Gas Giants Archives

Schematic diagram of our preferred scenario. Red circles are planetesimals (and their fragments) from the terrestrial planet region. The black solid curves roughly denote the boundary of the current asteroid inner main belt. Eccentricity increases from bottom to top. Each panel shows the proposed evolution of the inner Solar System at different time ranges: (A) Formation and cooling of the EL planetesimal in the terrestrial planet region before 60 Myr after Solar System formation. In this period, the terrestrial planets began scattering planetesimals to orbits with high eccentricity and semimajor axes that correspond to the asteroid main belt. (B) Between 60 and 100 Myr, the EL planetesimal was destroyed by an impact in the terrestrial planet region. At least one fragment (the Athor family progenitor) was scattered by the terrestrial planets into the scattered disk, as in (A), then the giant planet instability implanted it into the inner main belt by decreasing its eccentricity. (C) A few tens of millions of years after the giant planet instability occurred, a giant impact between the planetary embryo Theia and proto-Earth formed the Moon. (D) The Athor family progenitor experienced another impact event that formed the Athor family at ~1500 Myr. -- Science

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Comets and Asteroids, Gas Giants, Meteorites & Asteroids, Press Release

Dating The Solar System’s Giant Planet Migration Using Chondrite Meteorites

by Keith CowingApril 16, 2024April 16, 2024

The period of orbital instability that led to the migration of the Solar System’s giant planets to their current orbit occurred between 60 and 100 million years after the beginning […]

We show the transmission spectrum for each reduction in the top panel and the differences between the reductions (in units of sigma) in the bottom panel. All three of our reductions agree per-point, at the ∼2σ level or better, with a median difference of 6ppm. -- astro-ph.EP

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

JWST COMPASS: A NIRSpec/G395H Transmission Spectrum Of The Sub-Neptune TOI-836c

by Keith CowingApril 2, 2024

Planets between the sizes of Earth and Neptune are the most common in the Galaxy, bridging the gap between the terrestrial and giant planets in our Solar System.

This is an artist's concept of a brown dwarf. NASA, ESA, Joseph Olmsted (STScI)

Astronomy & Telescopes, Brown Dwarfs, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Press Release

Hubble Finds That Brown Dwarf Binary Pairs Are Extremely Rare

by Keith CowingMarch 23, 2024March 23, 2024

It takes two to tango, but in the case of brown dwarfs that were once paired as binary systems, that relationship doesn’t last for very long, according to a recent […]

Left: Average completeness map for the super-Earth RV sample with detected gas giants overplotted in teal. Right: Average completeness map for the super-Earth transit sample with detected gas giants overplotted in teal. Color scale represents detection probability. On average, the RV sample has higher completeness to distant gas giants typically driven by much longer time baselines and more data points. Accounting for differences in individual system sensitivity as well as these broad trends between transit and RV samples is key to calculating frequencies of gas giants in our sample of super-Earth systems. -- astro-ph.EP

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

Strong Correlation Between Inner Super-Earths And Outer Gas Giant

by Keith CowingMarch 15, 2024

The connection between outer gas giants and inner super-Earths reflects their formation and evolutionary histories. Past work exploring this link has suggested a tentative positive correlation between these two populations, […]

(A) Three idealized Jovian thermal models, dry adiabatic (black), sub-adiabatic (orange) and super-adiabatic (blue). The non-adiabatic temperature gradient is ± 0.15 �/km. The grey dashed lines show the contribution functions of 10, 5.2, 2.6, and 1.25 GHz channels (from top to bottom). (B) Nadir brightness temperature anomalies at six Juno MWR channels. From top to bottom, they are at 22 GHz, 10 GHz, 5.2 GHz, 2.6 GHz, 1.25 GHz, and 0.6 GHz, respectively. The horizontal error bars show a conservative 2% uncertainty. The contribution 5 functions for 22 GHz and 0.6 GHz peak at pressures outside the range of the graph. (C) Limbdarkening anomalies (evaluated at a 45-degree emission angle). The horizontal error bars show a 0.1% instrument noise level (Janssen et al., 2005, 2017). -- astro-ph.EP

Atmospheres, Climate, Weather, Brown Dwarfs, Exoplanets, -moons, -comets, Gas Giants, Jupiter, Status Report

Super-adiabatic Temperature Gradient at Jupiter’s Equatorial Zone and Implications For Water Abundance

by Keith CowingMarch 12, 2024March 12, 2024

The temperature structure of a giant planet was traditionally thought to be an adiabat assuming convective mixing homogenizes entropy.

The plots of stellar metallicity ([Fe/H]) versus planetary orbital period for all transiting planets from the NASA exoplanet archive. Tranet stands for transiting planet. The transiting planets are split into four groups based on the multiplicity of their systems and are placed on four different panels. The two dotted vertical lines split the metallicity range into three metallicity regions, namely, sub-solar, solar, and super-solar. While low-multiplicity systems are evenly distributed across hosts of all metallicities there is a paucity of high-multiplicity systems around hosts of high metallicity indicating the effect of cold Jupiters on the inner planet multiplicity. -- astro-ph.EP

Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography

Constraining Planetary Formation Models Using Conditional Occurrences of Various Planet Types

by Keith CowingFebruary 28, 2024February 28, 2024

We report the conditional occurrences between three planetary types: super-Earths (m sin i < 10 M⊕, P < 100 days), warm Jupiters (m sin i > 95 M⊕, 10 < […]

Maps of the ring’s flux and brightness temperature as functions of ring radius and wavelength derived from the MIRI observations. The radial extent of the three main rings are shown at the far right of each plot (the Cassini Division is situated between the A and B rings). Note that the brightness temperature is more useful on the right-hand side of the figure, where thermal emission dominates over reflected sunlight. The brightness temperature rapidly increases at short wavelengths because of the increasing contribution of reflected sunlight. Narrow spectral features in the regions indicated by the shaded bands around 8 µm, 12 µm and 14µm are due to stray light from Saturn, but the bright line at 9.2 µm is due to the presence of highly crystalline water ice throughout the ring. -- astro-ph.EP

Gas Giants, Icy Worlds, Imaging & Spectroscopy, Press Release, Saturn

Water-Ice Dominated Spectra of Saturn’s Rings and Small Moons from JWST

by Keith CowingFebruary 27, 2024February 27, 2024

JWST measured the infrared spectra of Saturn’s rings and several of its small moons (Epimetheus, Pandora, Telesto and Pallene) as part of Guaranteed Time Observation program 1247.

Observed UCD candidates on a zoomed Gaia MG - G − J and G − GRP diagrams: UCDs are coloured by their obtained spectral type, as explained in Sect. 3. The two circled UCDs have peculiar colours (see text). Subdwarfs candidates are represented by crosses (see Sect. 4.1). Peculiar objects are represented by triangles (Sect. 4.2). The UCDs with common parallaxes and proper motions with another system are represented by diamonds (see Sect. 4.3) and those in (potentially) unresolved binary systems by squares (Sect. 4.4). The grey points are the sources from the Gaia Catalogue of Nearby Stars, with a RUWE < 1.4. The insets illustrate the locus of our sample on entire GaiaCatalogue of Nearby stars colour-absolute magnitude diagrams. -- astro-ph.SR

Astronomy & Telescopes, Brown Dwarfs, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report, Stellar Cartography

Near-infrared Spectroscopic Characterisation Of Gaia Ultra-cool Dwarf Candidates; Spectral Types And Peculiarities

by Keith CowingFebruary 16, 2024February 16, 2024

Context: The local census of very low-mass stars and brown dwarfs is crucial to improving our understanding of the stellar-substellar transition and their formation history. These objects, known as ultra-cool […]

Maps of distribution of planets for each planet Type in the HESTIA Milky Way–Analogue for stars with M‹ “ 1M@. The assignment is based on the NEmbryo “ 50 NGPPS population. (a) Face-on view. -- astro-ph.EP

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

Populating The Milky Way: Characterising Planet Demographics by Combining Galaxy Formation Simulations and Planet Population Synthesis Models

by Keith CowingFebruary 15, 2024February 15, 2024

Stellar populations and their distribution differ widely across the Galaxy, which is likely to affect planet demographics.

Forward modelled spectrum for candidate HD 106315 c, binned to R=50 from 0.5-4.5 𝜇m. Molecular absorption components are shown at the binned resolution of the final spectrum. Also shown are the total contributions to the final spectrum from CIA (between H2-H2 and H2-He) and Rayleigh scattering (all atmospheric molecules), with the final spectrum shown in black. -- astro-ph.EP

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

Cool Gaseous Exoplanets: Surveying The New Frontier With Twinkle

by Keith CowingFebruary 14, 2024February 14, 2024

Cool gaseous exoplanets (1.75 R⊕<Rp<3 RJ, 200 K <Teq<1000~K) are an as-yet understudied population, with great potential to expand our understanding of planetary atmospheres and formation mechanisms.