candidates exist around single stars, there are currently no candidates around circumbinary planets (CBPs).

A comparison between the seven longest period (if fully confirmed at current values) candidates from this paper, and the KOI catalog (Thompson et al. 2018). Equilibrium temperatures and apparent magnitudes are taken directly from the respective TOI and KOI catalogs. Note that TOI1894’s period could be half what is reported. -- astro-ph.EP

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

Validating the Orbital Periods of the Coolest TESS Exoplanet Candidates

by Keith CowingNovember 27, 2024May 22, 2025

When an exoplanet passes in front of its host star, the resulting eclipse causes an observable decrease in stellar flux, and when multiple such transits are detected, the orbital period […]

Stability analysis of the TOI-561 planetary system. For fixed initial conditions (Table 2), the parameter space of the system is explored by varying the orbital period and the eccentricity of planet- 𝑓 . The step size is 0.25 day in the orbital period and 0.0025 in the eccentricity. For each initial condition, the system is integrated over 10 000 yr, and a stability indicator is calculated, which involved a frequency analysis of the mean longitude of the inner planet. The chaotic diffusion is measured by the variation in the main frequency. Red points correspond to highly unstable orbits, while blue points correspond to orbits that are likely to be stable on Gyr timescales. The black curve corresponds to 𝐾 = 1.88 m/s and the black dot shows the values of the best fit solution (Table 2). -- astro-ph.EP

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

Architecture Of TOI-561 Planetary System

by Keith CowingOctober 27, 2024October 27, 2024

We present new observations from CHEOPS and TESS to clarify the architecture of the planetary system hosted by the old Galactic thick disk star TOI-561.

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 […]

The age and configuration of the known planets in putative, icy exomoon-bearing Jupiter-like gas giant consisting of candidate exosystems. The size of the bubbles indicates the mass of the planets in MJup. The dotted, dashed, and solid black curves in the upper right corner of the plot show the estimated impact ratio in the case of Late Heavy Bombardment and are used as an indicator of higher probability bioaerosol ejection in space 28 (steady decrease impact flux: dotted and dashed lines, and single cataclysm - sensu stricto Late Heavy Bombardment: solid line scenarios) [51]. I.e. the curves may show the changing tendency in the probability of bioaerosol ejection and transportation in the case of various exosystems in the period marked by the transparent grey horizontal regions. -- astro-ph.EP

Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Impact events, Panspermia, Status Report

Searching For Jupiter And Saturn Analog Planets With Potential Icy Exomoons — A Panspermia Perspective

by Keith CowingJune 17, 2024June 17, 2024

Considering the possibility of complex organic molecules and microbial life appearing under the ice shell of those satellites in the Solar system, this study investigates the possible analog sources (targeting […]

Illustration of the proposed TEMPO survey’s field of view, focusing on the Orion Nebula Cluster (ONC) which has an age range of 1–3 Myr. The ONC is a region of intense star formation and offers a valuable window into the early stages of stellar and planetary evolution. Credit: ESO/H. Drass et al. -- astro-ph.EP

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

The TEMPO Survey II: Science Cases Leveraged from a Proposed 30-Day Time Domain Survey of the Orion Nebula with the Nancy Grace Roman Space Telescope

by Keith CowingJune 12, 2024June 12, 2024

The TEMPO (Transiting Exosatellites, Moons, and Planets in Orion) Survey is a proposed 30-day observational campaign using the Nancy Grace Roman Space Telescope.

Exomoon

Polarimetry Of Exoplanet-Exomoon Systems

Efficient And Inefficient Hydrodynamic Escape of Exo-satellite Atmospheres Driven By Irradiation From Their Young Giant Planets

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

A Potential Exomoon From The Predicted Planet Obliquity Of β Pictoris b

Exomoons Of Circumbinary Planets

Validating the Orbital Periods of the Coolest TESS Exoplanet Candidates

Architecture Of TOI-561 Planetary System

A Candidate High-Velocity Exoplanet System In The Galactic Bulge

Searching For Jupiter And Saturn Analog Planets With Potential Icy Exomoons — A Panspermia Perspective

The TEMPO Survey II: Science Cases Leveraged from a Proposed 30-Day Time Domain Survey of the Orion Nebula with the Nancy Grace Roman Space Telescope

Proba-3 Views Its Coronagraph – And Our Home World

Characterizing The Oxidation State Of Rocky Exoplanets With The Large Interferometer For Exoplanets (LIFE)

Exploring the Limits of Spectral Line Stacking in Spectral Line Data and Application Toward the Detection of Bulk 13C Enrichment of Aromatics in TMC-1

Stellar Activity, Exoplanet, Habitability, Planetary Atmospheres

Nondetection of Narrowband Radio Technosignatures from LHS 1140 b at 1–12 GHz