Spitzer Archives

Atmospheric and stellar retrieval results for HAT-P-18 b. Top: Retrieved model transmission spectra from our JWST/NIRISS spectra (black errors). For each of the three retrieval codes (Poseidon; purple, SCARLET; orange, and Aurora; blue), the median retrieved spectrum (solid lines) and 1 𝜎 confidence intervals (shaded contours) are shown. The most important model features required to explain HAT-P-18 b’s NIRISS transmission spectrum are annotated. All three codes adopt the one heterogeneity model for this comparison. Bottom: Posterior probability distributions corresponding to the retrieval model in the top panel. The top row shows retrieved atmospheric properties with constrained values, the middle row shows non-detected chemical species with abundance upper limits, and the bottom row shows the retrieved unocculted starspot properties. Each histogram is annotated with the retrieved median and ± 1 𝜎 confidence intervals from the Poseidon retrieval for reference (see Table 4 for the results from all three codes). -- astro-ph.SR

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

Near-Infrared Transmission Spectroscopy of HAT-P-18b with NIRISS: Disentangling Planetary and Stellar Features in the Era of JWST

by Keith CowingOctober 24, 2023October 24, 2023

The JWST Early Release Observations (ERO) included a NIRISS/SOSS (0.6-2.8μm) transit of the ∼850K Saturn-mass exoplanet HAT-P-18b. Initial analysis of these data reported detections of water, escaping helium, and haze.

Transmission spectrum of HD 209458b, observed with HST STIS (orange points), HST WFC3 (red points), and Spitzer (green points). Overplotted are median model spectra drawn from the posteriors of each of the six retrievals described in Section 3.2. All models are the same except for their treatment of clouds and hazes. Median forward models have been downsampled to a resolution R = 200 for clarity. PL+G refers to power-law haze + grey cloud models, and A&M refers to Ackerman & Marley cloud models. -- astro-ph.IM

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

Methods For Incorporating Model Uncertainty Into Exoplanet Atmospheric Analysis

by Keith CowingOctober 7, 2023October 7, 2023

A key goal of exoplanet spectroscopy is to measure atmospheric properties, such as abundances of chemical species, in order to connect them to our understanding of atmospheric physics and planet […]

Sketch of a typical disk around a T Tauri star. Thermo-chemical disk models suggest a layered molecular structure with OH and CO at the top, followed by H2O and CO2. HCN and C2H2 peak in abundance deeper in the disk. Theory and observations suggest the possibility of radial transport of icy grains which can affect the inner disk gas composition. The MIRI instrument on board the James Webb Space Telescope probes the inner (≲ 10 au) warm disk surface. -- astro-ph.EP

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The Chemical Inventory of the Inner Regions of Planet-forming Disks — The JWST/MINDS Program

by Keith CowingJuly 31, 2023July 31, 2023

The understanding of planet formation has changed recently, embracing the new idea of pebble accretion. This means that the influx of pebbles from the outer regions of planet-forming disks to […]

This artist's illustration shows a planet (dark silhouette) passing in front of the red dwarf star AU Microscopii. The planet is so close to the eruptive star a ferocious blast of stellar wind and blistering ultraviolet radiation is heating the planet's hydrogen atmosphere, causing it to escape into space. Four times Earth's diameter, the planet is slowly evaporating its atmosphere, which stretches out linearly along its orbital path. This process may eventually leave behind a rocky core. The illustration is based on measurements made by the Hubble Space Telescope. Credits: NASA, ESA, and Joseph Olmsted (STScI)

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Press Release, Space Weather & Heliophysics

A Young Super-Earth Orbiting Red Dwarf AU Microscopii Is Evaporating

by Keith CowingJuly 29, 2023July 29, 2023

A young planet whirling around a petulant red dwarf star is changing in unpredictable ways orbit-by-orbit. It is so close to its parent star that it experiences a consistent, torrential […]

The distribution of upper level energies Eu and Einstein-A coefficients (top left and right plots, with color-coding reflecting Eu values) across infrared wavelengths naturally traces radial temperature gradients in inner disks within and across the water snowline (bottom plot, where the spectrum is scaled to a distance of 130 pc). Adapted from Figure 1 in Blevins et al. (2016) and Figure 13 in Banzatti et al. (2023). The MIRI lines used in the analysis in Section 3 are marked with black circles. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Imaging & Spectroscopy, Status Report

JWST Reveals Excess Cool Water Near The Snowline In Compact Disks, Consistent With Pebble Drift

by Keith CowingJuly 11, 2023July 11, 2023

Previous analyses of mid-infrared water spectra from young protoplanetary disks observed with the Spitzer-IRS found an anti-correlation between water luminosity and the millimeter dust disk radius observed with ALMA.

Artistic composition of tryptophan molecules in the star-forming region IC 348 located in the constellation Perseus. CREDIT Gabriel Pérez Díaz (IAC)

Astrochemistry, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Imaging & Spectroscopy, Interstellar, Press Release

Tryptophan, An Amino Acid Essential For Life, Has Been Found In Interstellar Space

by Keith CowingJune 24, 2023

Tryptophan is one of the 20 amino acids considered essential for the formation of proteins, which are key macromolecules for the development of life on Earth. This amino acid has […]

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Imaging & Spectroscopy, Interstellar, Press Release

Evidence Of The Amino Acid Tryptophan Found In Space

by Keith CowingJune 20, 2023June 20, 2023

Using data from the Spitzer space observatory, Dr Susana Iglesias-Groth, a researcher from The Instituto de Astrofísica de Canarias (IAC), has found evidence for the existence of the amino acid […]

LP 791-18 d, shown here in an artist’s concept, is an Earth-size world about 90 light-years away. The gravitational tug from a more massive planet in the system, shown as a blue disk in the background, may result in internal heating and volcanic eruptions – as much as Jupiter’s moon Io, the most geologically active body in the solar system. Astronomers discovered and studied the planet using data from NASA’s Spitzer Space Telescope and TESS (Transiting Exoplanet Survey Satellite) along with many other observatories. Credits: NASA’s Goddard Space Flight Center/Chris Smith (KRBwyle)

Astrogeology, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

A Potentially Volcano-Covered Earth-Size World Discovered

by Keith CowingMay 17, 2023April 14, 2024

Astronomers have discovered an Earth-size exoplanet, or world beyond our solar system, that may be carpeted with volcanoes. Called LP 791-18 d, the planet could undergo volcanic outbursts as often […]

LP 791-18 d, illustrated here, is an Earth-size world about 86 light-years away. The gravitational tug from a more massive planet in the system, shown as a blue dot in the background, may result in internal heating and volcanic eruptions on this exoplanet – as much as Jupiter’s moon Io, the most geologically active body in the Solar System. CREDIT NASA’s Goddard Space Flight Center/Chris Smith (KRBwyle)

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Press Release

LP 791-18 d: A Terrestrial Exoplanet – With Volcanoes

by Keith CowingMay 17, 2023May 17, 2023

A large international team led by astronomers at the Trottier Institute for Research on Exoplanets at Université de Montréal (UdeM) today announced in the journal Nature the discovery of a […]

Artistic composition of a “soup” of prebiotic molecules around a protoplanetary disc. CREDIT Gabriel Pérez Díaz (IAC)

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Imaging & Spectroscopy, Press Release

Molecular Precursors To Life Discovered In The Perseus Cloud

by Keith CowingApril 4, 2023April 4, 2023

The scientists Susan Iglesias-Groth, of the Instituto de Astrofísica de Canarias (IAC) and Martina Marín-Dobrincicof the Polytechnic University of Cartagena have discovered the presence of numerous prebiotic molecules in the […]

Spitzer

Near-Infrared Transmission Spectroscopy of HAT-P-18b with NIRISS: Disentangling Planetary and Stellar Features in the Era of JWST

Methods For Incorporating Model Uncertainty Into Exoplanet Atmospheric Analysis

The Chemical Inventory of the Inner Regions of Planet-forming Disks — The JWST/MINDS Program

A Young Super-Earth Orbiting Red Dwarf AU Microscopii Is Evaporating

JWST Reveals Excess Cool Water Near The Snowline In Compact Disks, Consistent With Pebble Drift

Tryptophan, An Amino Acid Essential For Life, Has Been Found In Interstellar Space

Evidence Of The Amino Acid Tryptophan Found In Space

A Potentially Volcano-Covered Earth-Size World Discovered

LP 791-18 d: A Terrestrial Exoplanet – With Volcanoes

Molecular Precursors To Life Discovered In The Perseus Cloud

Relevance of the Avalon Assemblage as an Astrobiological Analog for Icy Ocean Worlds

The Climate and Potential Habitability of a Warm and Oxygenated Mars

Variable X-ray flux May Explain Variable Helium Escape From The Habitable-zone Exoplanet LHS 1140b

Spacetime Contactability in Galactic Civilization Networks: Contact Counts and Percolation

Surprisingly Enriched CO and CH4 in Halley-type Comet 13P/Olbers: Clues to Its Interstellar Heritage