adsabs/AstroCLIMB huggingface dataset:
Paper: Resolved Convection in Hydrogen-rich Atmospheres
Authors: Jacob T. Seeley, Robin D. Wordsworth
Figure caption: Several quantities from the VaryMu experiments at surface temperatures of 280 K (blue), 300 K (black), and 320 K (red). (Top panel) Near-surface specific humidity qs. The critical humidity threshold qcrit is also plotted with a gray dashed line for the 300 K case; the weak direct temperature dependence of qcrit (Equation (13)) is indicated by the two thin gray lines that plot this same quantity for 280 K and 300 K. (Middle panel) Near-surface (50 m ≤z≤250 m) lapse rate, with the dry-adiabatic lapse rate for background gas molar mass μa also shown as a reference. (Bottom panel) Magnitude of the low cloud fraction peak.
Paper: Resolved Convection in Hydrogen-rich Atmospheres
Authors: Jacob T. Seeley, Robin D. Wordsworth
Figure caption: Temperature profiles for atmospheres with a surface temperature of 300 K, surface pressure of 105 Pa, and with varying background gas molar mass μa. The left panel shows idealized moist adiabats, while the right panel shows the steady-state temperature profiles from our cloud-resolving simulations. The inset focuses on the lowermost 6 km of the CRM simulations.
Paper: Resolved Convection in Hydrogen-rich Atmospheres
Authors: Jacob T. Seeley, Robin D. Wordsworth
Figure caption: (Top panel) Column-integrated water vapor in the CRM simulations from the VaryMu experiment, in comparison to the same quantity calculated from idealized moist-adiabatic atmospheres with 50% relative humidity. (Bottom panel) Low (z≤5 km) cloud altitude (i.e., the altitude of the peak in cloud fraction below 5 km) and amount (i.e., the magnitude of the low cloud peak) in the VaryMu experiment.
Paper: A Complex Systems Approach to Exoplanet Atmospheric Chemistry: New Prospects for Ruling Out the Possibility of Alien Life As We Know It
Authors: Theresa Fisher, Estelle Janin, Sara Imari Walker
Figure caption: Conceptual representations, abundance profiles, and network visualizations for each category of Archean Earth atmospheric model used in this study. The first column shows schematics of the scenarios under study. The second column shows the vertical profiles of the atmospheric species abundances corresponding to the initial conditions for each scenario. All initial abundances are fixed, except for methane. The blue shaded window corresponds to the range of methane abundances of simulations of this scenario, the solid blue line corresponds to the average methane concentration for all the simulations, and the solid black line corresponds to the methane vertical profile for one example instance, randomly extracted from the simulation batch. For the network visualizations, the nodes are not labeled for clarity, but in the case of the first three scenarios, the three dominant edges connect the following nodes: NO, NO2, HO2, and SO2ii (in an excited state)—i.e., these are very reactive species in these atmospheres. From top to bottom, we show the following scenarios studied herein. (1) Abiotic flux from serpentinization. Methane is modeled with a known abiotic flux mechanism, sourced from the planetary surface as the product of serpentinization. (2) Biotic surface flux. Methane is modeled with a known biological surface flux mechanism like that expected to have been present on the Archean Earth, with methanogenesis reactions from Earth’s metabolisms explicitly included in the model. (3) Anomalous surface flux. Methane is modeled as the result of a surface flux of undetermined origin. Flux rates are set to be comparable to those of biotic production rates on Earth (biotic surface flux model). (4) Anomalous atmospheric steady state. Methane is modeled as a component of a steady-state atmosphere, with abundance levels comparable to those produced by biology on Earth (biotic surface flux model).
Paper: A Complex Systems Approach to Exoplanet Atmospheric Chemistry: New Prospects for Ruling Out the Possibility of Alien Life As We Know It
Authors: Theresa Fisher, Estelle Janin, Sara Imari Walker
Figure caption: Top: distributions of the probability (y-axis) of a simulated atmosphere yielding the given network metric value and variance in the distribution of species abundances or CH4 abundance in log ppm (x-axis) over each of the sampled Archean Earth data sets, probed at 0.2 mbar. Scenarios included are models where methane is modeled as an abiotic surface flux (brown); models where methane is modeled as a biotic surface flux with the methanogenesis pathway explicitly included in the CRN (green); models where methane was modeled as originating from a surface flux of undetermined origin, e.g., anomalous surface flux (purple); and models where methane is modeled as an anomalous steady-state component of the planet’s atmosphere with an unknown source (yellow). Bottom: Anderson scores of the biotic flux scenario as compared to the three control models (abiotic flux, anomalous surface flux, and anomalous steady state). Each bar indicates the performance of the corresponding metric in distinguishing between different modeled scenarios. The horizontal black dotted line indicates the critical value (6.546) beyond which scenarios can be distinguished at a 0.1% confidence level. The vertical blue dotted line separates CH4 concentration and species abundance variance from the network metrics.
Paper: A Complex Systems Approach to Exoplanet Atmospheric Chemistry: New Prospects for Ruling Out the Possibility of Alien Life As We Know It
Authors: Theresa Fisher, Estelle Janin, Sara Imari Walker
Figure caption: Bayesian analysis of the posterior likelihood of life, P(life|observation), assuming an observed value for network metrics, variance of species abundances, or methane gas abundance, probed at 0.2 mbar. Given that the probability for life to exist on an exoplanet is unknown, we assess the posterior likelihood over a range of prior probabilities for life, P(life). Gray regions highlight metric values that are associated with a zero probability of life and are therefore antibiosignatures for the sets of models compared herein. In general, the subset of network metrics studied here can provide greater constraints on the probability of life given a set of observations than CH4 abundance alone, allowing distinguishing cases where Earth-like methanogenesis can be ruled out even when CH4 abundance alone is not conclusive.
Paper: A Complex Systems Approach to Exoplanet Atmospheric Chemistry: New Prospects for Ruling Out the Possibility of Alien Life As We Know It
Authors: Theresa Fisher, Estelle Janin, Sara Imari Walker
Figure caption: Conceptual representations, abundance profiles, and network visualizations for each category of modern Earth atmospheric model used in this study. The first column shows the scenario, the second column shows the vertical profiles of the atmospheric species abundances corresponding to the initial conditions for each scenario, and the third column shows a network representation of the chemistry in the atmosphere. From top to bottom: (1) Baseline modern Earth model. This model includes no industrial CFC-12 emissions. (2) Modern Earth modeled with emissions of CFC-12. A technosphere is modeled by the addition of a technological source for chloride radicals that can catalyze the destruction of O3.
Paper: A Complex Systems Approach to Exoplanet Atmospheric Chemistry: New Prospects for Ruling Out the Possibility of Alien Life As We Know It
Authors: Theresa Fisher, Estelle Janin, Sara Imari Walker
Figure caption: Top: distributions of the probability (y-axis) for a simulated atmosphere to yield the given species abundance variance or network metric value (x-axis) for data sets sampled from modern Earth atmospheres with and without the presence of CFC-12. Bottom: Anderson scores quantifying the reliability of each network metric to distinguish between atmospheres with and without CFC-12, where the threshold for distinguishability is at 6.546 (0.1% significance level).
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: Comparison between select Callisto spectra and some laboratory spectra discussed in the text. The color and associated number for each Callisto spectrum correspond with the locations mapped in Figure 1(a), and the longitude and latitude are listed in panel (a). Examples of local continuum fits, indicated with black dashed lines, and corresponding continuum-removed features for the 230, 320, 450, 820, and 930 nm absorption features are shown in panels (b) and (c). The approximate positions of the band centers for the 230, 320, 450, 820, and 930 nm absorption bands are indicated with vertical dashed gray lines, and the position of the long-wavelength shoulder of the 275 nm absorption edge is indicated by the solid gray line. Individual laboratory spectra are shown and labeled in black. As discussed in detail in Section 5, the identification of specific minerals to explain each UV and visible absorption feature on Callisto is difficult, and identifications typically remain ambiguous. However, we can use some of the potential spectral matches, in combination with the spatial distributions of the features, to explore possible compositions. See Sections 5 and 6 for a detailed discussion. Laboratory spectra in panel (a) include the Na- and Ca-bearing carbonate shortite (PSF sample CRB126), the phyllosilicate chamosite (PSF sample CHM102), an intimate mixture of the orthopyroxene-rich Millbillillie eucrite meteorite and phyllosilicate-rich Murchison CM2 chondrite (E. Cloutis et al. 2013), the iron oxide goethite (USGS sample WS222), the sodium sulfate natrojarosite (PSF sample SPT108), the Fe–Mg orthopyroxene enstatite (En30; R. L. Klima et al. 2007), ferric ammonium sulfate (PSF sample SPT104), the iron sulfate fibroferrite (E. A. Cloutis et al. 2006), the phyllosilicate serpentinite (PSF sample SRP105), and laboratory tholins produced by irradiation of mixtures of H2O:CH3:CO2:C2H6 ices (ice tholin; G. D. McDonald et al. 1996) and N2:CH4 ices (Triton tholin; D. P. Cruikshank et al. 2005). Panel (b) includes the continuum-removed 450 nm feature from the serpentinite spectrum in panel (a), continuum-removed spectra of irradiated NaCl at Europa-like conditions (M. E. Brown et al. 2022), continuum-removed spectra of irradiated mixtures of H2O:NH4:CH3OH ices that are warmed to 120 K post irradiation (I. Wong et al. 2019), the Triton and ice tholins from panel (a), spectra of the liquid phase organics azobenzene, mesityl oxide, and ethyl acetate from NIST (V. Talrose et al. 2001), amorphous carbon (W. Duley 1984), and 0.16% H2O2 in water ice (R. W. Carlson et al. 1999b). Panel (c) includes continuum-removed spectra of chamosite, the Millbillillie eucrite and Murchison CM2 chondrite mixture, natrojarosite, orthopyroxene, ferric ammonium sulfate, and fibroferrite from panel (a), as well as a spectrum of the asteroid 368 Haidea from F. Vilas et al. (1994).
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: (a) Callisto’s 280 nm absorption shows up in leading hemisphere spectra when ratioed against the trailing hemisphere. Europa’s trailing/leading hemisphere ratio spectrum (blue) shows a clear 280 nm band, which matches the laboratory spectrum of irradiated SO2 ice that is warmed to 100 K (R. Ramachandran et al. 2023) and is typically attributed to SO2 created from Iogenic sulfur implantation (A. L. Lane et al. 1981; A. R. Hendrix et al. 2011; T. M. Becker et al. 2022). Ganymede’s trailing/leading hemisphere ratio spectrum (teal) shows a strong band centered at 260 nm attributed to radiolytically produced O3 (K. S. Noll et al. 1996; P. Boduch et al. 2016), which also clearly matches the laboratory spectrum of O3 in water ice from B. Teolis et al. (2006). The hemispherically averaged leading/trailing spectrum of Callisto (red) is compared with the observations of K. S. Noll et al. (1997), who originally attributed this band to SO2 on the leading hemisphere. Our HST observations clearly show that the band is broader than assumed by K. S. Noll et al. (1997) and is not necessarily an obvious match to SO2 or a combination of SO2, O3, and an unidentified band past 300 nm, as suggested by R. Ramachandran et al. (2023). Instead, as demonstrated in (b), the ratio spectrum can be explained by dividing a spectrum with a strong 320 nm feature, which maps predominantly to the leading hemisphere, by a spectrum with a strong 275 nm absorption edge that is constrained to the trailing hemisphere. The spectra of the two pixels that produce the deepest 280 nm ratio feature are plotted in blue and orange, and their ratio (orange/blue) is shown in yellow, clearly demonstrating that the ratio of the 320 nm band/275 nm edge produces an apparent 280 nm absorption. This means that an additional absorber, like SO2 or O3, is not required to explain the 280 nm ratio feature, and we do not find strong evidence for SO2 on Callisto’s leading hemisphere.
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: Maps showing Callisto’s bolometric albedo ((a); from M. Camarca et al. 2023) compared with the spectral slope from 360 to 410 nm (b), which measures the strength of the near-UV downturn (redder slope = stronger downturn). The per-pixel estimated 1σ error on the 360–410 nm slope ranged from ±4.9 × 10−5 to ±2.2 × 10−4, and the minimum (black) and maximum (gray) estimated error is shown on the color bar. On both maps, the large ringed basins Valhalla (56°W, 16°N), Asgard (140°W, 32°N), Utgard (134°W, 45°N), and Adlinda (36°W, 48°S) are outlined with black dashed lines. For Valhalla, Asgard, and Adlinda, the central, inner, and outer rings are shown, based on the geologic map from R. Greeley et al. (2000). A few young, bright impact features are also indicated in solid black, along with Heimdall (357°W, 65°S) and Lofn (22°W, 56°S) craters and their relatively extensive ejecta. The scatter plots (c), produced by degrading the spatial resolution of the albedo map to match the HST/STIS observations, reveal the moderate correlation between the bolometric albedo and near-UV downturn on Callisto’s leading and trailing hemispheres, and the Pearson correlation coefficient (R) is shown on each plot. The color bar indicates the NIR slope (700–1000 nm) mapped in Figure 3.
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: (a) Map showing the NIR spectral slope from 700 to 1000 nm. The per-pixel estimated 1σ error on the slope ranged from ±3.3 × 10−6 to ±1.5 × 10−5, and the minimum (black) and maximum (gray) estimated error is shown on the color bar. Most of the surface has a neutral or red NIR slope except for the regions at southern latitudes and near Heimdall and Lofn that show an abundance of icy material and the central zones of the Valhalla, Asgard, and Utgard ringed basins, which have slightly blue slopes. (b) Scatter plots demonstrating the moderate correlation between the albedo and NIR slope, especially on the leading hemisphere. Pixels with the reddest NIR slopes tend to be dark, but not all dark material is particularly red. A moderate correlation between NIR red and UV red material is seen in the dark material on the leading hemisphere, but such a relationship is not as apparent on the trailing hemisphere.
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: Maps showing our two proxies for the strength of the 275 nm absorption edge: (a) the normalized slope from 230 to 270 nm, and (b) the integrated band area (from 220 to 275 nm) after dividing by a base spectrum constructed from five pixels identified as having the weakest 275 nm absorption edge. The feature is constrained to the trailing hemisphere and is likely associated with the stronger irradiation environment, although the somewhat irregular distribution suggests that it may require radiolysis of an unevenly distributed endogenic species. (c) Scatter plots demonstrating that the 275 nm absorption edge is uncorrelated with the bolometric albedo. The estimated 1σ error for the calculated 230–270 nm slope and 220–275 nm band area of each spatial pixel ranges from ±8.0 × 10−5 to ±4.2 × 10−4 and ±0.14 to ±0.33 nm, respectively. The minimum (black) and maximum (gray) estimated error is shown on the color bars in panels (a) and (b).
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: Map showing the calculated band area of the combined 820 and 930 nm absorption features (a), along with scatter plots (b) demonstrating that there is no notable correlation between the relative albedo of the dark material and the strength of the 820 and 930 nm bands, and the very weak anticorrelation can largely be explained by the tendency for the highest-albedo pixels to have little to no sign of an 820 or 930 nm feature. Pixels with the strongest 820 and 930 nm absorptions tend to have fairly red NIR slopes, especially on the trailing hemisphere, where almost all of the NIR reddest pixels (700–1000 nm slope ⪆2 × 10−4) have a relatively strong combined band strength. The estimated 1σ error for the calculated band area of each spatial pixel ranges from ±0.06 to ±0.23 nm, and the minimum (black) and maximum (gray) estimated error is shown on the color bar in panel (a). The gray circles on the map indicate the locations of the spectra in Figure 4, which demonstrate the overlap between the 820 and 930 nm bands.
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: (a) Map showing the calculated band area of the 280 nm ratio feature for spectra ratioed with the center of the trailing hemisphere. Negative values represent pixels where the ratio spectrum is above the linear continuum, and there is no apparent 280 nm feature present. As expected, the band is strongest on the leading hemisphere and largely absent from the trailing hemisphere. (b), (c) Scatter plots demonstrating that the 280 nm ratio feature is strongly anticorrelated with the 275 nm absorption edge, especially on the trailing hemisphere, and strongly positively correlated with the 320 nm absorption band. We interpret the 280 nm ratio band to be a direct consequence of these two absorption bands, which map strongly to separate hemispheres, and find that additional absorbers on the leading hemisphere (like SO2) are not required to explain the spatial distribution of the ratio feature. The estimated 1σ error for the calculated band area of each spatial pixel ranges from ±0.13 to ±0.61 nm, and the minimum (black) and maximum (gray) estimated error is shown on the color bar in panel (a).
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: A selection of spectra showing regions on Callisto’s surface where there is a clear 820 nm absorption with little to no 930 nm absorption (1: (76°W, 20°N)), a clear 930 nm absorption with a relatively weaker 820 nm absorption (2: (312°W, 12°S)), and relatively strong 820 and 930 nm absorptions that appear to merge into a single broader feature (3: (145°W, 15°N)). The spectra have been divided by a linear continuum (horizontal dashed lines), smoothed with a five-pixel moving average filter, and offset for clarity. The 820 and 930 nm band centers are indicated by vertical dashed lines and a best-fit two Gaussian model is overplotted in red to help guide the eye. The location of each spectrum is indicated on the map in Figure 5(a).
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: (a) The map of the strength of the 320 nm absorption demonstrates that it is largely constrained to the regions within and surrounding the Asgard and Valhalla impact basins, which leads to clear hemispheric asymmetry. The scatter plots (b) reveal a moderately strong negative correlation with albedo, with the pixels displaying a significant 320 nm absorption, tending to be both dark and NIR red. The strongest measured 320 nm band areas are associated with dark and red material directly east of Valhalla, which is partially within the outer ring or trough zone. The estimated 1σ error for the calculated band area of each spatial pixel ranges from ±0.1 to ±0.27 nm, and the minimum (black) and maximum (gray) estimated error is shown on the color bar in panel (a).
Paper: Spectroscopic Mapping of Callisto with HST/STIS and Implications for its Surface Composition
Authors: M. Ryleigh Davis, Samantha K. Trumbo, Michael E. Brown, Mathew Belyakov
Figure caption: Comparison of HST/STIS UV (left) and visible (right) spectra of the leading and trailing hemispheres of Callisto, Ganymede, and Europa, and a patch of bright white (sulfur-rich) material on Io’s leading hemisphere. The leading and trailing averages for Europa, Ganymede, and Callisto include all UV and visible pixels within ∼53° of the leading and trailing points, respectively, combined to create a full 200–1000 nm spectrum. All spectra are normalized to 1000 nm and are offset for clarity (+0, +0.25, +0.3, +0.6, +0.75, +1, and +1.1).
Paper: Crater Dimensions on the Dwarf Planets
Authors: Veronica J. Bray, Michael F. Zeilnhofer, S. J. Robbins, P. M. Schenk, Kelsi M. Singer, O. L. White, S. A. Stern, S. D. Benecchi, K. A. Durfey, H. A. Weaver, C. B. Olkin, J. R. Spencer
Figure caption: (A) Rim-to-floor depth measurements from this work for the whole Charon and Pluto data sets (preservation states 1–6),for only the freshest craters of the Ceres data set of this work (Table 3) and from P. M. Schenk et al. (2021); Ganymede data from V. J. Bray et al. (2008, 2012b) are included for comparison. Trend lines are plotted using only craters with preservation states 3–6, and equations displayed in the key. The lower three plots show the rim-to-floor depths of the craters presented as open symbols, alongside already published data, shown as closed circles. (B) The same but for Ceres only. Open symbols show the freshest data from this work and P. M. Schenk (2021); the data cloud displays the range of all Ceres data presented in this work. Closed symbols present data from M. F. Zeilnhofer & N. G. Barlow (2021). (C) The same but for Charon only. Open symbols show the data from this work, closed symbols show data from S. J. Robbins et al. (2021). (D) The same but for Pluto only. Open symbols show the data for this work, closed symbols show data from S. J. Robbins et al. (2021). The possible overturn of the d/D trend is shown in C and D, with equations presented for comparison to the single trend shown in A.