gas giant Archives - Page 3 of 12 - Astrobiology

Planetary radius as a function of time for different bulk metallicities (coloured lines; see legend). The solid lines are calculated from evolution models. The dashed lines use the heuristic that each 1% change in radius can accommodate about a 2% change in bulk metallicity -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Gas Giants, Status Report

Deep Radiative Zones Affect The Planetary Cooling And Internal Structure: Implications For Exoplanet Characterisation

by Keith CowingMarch 29, 2026March 29, 2026

The thermal evolution and interior structure of giant exoplanets are sensitive to the treatment of radiative opacity. At temperatures of ~2000 K, depletion of alkali metals can create a window […]

Best-fit orbit solutions. Here we show the on-sky orbit traced by Eps Ind Ab in panel (a); the evolution of on-sky separation and position angle of the planet during our observational baseline in panels

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report

A Second Visit To Eps Ind Ab With JWST: New Photometry Confirms Ammonia And Suggests Thick Clouds In The Exoplanet Atmosphere Of The Closest Super-Jupiter

by Keith CowingMarch 12, 2026March 12, 2026

With JWST, we are directly imaging cold (~200-300K), solar-age giant exoplanets for the first time.

Distribution of companions in semi-major axis and mass, along with the occurrence rate density of subsamples. (a), Detection efficiency-weighted KDE and distribution of our sample (white points). We divide the sample into low-mass and high-mass subsamples, with the division marked by a dashed red line at 30MJ. Detection efficiencies of 20% is outlined by a black contour. (b), The occurrence rate density vs companion mass (dN/d ln m per 100 stars). The best-fit log-normal plus power-law model with its uncertainty is overplotted. The uncertainties correspond to the 16th and 84th percentiles of the posterior distributions. (c), The occurrence rate density vs semi-major axes (dN/d ln a per 100 stars), when companion mass above 30MJ. (d), similar to c but for companions with m < 30MJ.

Brown Dwarfs, Exoplanets, -moons, -comets, Gas Giants, Status Report, Stellar Cartography

A Universal Brown Dwarf Desert Formed Between Planets And Star

by Keith CowingMarch 5, 2026March 5, 2026

Giant planets and brown dwarfs play a crucial role in star and planet formation, as they are situated at the boundary between planets and stars with uncertain formation mechanisms.

Recovery of an injected signal for the cloud-free case of V1298 Tau b on a vrest − KP grid for each synthetic night simulated using Ratri for the case of (top row) the optimistic detrending scenario and (bottom row) the non-reprocessing scenario where the SVD+MLR based detrending is followed by cross-correlation with a template model with no reprocessing performed on it. The injected signal is successfully detected in all three nights for the optimistic detrending scenario. For the non-reprocessing scenario, the injected signal is successfully detected only in Night 3 but with weaker constraints on KP compared to the optimistic detrending case. For the other two nights, the signal is either completely removed by the detrending scenario resulting in a non-detection (Night 1) or a detection at a much higher value of KP compared to the injected value (Night2). For more discussion about confidence intervals and what constitutes a detection, please see Section 2.4.3. -- astro-ph.EP

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

Probing The Atmospheres Of Young Long-Period Sub-Neptune Progenitors With ELT/ANDES

by Keith CowingMarch 1, 2026March 1, 2026

High-resolution cross-correlation spectroscopy (HRCCS) has emerged as a powerful technique for detecting and characterizing exoplanet atmospheres from the ground.

Orbital eccentricity (in e2) versus semi-major axis for the planet sample with eccentricities constrained to better than 40% for clarity (or if e < 0.1). Colors denote sub-Neptunes (1–4 R⊕, blue), sub-Saturns (4–8 R⊕, purple), and Jovians (8–16 R⊕, orange). Overlaid curves show theoretical formation channels from R. I. Dawson & J. A. Johnson (2018) for a fiducial planet of ∼6 R⊕ and ∼80 M⊕: high-eccentricity migration (red shaded region) and planet-planet scattering (gray dashed line, gray shaded region). The concentration of larger planets at high eccentricities and small semi-major axes is consistent with high-eccentricity migration. -- astro-ph.EP

Exoplanets, -moons, -comets, Status Report, Stellar Cartography

The Orbital Eccentricity–Radius Distribution for Warm, Single Planets in TESS

by Keith CowingFebruary 25, 2026February 25, 2026

We characterize the radius-dependent eccentricity distribution of 347 warm (P = 8-200 days) systems with only one transiting planetary candidate identified during Sectors 1-69 of the TESS mission.

Artist's impression of the planetary system around the star LHS 1903. Credit: ESA

Exoplanets, -moons, -comets, Gas Giants, Press Release, Stellar Cartography

Study Reveals A Planetary System With An Unexpected Rocky Planet In Its Outer Region

by Keith CowingFebruary 16, 2026February 16, 2026

An international scientific team, led by the University of Warwick and involving the Canary Islands Institute of Astrophysics, has used the European Space Agency’s Cheops satellite to discover that the […]

Planet mass (or minimum mass) as a function of orbital period for planetary systems hosting cold Jupiters.

Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Ice Giant, Icy Worlds, Status Report, Stellar Cartography

TESS Planets In Known Radial Velocity Cold Jupiter Systems: Hot Super Earth Occurrence Is Enhanced By Cold Jupiters

by Keith CowingFebruary 14, 2026February 14, 2026

The correlation between inner super-Earths (SEs) and outer cold Jupiters (CJs) provides an important constraint on the formation and dynamical evolution of planetary systems. Previous studies have suggested a positive […]

Cheops open questions: How do planets form?

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Ice Giant, Press Release, Stellar Cartography

Cheops Discovers Late Bloomer Planet From Another Era

by Keith CowingFebruary 13, 2026February 13, 2026

Many Vile Earthlings Munch Jam Sandwiches Under Newspapers and My Very Educated Mother Just Served Us Nachos. What sounds like gibberish half-sentences are memory aids taught to children to help […]

Schematic of some of the key processes throughout planet formation that influence carbon supply and retention. (a) Key ice/grain sublimation fronts in the disk noted (CO2 between water–CO and that of Silicates at inner disk edge not shown). Planets forming in these locations will receive different compositions at birth (Öberg et al. 2011). Dust that grows beyond the “soot” line (Lodders 2004, Kress et al. 2010, Li et al. 2021) will be rich in refractory carbon content and at greater distances molecular ices. (blow-out:) The drift of carbon-rich pebbles from the outer disk is a key process in carbon supply. Drift itself is influenced by pressure bumps that can lead to a pile-up of pebbles that can be potential sites for planetesimal and planet formation (shown on left side of disk). (b) Solids accrete ice mantles, sublimate key components at sublimation fronts and can collide leading to both growth and fragmentation. (c) Rocky planets and cores of gas-rich planets grow and gain carbon through accretion of pebbles (top) and/or planetesimals (bottom). Impacts of larger planetesimals can also strip atmospheric gas and also supply material. (d) heavy element differentiation can take carbon to the core, and the resulting magma ocean/atmosphere equilibrium can influence atmospheric composition with lighter gases escaping depending on the planet mass. Figure credit to N. Fuller and Sayo Studio. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Press Release

Carbon From Interstellar Clouds To Habitable Worlds

by Keith CowingFebruary 12, 2026February 12, 2026

Carbon is an essential element for a habitable world. Inner (r < 3 au) disk planetary carbon compositions are strongly influenced by supply and survival of carbonaceous solids. Here we […]

Time-lapse footage of a newly discovered exoplanet as it makes its slow journey around two stars. To obtain the image of the planet, astronomers needed to remove the stars' glare. Two star icons mark the locations of where the stars would be in relation to their planet. Credit Jason Wang/Northwestern University

Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Press Release, Science Fiction

Rare Image Of Tatooine-like Planet Is Closest To Its Twin Stars Yet

by Keith CowingDecember 14, 2025December 14, 2025

In a discovery that’s fit for a movie, Northwestern University astronomers have directly imaged a Tatooine-like exoplanet, orbiting two suns.