spectrophotometry Archives - Astrobiology

SPHEREx Pre-Perihelion Mapping

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Status Report

SPHEREx Pre-Perihelion Mapping of H2O, CO2, and CO in Interstellar Object 3I/ATLAS

by Keith CowingDecember 9, 2025December 9, 2025

From 01- to 15-Aug-2025 UT, the SPHEREx spacecraft observed interstellar object 3I/ATLAS. Using R=40-130 spectrophotometry at λ=0.7-5μm, light curves, spectra, and imaging of 3I were obtained.

SPHEREx 3.0/4.26/4.7 μm H2O/CO2/CO gas coma from left to right respectively. The object is undetected in H2O and CO, with 2-pixel radius preliminary conservative upper limits of 0.45 and 0.99 mJy. By contrast, a bright CO2 coma with central PSF flux = 33mJy that extends out to at least 30-pixel (=348,000 km) was found. This observed minimum size for the CO2 coma corresponds to ~700,000-second mean lifetime at vgas = 0.48 km/sec. The reported photodissociation lifetime for CO2 at 1au is 135hrs = 486,000 seconds (Huebner+1992), which scales by 1/r2 to ~4,670,000 seconds at 3.2au. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Status Report

SPHEREx Discovery of Strong Water Ice Absorption and an Extended Carbon Dioxide Coma in 3I/ATLAS

by Keith CowingAugust 22, 2025September 18, 2025

In mid-August 2025, 0.75-5.0 micron SPHEREx imaging spectrophotometric and ancillary NASA-IRTF SpeX 0.7-2.5 micron low-resolution spectral observations of Interstellar Object 3I ATLAS were obtained.

Forward-modeling results based on the Exo-REM models that include disequilibrium chemistry and clouds, with the same format as Figure 4. -- astro-ph.EP

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

Disequilibrium Chemistry, Diabatic Thermal Structure, and Clouds in the Atmosphere of COCONUTS-2b

by Keith CowingOctober 18, 2024October 18, 2024

Located 10.888 pc from Earth, COCONUTS-2b is a planetary-mass companion to a young (150–800 Myr) M3 star, with a wide orbital separation (6471 au) and a low companion-to-host mass ratio […]

Normalized bands areas of parietin (FT-IR reflectance) during UV irradiation under N2 flux showed as color gradient, where dark yellow is band's area before irradiation (100 %), orange is 50 % of beginning band's area, red is 0 % of beginning band's area and yellow is 150 % of beginning band's area. Numeric values are referred to Tab. S1. -- Science Direct

Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Habitable Zones, Plant Biology, Radiation, Status Report

UV Photo-degradation of the Secondary Lichen Substance Parietin: A Multi-spectroscopic Analysis in Astrobiology Perspective

by Keith CowingMay 27, 2024May 27, 2024

The cortical anthraquinone yellow-orange pigment parietin is a secondary lichen substance providing UV-shielding properties that is produced by several lichen species. In our work, the secondary metabolite has been extracted […]

JWST NIRCam albedos of Proteus and Puck compared to the spectra of 2004 EW95 (Plutino) and 2007 VL305 (Neptune Trojan) from JWST Programs 2418 and 2550 respectively. Also shown are Voyager-derived visual geometric albedos, with the Puck albedo selected to be at the same phase angle as the JWST observations (see Figure 6 of Karkoschka (2001) and Table 2 of Karkoschka (2003)). The spectrophotometry for Proteus and Puck closely matches the shape and albedo for the selected objects, both of which have less red/neutral spectral slopes, and perihelia also near 30AU. Higher resolution spectra for Puck and Proteus are needed to reveal surface composition. -- astro-ph.EP

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Miranda, Neptune, Oberon, Status Report, Titania, Triton, Umbriel, Uranus

JWST Spectrophotometry of the Small Satellites of Uranus and Neptune

by Keith CowingApril 11, 2024April 11, 2024

We use 1.4-4.6 micron multi-band photometry of the small inner Uranian and Neptunian satellites obtained with the James Webb Space Telescope’s near-infrared imager NIRCam to characterize their surface compositions.