hot jupiter Archives

Raw B band polarization measurements of HD 189733 obtained at Gemini North on UT 1 to 7 Aug 2018, which are dominated by observations on the last night (gold points). Top left: Stokes q (linear polarization) modulation as a function of parallactic angle. Telescope linear polarization is modulated by parallactic angle with amplitude ∆(qTP, uTP) = 0.2620±0.0034% (Wiktorowicz et al. 2023), where the best fit curve from Equation 2a is shown in black. Uncertainties in most data points are smaller than the size of the data points. Top right: Same as at top left but for Stokes u (linear polarization, Equation 2b). Bottom left: Same as at top left but for Stokes v (circular polarization, Equation 2c). Bottom right: Temporal variation of parallactic angle, which rotates rapidly as the target crosses the meridian (black dashed lines) around 20:00 LST. This rapid meridian crossing provides the bulk of the telescope polarization modulation necessary for accurate calibration. -- astro-ph.EP

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

A Scatter of Light from a Polarized World

by Keith CowingSeptember 25, 2025

Many known exoplanets harbor clouds, which lead to degeneracies in spectroscopic models between particle composition and size. Polarimetry, however, provides independent assessment.

Observed spectra after dividing by the out-of-transit spectrum (residuals), shown in the stellar rest frame. Vertical orange and green dotted lines indicate the positions of the Na D2 and D1 lines, respectively. The region between the two horizontal dotted lines corresponds to in-transit observations, while regions outside represent out-of-transit data. The tilted red lines at the positions of Na D2 and D1 indicate the expected shift of the planetary absorption signal. -- astro-ph.EP

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

An Initial Assessment Of The Hanle Echelle Spectrograph For Exoplanet Atmosphere Studies

by Keith CowingSeptember 24, 2025September 24, 2025

Transmission spectroscopy is an effective technique for probing exoplanetary atmospheres.

The radial gas temperature maps of planets from the 3D AFGKM ExoRad with a global temperature, Tglobal of 800K (left), 1600K (center) and 2400K (right) that orbit different host stars (top to bottom: A, G, M). The (Tgas, pgas)-maps gas are shown as equatorial slice plots. -- astro-ph.EP

AI - Data - Apps - Cybernetics, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Status Report

Accelerating Exoplanet Climate Modelling: A Machine Learning Approach To Complement 3D GCM Grid Simulations

by Keith CowingAugust 15, 2025August 15, 2025

With the development of ever-improving telescopes capable of observing exoplanet atmospheres in greater detail and number, there is a growing demand for enhanced 3D climate models to support and help […]

The colour-magnitude diagram of the CPM companion stars to host stars of confirmed exoplanets (left) and TOI PCs (right), corrected for G band extinction. The background consists of the primary and secondary stars in the El-Badry et al. (2021) binary catalog. The companion sources below the main sequence are discussed in Section 6.1. -- astro-ph.EP

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

A High Stellar Multiplicity Rate Amongst TESS Planet Candidates In The Neptunian Desert Using Gaia DR3 Astrometry

by Keith CowingJuly 1, 2025July 1, 2025

We aim to discover whether the stellar multiplicity rate may provide information on the origin of recently discovered planets in the Neptunian Desert.

Mass-Radius plot of asteroids, moons, planets, brown dwarfs and low-mass stars. From nearly 5600 exoplanets listed in the PHL-HWC database, 1504 are categorized as terrestrial worlds (orange dots), 2609 as Neptunian worlds (green dots), 1355 as Jovian worlds (purple dots), and 115 as brown dwarfs (brown dots). -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Brown Dwarfs, Exoplanets, -moons, -comets, Gas Giants, Ice Giant, Nomenclature, Systematics, Natural History, Status Report

(Re)-Defining Planets — the Fundamental Plane of Planets

by Keith CowingJune 23, 2025June 23, 2025

6000+ exoplanets are now detected using various techniques, with estimates of billions of planets existing in our Galaxy alone.

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

Re-analysis of 10 Hot-Jupiter Atmospheres With Disequilibrium Chemistry Retrieval

by Keith CowingJune 20, 2025June 20, 2025

Constraining the chemical structure of exoplanetary atmospheres is pivotal for interpreting spectroscopic data and understanding planetary evolution.

Transit depth versus wavelength for our full atmosphere model of HD209458b (Model C). We zoom in past the extent of the Hα and He I 10830 ˚A line to show the comparison with HST observations (Sing et al. 2016) and JWST observations (with different data reduction pipelines in different colors) (Xue et al. 2024). The JWST observations analyzed can be accessed via DOI:10.17909/f5j3-jq48. Note that the Na D and K I lines are a result of only the lower/middle atmosphere model, and we do not calculate transit depths for these lines based on the upper atmosphere model. -- astro-ph.EP

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

A Multi-Species Atmospheric Escape Model with Excited Hydrogen and Helium: Application to HD209458b

by Keith CowingJune 13, 2025June 12, 2025

Atmospheric escape shapes exoplanet evolution and star-planet interactions, with He I 10830 Å absorption serving as a key tracer of mass loss in hot gas giants. However, transit depths vary […]

Upper panel: the reduced IGRINS observation of WASP-77Ab. The flux at each phase is calibrated to the same level. The emission signal of WASP-77Ab is buried under the background and noise. Lower panel: Residual after removing the first 4 principal components. The residual should be a good representation of the signal. -- astro-ph.EP

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

Open Source High-Resolution Exoplanet Atmosphere Retrievals with POSEIDON

by Keith CowingMay 19, 2025May 19, 2025

High-resolution spectroscopy (R > 25,000) has opened new opportunities to characterize exoplanet atmospheres from the ground.

Contribution function for the evening and morning limb spectrum. (A) shows the contribution function as a function of pressure and wavelength from the best-fit 1.5D retrieval model for the evening limb. The contribution function is derived from the derivative of the transmittance with pressure for each wavelength value. (B) shows the contribution function for the morning limb spectrum. -- astro-ph.EP

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

Cloudy Mornings And Clear Evenings On Giant Extrasolar World WASP-94A b

by Keith CowingMay 19, 2025May 19, 2025

Aerosols are common in exoplanet atmospheres, but their formation-whether through gas condensation or photochemical reactions-remains uncertain.

Overview of the chemical elements detected in the transmission spectra of Ultra-Hot Jupiters (UHJ). Planets are ordered by decreasing equilibrium temperature. WASP-33 b is a more challenging target due to the presence of significant stellar pulsations. References: Borsa et al. (2021); Borsato et al. (2023); Hoeijmakers et al. (2018a, 2019, 2020, 2022); Yan & Henning (2018); Cauley et al. (2021); Yan et al. (2019); Prinoth et al. (2024); Prinoth et al. (2023); Stangret et al. (2020, 2022);Bello-Arufe et al. (2022, 2023); Azevedo Silva et al. (2022); Ben-Yami et al. (2020); Merritt et al. (2021); Maguire et al. (2023); Gandhi et al. (2023b); Jiang et al. (2023); Zhang et al. (2022); Casasayas-Barris et al. (2019); Fossati et al. (2023); Nugroho et al. (2020b); Ehrenreich et al. (2020); Tabernero et al. (2021); Deibert et al. (2021); Pelletier et al. (2023). -- astro-ph.EP

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

Exoplanet Atmospheres At High Spectral Resolution

by Keith CowingMay 15, 2025May 15, 2025

High-resolution spectroscopy (HRS) has grown into one of the main techniques to characterise the atmospheres of extrasolar planets. High spectral resolving power allows for the efficient removal of telluric and […]