Stellar Cartography Archives - Page 8 of 30 - Astrobiology

[TOP] Time evolution of H2 mixing ratio for an atmosphere with 100% H2O. The heatmaps display vertical profiles over the 360-day simulation duration, with pressure (in bars) on the y-axis and time (in days) on the x-axis. The upper row shows results from the YMDF and FF models, while the bottom row corresponds to the FF 400 K and the CF model, as indicated on the panels. [BOTTOM] Heatmaps of CH4 mixing ratio in the atmosphere with 1% H2O over the 360-day simulation period for an atmosphere containing 100% water vapour analogous to the previous Fig. 8 -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Space Weather & Heliophysics, Status Report, Stellar Cartography

Stellar Flare-driven Evolution Of Primordial Early Exo-Earth Atmospheres: Insights From A Young M Dwarf Flare Model

by Keith CowingApril 23, 2026April 23, 2026

Context. M dwarfs are key targets for terrestrial exoplanet studies, with prospects for atmospheric spectroscopy. However, strong stellar magnetic activity and frequent flaring require modelling efforts to assess their impact […]

Isolines of planet radius versus mass, extracting cross-sections from our grid of models by holding other variables constant (top-right text box). Top (a): sensitivity to instellation (colour) and atmosphere mass fraction 𝑓𝑎 (line width, five values). Bottom (b): sensitivity to atmospheric metallicity log10 𝑍𝑎 (colour) and 𝑓𝑎 (line width, five values). For visualisation, only five sets of secondary variables (line widths) are shown. Dashed blue lines show airless cases with different core sizes (Zeng et al. 2019). -- astro-ph.EP)

Exoplanets, -moons, -comets, Habitable Zones, Press Release, Stellar Cartography

Beyond The Mass-radius Plane: Integrated Radiative-convective And Interior Structure Simulations Of The Exoplanet Continuum

by Keith CowingApril 23, 2026April 23, 2026

Static structure models, which map mass-radius constraints to bulk planet composition, are frequently used to categorise exoplanets due to their computational efficiency and the high-level insight they offer into planetary […]

Exoplanet 29 Cygni b, seen in this artist’s concept, is a gas giant weighing about 15 times the mass of Jupiter. It orbits a type A star (shown at upper right) slightly hotter and more massive than our Sun, at an average distance of 2.4 billion kilometres.-- Credit: NASA, ESA, CSA, J. Olmsted (STScI)

Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Status Report, Stellar Cartography

Webb Redefines The Dividing Line Between Planets And Stars

by Keith CowingApril 14, 2026April 14, 2026

Planets, like those in our Solar System, form in a bottom-up process where small bits of rock and ice clump together and grow larger over time. But the heftier the […]

Mass-radius relation (a) and orbital period vs. radius (b) of observed giant exoplanets with masses between 0.1 and 10 M𝐽 . The data is coloured according to the equilibrium temperature. Hexagons show the warm giant exoplanets with 𝑇eq < 1000 K, and hot Jupiters are shown as small circles in the background. The mass-radius diagram shows the 0.1, 1 and 10 g/cc isochores for reference. For a comparison, Jupiter (X) and Saturn (Y) are drawn with their respective symbols. Panels (c) and (d) show the inferred relation between the planet mass (between 0.3 and 2 M𝐽 ) and their heavy-element masses and metallicities. The symbols and colours indicate the host-star type: Green circles for FGK stars and blue hexagons for M dwarfs. The lines and shaded regions show the best fit and the 1 to 2 𝜎 contours. The data were taken from the PlanetS catalog (Parc et al. 2024) and M¨uller & Helled (2025). -- astro-ph.EP

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

Long-period Transiting Exoplanets: Advances In Detection And Characterization

by Keith CowingApril 14, 2026April 14, 2026

Most detected transiting planets have orbits which would fit within the one of Mercury, exposing them to intense stellar irradiation and interactions that significantly alter their properties.

PSF-subtracted images of all targets. The observation subarray of each target is indicated. The first seven images are zoomed in to area of 11.0” × 11.0” for clearer view of the central regions. For the last three targets, the small size (4.4” × 4.4”) is due to the choice of the observation subarray. The location of the star PSF center is denoted by the white cross. Sources around LHS 1478, TOI-1468, and TOI-270 are labeled with letters, which are likely background sources. The arrow near HD 260655 indicates a low-S/N identification of possible close companion. We further examined this detection in Section 4.4. North is up and east is to the left. -- astro-ph.EP

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

A Search For Wide-orbit Planets Around M-dwarfs Using Deep MIRI 15-micron Images

by Keith CowingApril 12, 2026April 12, 2026

Wide-orbit (>10 AU) gas giant planets shape the architecture of planetary systems, yet their occurrence rate remains poorly constrained.

Plotted here are the Kepler confirmed planets/candidates with Gaia DR2 radius improvements. Selection criteria are main-sequence host-star with temperature 5000-6500 K and planet radius errors less than ±10%. Data source: exoplanet archive (Akeson et al. 2013) (Christiansen et al. 2025) (Thompson et al. 2017) and Gaia DR2 Berger et al. (2020, 2018); Brown et al. (2018); Lindegren et al. (2018). Sub-Panels: (1): 1100+ planets fulfilling the criteria, with gray ellipse showing the typical errors in planet radius and temperature. (2) and (3): Smooth Kernel fit to data. (4): All known transiting Hot Jupiters (Rp > 8 R⊕) which have masses measured from RV surveys (e.g. WASP, HAT, HAT-P, etc.), colored by metallicity ([Fe/H]). also c.f. (Castro-González et al. 2024). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography

Exoplanet Orbital Distribution Around FGK Sun-like Host Stars I: Planet Occurrence Rate Derived From The Kepler Mission And Theoretical Interpretations From Planet Formation

by Keith CowingApril 11, 2026April 11, 2026

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) […]

Main plot: mass-radius plot of well-studied exoplanets from TepCat in between 1-20 Earth masses and 1-4 Earth radii. Some theoretical mass-radius curves are shown for comparison. Although a subset of planets is below the silicate (i.e. pure rock) curve and can be identified as rocky planets, a larger proportion of the planets is above this curve. In particular, they exhibit a clustering in the range of 6-10 Earth masses as shown by the background with 2D probability density contours and shading. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography

Exoplanet Orbital Distribution Around FGK Sun-like Host Stars II: A Valley In The Orbital Semi-major Axis Distribution Of Sub-Neptunes

by Keith CowingApril 10, 2026April 10, 2026

More than one hundred years ago, physics has been revolutionized when people realized that electronic orbitals, or electromagnetic interactions in general, are quantized. Now, in this study, we are presenting […]

The transit fitting results for KOI-1300.01. The upper right panel shows the phase-folded and contamination-corrected transit lightcurve for the planet’s circumprimary case. The gray circles are the normalized and contamination corrected flux values. The blue squares are the normalized flux values obtained from binning 800 data points at a time. The red line is the model fit to the data. The lower right panel shows the same information for the circumsecondary case. The upper left panels shows the corner plots from the MCMC sampling in the circumprimary case. The lower left shows the corner plots for the circumsecondary case. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report, Stellar Cartography

Determining the Host Stars of Planets in Binary Star Systems with Asterodensity Profiling: Investigating the Canonical Radius Gap

by Keith CowingApril 9, 2026April 9, 2026

Over the past 30 years, thousands of exoplanets have been discovered, revealing detailed demographics of planets outside the Solar System.

The left plots show the results of our injection and recovery test into our JWST observation of TOI 700 d, and the right for e.

Analog Studies, Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

The JWST Search For Earth-Luna Analogs: Upper Limits On Exomoons And Refined Ephemerides For TOI 700 d And e

by Keith CowingApril 8, 2026April 8, 2026

While no conclusive detections of exomoons have been reported to date, planet formation theories predict that satellites should be a common outcome of the collisional dynamics in early extrasolar systems.

Secular evolution of the obliquities of TOI-1710 from four-body secular integrations. The semimajor axis of the intermediate companion varies across panels. The obliquity evolution of TOI-1710 A b (red) and the hypothetical intermediate companion X (blue) are shown. The companion mass is fixed at 9 MJ and the initial mutual inclination with the M-dwarf is iXB = 55◦ . The green region marks the 2σ constraints on the obliquity of the observed planet, with the fraction of time spent within this region indicated by fobs. Panels (a) and (c) remain within the allowed window for much less time than panel (b). In all cases, the eccentricity of planet b remains nearly the same as the initial value. -- astro-ph.EP

Exoplanets, -moons, -comets, Gas Giants, Icy Worlds, Status Report

POSEIDON II: The Anti-Aligned Orbit of the Warm Neptune TOI-1710 A b

by Keith CowingApril 7, 2026April 7, 2026

We present an observation of the Rossiter-McLaughlin effect for the warm-Neptune system TOI-1710 obtained with the NEID spectrograph on the WIYN 3.5 m telescope.