[astro-ph.EP] Free-Floating Planets (FFPs) are a distinct class of exoplanets that do not orbit stars but are nevertheless found to be very common. A variety of formation mechanisms have been […]
white dwarf
![Best-fitting spectrum and atmospheric properties of WD 1856 b. a. Spectral decomposition illustrating the model components required to explain WD 1856 b’s JWST transmission spectrum (FIREFLy reduction; orange circles with 1 σ error bars). The best-fitting model (black curve) contains absorption from multiple CH4 features (purple shading), H2 + He continuum absorption (dark grey shading), and tentative evidence of C2H6 near 3.4 µm (brown shading) and PH3 near 4.3 µm (orange shading). Aerosol continuum opacity (silver shading) blocks thermal emission from the deep atmosphere in windows between CH4 bands, obscuring the ‘negative spikes’ that would otherwise be observed near 0.7 µm, 2.9 µm, and longwards of 4.0 µm for a clear atmosphere. The best-fitting model without nightside thermal emission (blue dashed curve) cannot explain the significantly lower transit depths longwards of 3.5 µm. b. Retrieved atmospheric properties, planetary mass, and aerosol properties from WD 1856 b’s JWST transmission spectrum for the FIREFLy (orange histograms) and Juniper (green histograms) data reductions. The median (solid line) and 1 σ credible intervals for each parameter (dashed lines) are overlaid. c. Residuals between the data and best-fitting model. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Aerosols.png?resize=1200%2C719&ssl=1)
Posted inAtmospheres, Climate, Weather
Aerosols And Hydrocarbons In The Atmosphere Of A White Dwarf Planet
[astro-ph.EP] Most stars, including our Sun, will one day evolve into red giants and, subsequently, white dwarfs. Several planet candidates have recently been identified orbiting white dwarfs, demonstrating that planets […]
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
From Hubble to HWO: Bridging the Frontier of White Dwarf Exoplanet Science
White dwarf stars, the endpoint of stellar evolution for 97% of stars in our Milky Way, offer a unique and powerful window into the bulk elemental composition of rocky exoplanetary […]
![The best-fit PICASO retrieval temperature-pressure (TP) profile is plotted as a solid blue line with the temperature-pressure knots indicated in solid blue circles. The light blue shaded region indicates the 3σ confidence interval of the retrieved TP profiles. The tightly constrained TP profiles in the 1–10 bar range match with the peak of the 3–5 µmcontribution function plotted in the right panel. The retrieved TP profile based on MIRI-LRS 5–11.7 µmspectrum in Voyer et al. (2025) is plotted in solid purple along with the 3σ uncertainty plotted as light-purple shaded region. The condensation curves of H2O, Na2S, and KCl at solar metallicity are plotted with blue, orange, and green dashed lines respectively. For reference, the solid black line shows the TP profile of the best-fit Elf Owl grid model ([M/H] = -1, C/O = 1.5, log(g) = 3.23, log(Kzz) = 7, Teff= 350 K). Right panel: The contribution function map of the best-fit PICASO retrieval results shows that most of the 3–5 µmflux is emitted from 0.1–10 bar region. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/02/JWST-Spectral-Retrieval.png?resize=1200%2C719&ssl=1)
Posted inAstrochemistry, Astronomy & Telescopes, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Press Release
JWST Spectral Retrieval Of Cold Directly Imaged Planet WD0806 b And The First
WD0806 b is a rare exoplanet companion orbiting a white dwarf, currently with a projected orbital distance of 2500 au. The Spitzer mid-IR photometry suggests that the temperature is as […]
Posted inAstrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Press Release
Astrochemistry: Webb Reveals The Helix Nebula In Glistening Detail
One of the closest planetary nebulas to Earth, the Helix Nebula has become a favorite among astronomers using ground- and space-based telescopes to study the final moments of a dying […]
Posted inAstrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
The Future of Evolved Planetary Systems
Understanding the formation, evolution, and chemical diversity of exoplanets are now central areas of astrophysics research. White dwarfs provide a uniquely sensitive laboratory for studying the end stages of planetary-system […]
Posted inExoplanets, -moons, -comets, Habitable Zones, Status Report, Stellar Cartography
General Relativity Can Prevent a Runaway Greenhouse on Potentially Habitable Planets Orbiting White Dwarfs
Planets orbiting in the habitable zones of white dwarfs have recently been proposed as promising targets for biosignature searches.
Posted inAstrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Icy Worlds, Imaging & Spectroscopy, Status Report
Discovery Of An Icy And Nitrogen-rich Extrasolar Planetesimal
White dwarfs accreting planetary debris provide detailed insight into the bulk composition of rocky exo-planetesimals. However, only one Kuiper-Belt analogue has been identified in that way so far.
Posted inAstrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Icy Worlds, Status Report
Detecting Water Ice And Vapor Disks Originating From Icy Planetary Bodies Around White Dwarfs With Future PRIMA Observations
Observations of atmospheres of polluted white dwarfs provide insights into the elemental composition of accreted exoplanets and exo-asteroids.
Posted inAstronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Press Release, Stellar Cartography
Do White Dwarfs Sample Water-Rich Planetary Material?
Polluted white dwarfs offer a unique way to directly probe the compositions of exoplanetary bodies.