Spectroscopy Archives

Retrieved spectral feature amplitude, AH, compared to clear, cloudy, and hazy atmosphere models from Morley et al. (2015). For the clear and cloudy models, the dotted lines indicate a 100× Solar metallicity atmosphere, and the dot-dashed lines a 300× Solar atmosphere. All hazy models were calculated at 50× Solar metallicity, the dotted lines are 1% haze precursor conversion, and the dashed lines are 10%. The green open markers, shown for context, are the measured CH4-retrieved AH values for K2-18 b and TOI-270 d. The black open markers, shown for context, are the Kepler-51 planets, which are excluded from the trend analysis due to their exceptionally low densities, and GJ 1214 b, which was found to significantly bias the trend fit due to the extremely precise flatness of its spectrum. -- astro-ph.EP

Clouds and Clarity: Revisiting Atmospheric Feature Trends in Neptune-size Exoplanets

by Keith CowingOctober 13, 2023October 13, 2023

Over the last decade, precise exoplanet transmission spectroscopy has revealed the atmospheres of dozens of exoplanets, driven largely by observatories like the Hubble Space Telescope.

Example simulated SCALES L band observations of an HR 8799 analog, with three planets having effective temperatures between 900 K and 1100 K and radii of 1 RJ. Top panels show ADI-processed slices from a low-resolution L band mock observation of a system of exoplanets similar to HR 8799. The bottom panel shows the recovered spectra for the three injected planets (green, purple, blue lines) plotted over the injected spectra (grey lines). The vertical lines in the bottom panel indicate the wavelengths of the three images in the top panels. The simulated observations assumed one hour of total integration time spread over ∼ 80◦ of parallactic angle evolution. -- astro-ph.IM

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

The Slicer Combined With Array Of Lenslets For Exoplanet Spectroscopy (SCALES): Driving Science Cases And Expected Outcomes

by Keith CowingOctober 12, 2023October 12, 2023

The Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy (SCALES) is a 2−5 μm, high-contrast integral field spectrograph (IFS) currently being built for Keck Observatory.

RVs over time for the best model (1P(5 d-ecc) + dSHO-GP28 d) fitted to the HARPS (top) and CARMENES (bottom) RVs of GJ 724. The GP component of the model is plotted as the orange solid line. The black lines show the median of 10 000 samples from the posterior and the grey shaded areas denote the 68 %, 95 %, and 99 % confidence intervals, respectively. Instrumental RV offsets were subtracted from the measurements and the model, and the error bars include the jitter added in quadrature. The residuals after subtracting the median model are shown in the lower panel. -- astro-ph.EP

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

Planetary Companions Orbiting The M Dwarfs GJ 724 And GJ 3988. A CARMENES And IRD Collaboration

by Keith CowingOctober 10, 2023October 10, 2023

We report the discovery of two exoplanets around the M dwarfs GJ 724 and GJ 3988 using the radial velocity (RV) method. We obtained a total of 153 3.5 m […]

IRSF/SIRIUS three-color composite image of M17, with J-band data shown in blue, H-band data in green, and Ks-band data in red. Image credits: Jiang et al. (2002). Superimposed are telescope/instrument apertures from ISOCAM (pink), ISO-SWS (red), and Akari (purple) observations. The two JWST apertures are shown and labeled in black. The translucent colored patches mark Spitzer -IRS spectral map observations, where each patch represents one of four distinct emission zones identified through hierarchical clustering (see Boersma et al. 2018). -- astro-ph.GA

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Imaging & Spectroscopy, Status Report

JWST: Deuterated PAHs, PAH-nitriles, and PAH Overtone and Combination Bands I: Program Description and First Look

by Keith CowingOctober 10, 2023October 10, 2023

A first look is taken at the NIRSpec 1-5 μm observations from JWST program 1591 that targets 7 objects along the low-mass stellar life cycle with PAH emission.

Broadband light curves of the flare-affected transits of TRAPPIST-1b and f. The transit models are shown in orange, and the exponential fit to the integrations in both the transit and flare is shown in blue. The exponential fit is necessary to determine the shape of the transit light curve. As shown in the O-C diagrams at the bottom, we use an initial guess of c1 and c2 to fit the exponential, then subtract the exponential to obtain final values of c1 and c2. We note c1 and c2 represent the coefficients of the quadratic limb darkening equation. The first and third O-C diagrams are directly comparable and show the light curve with the final transit model removed. The middle O-C diagram shows an intermediate step in the determination of the TRAPPIST-1f transit model fit in which the initial guess on the transit model is subtracted prior to fitting and subtracting the exponential. The residuals of the middle panel therefore show the quality of the exponential fit. -- astro-ph.SR

Exoplanets, -moons, -comets, Habitable Zones, Radiation, Space Weather & Heliophysics, Status Report, TRAPPIST-1

Characterizing The Near-infrared Spectra Of Flares From TRAPPIST-1 During JWST Transit Spectroscopy Observations

by Keith CowingOctober 9, 2023October 9, 2023

We present the first analysis of JWST near-infrared spectroscopy of stellar flares from TRAPPIST-1 during transits of rocky exoplanets. Four flares were observed from 0.6–2.8 μm with NIRISS and 0.6–3.5 […]

Joint constraints on the H2/He abundance and the atmospheric pressure on TRAPPIST-1 b resulting from the sequential fit of the stellar contamination and planetary atmosphere. The color shading illustrates the posterior probability density, where darker colors correspond to higher probabilities. Contours indicate the 1σ, 2σ, and 3σ Bayesian credible regions. The displayed posterior probability is marginalized over the H2O, CH4, CO, CO2, NH3, and N2 abundances. Hydrogen-dominated scenarios with high-altitude clouds are at the top left corner of the plot and cloud-free, volatile-rich, high-mean-molecular-mass atmospheres are at the bottom right. Any hydrogen-rich atmospheres without high-altitude clouds, at the bottom left, are robustly ruled out. The second horizontal axis at the top shows the mean molecular mass representative for a pure H2/H2O atmosphere. -- University of Michigan

Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, TRAPPIST-1

JWST’s First Spectrum Of A TRAPPIST-1 Planet

by Keith CowingOctober 8, 2023October 8, 2023

In a solar system called TRAPPIST-1, 40 light years from the sun, seven Earth-sized planets revolve around a cold star.

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 […]

Best-fit system in each modeling scenario compared to the true TRAPPIST-1 system using only Filippazzo et al. (2015) priors. The symbol size corresponds to the planet size, and the color indicates albedo. Horizontal bars indicate the uncertainty on a planet’s semi-major axis. Each modeling scenario is labeled with the number of planets included, the computed evidence, and its significance against the best-fit model. We use transparency to demonstrate which models are ruled out by > 3σ confidence. The vertical dashed lines indicate the limits of our semi-major axis bounds. -- astro-ph.EP

Astronomy & Telescopes, Status Report, TRAPPIST-1

On the Effectiveness of the Planetary Infrared Excess (PIE) Technique to Retrieve the Parameters of Multiplanet Systems around M dwarfs: A Case Study on the TRAPPIST-1 System

by Keith CowingOctober 1, 2023October 1, 2023

The planetary infrared excess (PIE) technique has the potential to efficiently detect and characterize the thermal spectra of both transiting and non-transiting exoplanets. However, the technique has not been evaluated […]

The transmission spectrum atmospheric effective altitude is plotted against wavelength between 0.2 µm and 11 µm for the P19 PI (orange), P19 10% PAL (brown), P19 1% PAL (yellow), and P19 0.1% PAL (red) simulations, and the W21 PI (light blue), W21 10% PAL (blue), W21 1% PAL (lilac), and W21 0.1% PAL (grey) simulations. The non-tidally locked cases are excluded for clarity, but show little differences compared to the equivalent tidally locked case. The transit depth, in terms of contrast with respect to the star, is indicated on the right vertical axis in parts per million (ppm). The spectra are binned to a spectral resolving power of R = 250. Spectral features are indicated in grey. The wavelength range of the proposed Habitable Worlds Observatory (HWO; blue shaded region), and that of the JWST NIRSpec instrument (yellow shaded region), are shown. They overlap in the green shaded region. The wavelength range of the JWST MIRI instrument is indicated in the magenta shaded region. The wavelength spacing between 0.2 – 1 µm is changed between 1 – 11 µm in order to clearly show the UV and visible regions. The black bar represents the uncertainty that would be present on a measurement that has reached the noise floor of the instrument, where the noise floor is indicated as 5 ppm. Note this error bar is an estimate of the performance of the telescope and does not indicate a measurement. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

Degenerate Interpretations Of O3 Spectral Features In Exoplanet Atmosphere Observations Due To Stellar UV Uncertainties: A 3D Case Study With TRAPPIST-1e

by Keith CowingOctober 1, 2023October 1, 2023

TRAPPIST-1e is a potentially habitable terrestrial exoplanet orbiting an ultra-cool M Dwarf star and is a key target for observations with the James Webb Space Telescope (JWST). One-dimensional photochemical modelling […]

IFU images from one of the two PRISM grating observations of Sedna, Gonggong, and Quaoar, collapsed along the entire wavelength axis. For Sedna and Gonggong, the 7x7 pixel yellow box 6 denotes the spectral extraction region, while the 21x21 pixel red box marks the inner boundary of the background region. Quaoar lies in a dense field of background stars, and all pixels outside of the 5x5 pixel yellow extraction box were masked, except for the two designated background regions, marked in red, which are free from visible astronomical sources. -- astro-ph.EP

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

A Tale Of 3 Dwarf Planets: Ices And Organics On Sedna, Gonggong, And Quaoar From JWST Spectroscopy

by Keith CowingOctober 1, 2023October 1, 2023

We observed Sedna, Gonggong, and Quaoar with the NIRSpec instrument on the James Webb Space Telescope (JWST). All three bodies were observed in the low-resolution prism mode at wavelengths spanning […]

Spectroscopy

Clouds and Clarity: Revisiting Atmospheric Feature Trends in Neptune-size Exoplanets

The Slicer Combined With Array Of Lenslets For Exoplanet Spectroscopy (SCALES): Driving Science Cases And Expected Outcomes

Planetary Companions Orbiting The M Dwarfs GJ 724 And GJ 3988. A CARMENES And IRD Collaboration

JWST: Deuterated PAHs, PAH-nitriles, and PAH Overtone and Combination Bands I: Program Description and First Look

Characterizing The Near-infrared Spectra Of Flares From TRAPPIST-1 During JWST Transit Spectroscopy Observations

JWST’s First Spectrum Of A TRAPPIST-1 Planet

Methods For Incorporating Model Uncertainty Into Exoplanet Atmospheric Analysis

On the Effectiveness of the Planetary Infrared Excess (PIE) Technique to Retrieve the Parameters of Multiplanet Systems around M dwarfs: A Case Study on the TRAPPIST-1 System

Degenerate Interpretations Of O3 Spectral Features In Exoplanet Atmosphere Observations Due To Stellar UV Uncertainties: A 3D Case Study With TRAPPIST-1e

A Tale Of 3 Dwarf Planets: Ices And Organics On Sedna, Gonggong, And Quaoar From JWST Spectroscopy

Astrobiologist Dale Andersen’s Antarctic Field Report: Wheels Down In Cape Town

NASA Spaceline Current Awareness List #1,221 16 October 2026 (Space Life Science Research Results)

SwRI Staff Contribute To New Ideas About Origins Of Uranus And Neptune

A Voyage Into The Slow-motion World Of Earth’s Deep Seas

Rosalind Franklin Rover Stand-In Tackles A Tilted Descent