cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.xbtipf
title: The architecture of multi-planet systems as a tracer of their formation mechanisms

description: Exoplanets observed by the Kepler telescope exhibit a bi-modal, radius distribution, which is knownas the radius gap. We explore an origin of the radius gap, focusing on multi-planet systems. Oursimple theoretical argument predicts that type I planetary migration produces different configurationsof protoplanets with different masses and such different configurations can result in two distinguishable populations of small-sized multi-planet systems. We then perform an observational analysis toverify this prediction. In the analysis, multiple Kolmogorov–Smirnov tests are applied to the observedsystems, using the statistical measures that are devised to systematically characterize the propertiesof multi-planet systems. We find with 99.5% confidence that the observed, small-sized multi-planetsystems are divided into two distinct populations. The distinction likely originates from different spatial distributions of protoplanets, which are determined by type I migration and subsequently triggergiant impact. We also show that these distinct populations are separated around the radius gap whenthe gas surface density of protoplanetary disks is ∼ 102 g cm−2in the vicinity of the host stars. Thiswork therefore emphasizes the importance of planetary migration and the inner disk properties.
DOI: 10.48577/jpl.ebug6z
title: Towards Wind Vector and Wave Height Retrievals Over Inland Waters Using CYGNSS

description: GNSS Reflectometry (GNSS-R) measurements over inland water bodies, such as lakes, rivers, and wetlands exhibit strong coherent signals. The strength of the coherent reflections is highly sensitive to small-scale surface roughness. For inland waters, this roughness is primarily due to wind-driven surface waves. The sensitivity of the coherent reflections to surface roughness can be leveraged to estimate wave height profiles across inland waters. Coupled with a wind wave model, an approach to retrieve wind vector is described using a forward model which is potentially able to predict scattered power profiles for different wind speeds and directions and choosing the minimum-squared error solution. The ability for spaceborne or airborne GNSS-R to measure inland water wind vector and wave heights could contribute to scientific applications focused on understanding nearshore ecosystems, monitoring climate change effects on inland waters, sediment resuspension, biomass production, fish habitat, and others. This paper presents a novel approach to potentially retrieve wind vector and wave heights over inland waters using GNSS-R and discusses the issues with performing such retrievals using simulation and very few available raw signals recorded from CYGNSS satellites.
DOI: 10.48577/jpl.gtcvwd
title: Global Reach-level 3-hourly River Flood Reanalysis (1980-2019)

description: Better understanding and quantification of river floods for very local and flashy events calls for modeling capability at fine spatial and temporal scales. However, long-term discharge records with a global coverage suitable for extreme events analysis are still lacking. Here, grounded on recent breakthroughs in global runoff hydrology, river modeling, high resolution hydrography, and climate reanalysis, we developed a 3-hourly river discharge record globally for 2.94 million river reaches during the 40-year period of 1980-2019. The underlying modeling chain consists of the VIC land surface model (0.05°, 3-hourly) that is well calibrated and bias corrected and the RAPID routing model (2.94 million river and catchment vectors), with precipitation input from MSWEP and other meteorological fields downscaled from ERA5. Flood events (above 2-year return) and their characteristics (number, spatial distribution, and seasonality) were extracted and studied. Validations against 3-hourly flow records from 6,000+ gauges in CONUS and daily records from 14,000+ gauges globally show good modeling performance across all flow ranges, good skills in reconstructing flood events (high extremes), and the benefit of (and need for) sub-daily modeling. This data record, referred as Global Reach-level Flood Reanalysis (GRFR), is publicly available at https://www.reachhydro.org/home/records/grfr.
DOI: 10.48577/jpl.hm2iob
title: Demonstration of a Consistent Relationship Between Dual-Frequency Reflectivity and the Mass-Weighted Mean Diameter in Measurements of Frozen Precipitation from GCPEX, OLYMPEX, and MC3E

description: The retrieval of the mass-weighted mean diameter (Dm) is a fundamental component of spaceborne precipitation retrievals. The Dual-Frequency Precipitation Radar (DPR) on the Global Precipitation Measurement (GPM) satellite is the first satellite to use Dual Wavelength Ratio measurements - the quotient of radar reflectivity factors (Z) measured at Ku and Ka wavelengths – to retrieve Dm. While it is established that DWR, being theoretically insensitive to changes in ice crystal mass and concentration, can provide a superior retrieval of Dm compared to Z based retrievals, the benefits of this retrieval have yet to be directly observed or quantified. In this study, DWR-Dm and Z-Dm relationships are empirically generated from collocated airborne radar and in-situ¬ cloud particle probe measurements. Data is collected during nine intensive observation periods (IOPs) from three experiments representing different locations and times of year. Across IOPs with varying ice crystal concentrations, cloud temperatures, and storm types, Z-Dm relationships vary considerably while the DWR-Dm relationship remains consistent. This study confirms that a DWR-Dm relationship can provide a more accurate and consistent Dm retrieval than a Z-Dm relationship, quantified by a reduced overall RMSE (0.19 mm and 0.25 mm, respectively)
DOI: 10.48577/jpl.plve0b
title: Heat and freshwater changes in the Indian Ocean region

description: Across the Indo-Pacific region, rapid increases in surface temperatures, ocean heat content and concomitant hydrological changes have implications for sea level rise, ocean circulation and regional freshwater availability . In this Review, we synthesise evidence from multiple data sources to elucidate whether the observed heat and freshwater changes in the Indian Ocean represent an intensification of the hydrological cycle, as expected in a warming world. At the basin scale, 20th century warming trends can be unequivocally attributed to human-induced climate change. Changes since 1980, however, appear dominated by multi-decadal variability associated with the Interdecadal Pacific Oscillation, manifested as shifts in the Walker circulation and a corresponding reorganisation of the Indo-Pacific heat and freshwater balance. Such variability, coupled with regional-scale trends, a short observational record and climate model uncertainties, make it difficult to assess whether contemporary changes represent an anthropogenically-forced transformation of the hydrological cycle. Future work must therefore focus on maintaining and expanding observing systems of remotely sensed and in situ observations, as well as extending and integrating coral proxy networks. Furthermore, improved climate model simulations of the Maritime Continent region and its intricate exchange between the Pacific and Indian Ocean are necessary to quantify and attribute Indo-Pacific heat and freshwater changes.
DOI: 10.48577/jpl.yncnuc
title: Genomic characterization of plant-growth promoting features of Sphingomonas strains isolated from the International Space Station, with an emphasis on phytohormone production

description: AbstractIn an ongoing microbial tracking investigation of the International Space Station (ISS), several Sphingomonas strains were isolated. Phylogenetic analysis, based on the 16S rRNA gene sequence, identified the ISS strains as S. sanguinis (n=2) and one strain isolated from the Kennedy Space Center cleanroom (used to assemble various Mars mission spacecraft components) as S. paucimobilis. Metagenomic sequence analyses of various ISS locations identified 23 Sphingomonas species, with an abundance of shotgun metagenomic reads detected for S. sanguinis in the location from where the ISS isolates were sampled. A complete genome was assembled from the metagenome and its comparison with the whole genome sequences (WGS) of the ISS isolates revealed that they were highly similar to S. sanguinis. In addition to the phylogeny, the WGS of these Sphingomonas strains were compared with WGS of the type strains to elucidate genes that can potentially aid in plant growth promotion. Furthermore, the WGS comparison of these strains with the well characterized Sphingomonas sp. LK11, a desert arid strain, identified several genes responsible for the production of phytohormones and for stress tolerance. Production of one of the phytohormones, Indole 3-acetic acid, was further confirmed in the ISS strains using metabolomics. Pathways associated with phosphate uptake, metabolism, and solubilization in soil were conserved across all the S. sanguinis and S. paucimobilis strains tested. Furthermore, genes thought to promote plant resistance to abiotic stress, including heat/cold shock response, heavy metal resistance, oxidative and osmotic stress resistance, appear to be present in these space related S. sanguinis and S. paucimobilis strains. Characterization of these biotechnologically important microorganisms found on the ISS and harnessing their key features will aid in the development of self-sustainable long-term space missions in the future.ImportanceSphingomonas is ubiquitous in nature, including the anthropogenically contaminated extreme environments. Members of the Sphingomonas genus have been identified as potential candidates for space biomining beyond earth. This study describes the isolation and identification of Sphingomonas members from the International Space Station, which are capable of producing the phytohormone indole 3-acetic acid. Microbial production of phytohormones will help future in situ studies, grow plants beyond low earth orbit, and establish self-sustainable life support systems. Beyond phytohormone production, stable genomic elements of abiotic stress resistance, heavy metal resistance, oxidative and osmotic stress resistance were identified, rendering the ISS Sphingomonas isolate a strong candidate for biotechnology -related applications.
DOI: 10.48577/jpl.bxujyt
title: A perturbation method for evaluating the magnetic field induced 1 from an arbitrary, asymmetric ocean world analytically

description: ble confirming the presence of subsurface, liquid water oceans. In the exploration of ocean 14 moons, especially Europa, there is a need formathematicalmodels capable of predicting themag- 15 netic fields induced under a variety of conditions, including in the case of asymmetric oceans. 16 Existing models are limited to either spherical symmetry or assume an ocean with infinite con- 17 ductivity. In this work, we use a perturbation method to derive a semi-analytic result capable of 18 determining the induced magnetic moments for an arbitrary layered body, provided each layer 19 is nearly spherical. Crucially, we find that degree-2 tidal deformation results in changes to the 20 induced dipolemoments. We demonstrate application of our results tomodels of plausible asym- 21 metry from the literature within the oceans of Europa and Miranda and the ionospheres of Cal- 22 listo and Triton. For the models we consider, we find that in the asymmetric case, the induced 23 magnetic field differs by more than 2 nT near the surface of Europa, 0:25–0:5 nT at 1R above 24 Miranda and Triton, and is essentially unchanged for Callisto. For Miranda and Triton, this dif- 25 ference is as much as 20–30% of the induced field magnitude. If measurements near the moons 26 can be made precisely to better than a few tenths of a nT, these values may be used by future 27 spacecraft investigations to characterize asymmetry within the interior of icy moons.
DOI: 10.48577/jpl.mvltyd
title: Draft Genome Sequences of Heat-Shock Tolerant Microbes Isolated from a Spacecraft Assembly Facility

description: Heat-shock tolerant microorganisms belonging to Bacillales and Micrococcales were isolated from the Spacecraft Assembly Facility at the Jet Propulsion Laboratory, and 63 draft genome sequences were assembled and identified. Further analyses of these genomes can provide insight into methods for preventing forward contamination.
DOI: 10.48577/jpl.wan57t
title: Re ected spectroscopy of small exoplanets I: determining the atmospheric composition of sub-Neptunes planets

description: Direct imaging of widely separated exoplanets from space will obtain their reected light spectra and7 measure their atmospheric properties, and small and temperate planets will be the focus of the next8 generation telescopes. In this work, we used our Bayesian retrieval algorithm ExoReL&lt; to determine9 the constraints on the atmospheric properties of sub-Neptune planets from observations taken with a10 HabEx-like telescope. Small and temperate planets may have a non-H2-dominated atmosphere, and11 therefore, we introduced the compositional analysis technique in our framework to explore the bulk12 atmospheric chemistry composition without any prior knowledge about it. We have developed a novel13 set of prior functions for the compositional analysis free parameters. We compared the performances of14 the framework with the at prior and the novel prior and we reported a better performance when using15 the novel priors set. We found that the retrieval algorithm can not only identify the dominant gas of16 the atmosphere but also to constrain other less abundant gases with high statistical condence without17 any prior information on the composition. The results presented here demonstrates that reected light18 spectroscopy can characterize small exoplanets with diverse atmospheric composition. The Bayesian19 framework should be applied to design the instrument and the observation plan of exoplanet direct20 imaging experiments in the future.
DOI: 10.48577/jpl.wfdfe2
title: Microstructure, mechanical properties, and ionic conductivity of a solid-state electrolyte prepared using binderless laser powder bed fusion

description: Manipulating the microstructure of the glass-ceramic solid-state electrolyte, Li1+xAlxTi2-x(PO4)3 (LATP), improves performance by enhancing ionic conductivity; however, conventional glass-ceramic processing requires multiple processing steps to successfully develop the microstructure. Laser-based additive manufacturing techniques, such as laser powder bed fusion (L-PBF), offer a novel approach to single-step fabrication of glass-ceramics for battery applications. We investigate the influence of the L-PBF processing on the microstructure, mechanical properties, and ionic conductivity of the lithium-ion battery solid-state electrolyte LATP. This study demonstrates that binderless L-PBF produces relatively dense LATP samples with the desired rhombohedral crystal structure and mechanical properties consistent with conventional LATP. We find that laser scan speed influences the development of secondary phase particles, which affect the ionic conductivity. Further parameter optimization will improve the ionic conductivity of L-PBF LATP to enable single-step fabrication of battery components using binderless laser-based additive manufacturing.
DOI: 10.48577/jpl.go4wox
title: Probing protoplanetary disk evolution in the Chamaeleon II region

description: Context. Characterizing the evolution of protoplanetary disks is necessary to improve our understanding of planet formation. Constraints on both dust and gas are needed todetermine the dominant disk dissipation mechanisms. Aims. We aim to compare the disk dust masses in the Chamaeleon II (Cha II) star-forming region with other regions with ages between 1 and 10 Myr. Methods. We use ALMA band 6 observations (1.3 mm) to survey 29 protoplanetary disks in Cha II. Dust mass estimates are derived from the continuum data. Results. Out of our initial sample of 29 disks, we detect 22 sources in the continuum, 10 in 12CO, 3 in 13CO, and none in C18O (J=2-1). Additionally, we detect two companion candidates in the continuum and 12CO emission. Most disk dust masses are lower than 10 M_Earth assuming thermal emission from optically thin dust. Including non-detections, we derive a median dust mass of 4.5 +/- 1.5 Mdust from survival analysis. We compare consistent estimations of the distributions of the disk dust mass and the disk-to-stellar-mass ratios in Cha II with six other low mass and isolated star-forming regions in the age range of 1-10 Myr: Upper Sco, CrA, IC 348, Cha I, Lupus, and Taurus. When comparing the dust to stellar mass ratio, we find that the masses of disks in Cha II are statistically different from those in Upper Sco and Taurus, and we confirm that disks in Upper Sco, the oldest region of the sample, are statistically less massive than in all other regions. Performing a second statistical test of the dust mass distributions from similar mass bins, we find no statistical differences between these regions and Cha II. Conclusions. We interpret these trends, most simply, as a sign of decline of the disk dust masses with time or dust evolution. Different global initial conditions in star-forming regions may also play a role, but their impact on the properties of a disk population is difficult to isolate in star-forming regions lacking nearby massive stars.
DOI: 10.48577/jpl.xfryni
title: New Constraints on Pluto's Sputnik Planitia Ice Sheet from a Coupled Reorientation-Climate Model

description: We present a coupled reorientation and climate model, to understand how true polar wander (TPW) and atmospheric condensation worked together to create the Sputnik Planitia (SP) glacier and reorient it to its present-day location on Pluto. SP is located at 18◦N, 178◦E, very close to the anti-Charon point, and it has been previously shown that this location can be explained by TPW reorientation of an impact basin as it fills with N2 ice. We readdress that hypothesis while including a more accurate treatment of Pluto’s climate and orbital obliquity cycle. Our model again finds that TPW is a viable mechanism for the formation and present-day location of SP. We find that the initial impact basin could have been located north of the present-day location, at latitudes between 35◦N and 50◦N. The empty basin is constrained to be 2.5 – 3 km deep, with enough N2 available to form at most a 1 – 2 km glacier. Larger N2 inventories reorient too close to the anti-Charon point. After reaching the final location, the glacier undergoes short periods of sublimation and re-condensation on the order of ten meters of ice, due Pluto’s variable obliquity cycle, which drives short periods of reorientation of a few km. The obliquity cycle also has a role in the onset of glacial infilling; some initial basin locations are only able to begin accumulating N2 ice at certain points during the obliquity cycle. We also explore the sensitivity of the coupled model to albedo, initial obliquity, and Pluto’s orbit.
DOI: 10.48577/jpl.c2qrjr
title: The Transition from Diuse Molecular Gas to Molecular Cloud Material in Taurus

description: We study four lines of sight that probe the transition from diuse molecular gas tomolecular cloud material in Taurus. Measurements of atomic and molecular absorption are used to infer the distribution of species and the physical conditions in the material toward stars behind the Taurus Molecular Cloud. New high-resolution spectra at visible and near infrared wavelengths of interstellar Ca II, Ca I, K I, CH, CH+, C2, CN, and CO toward HD 28975 and HD 29647 are combined with data at visible wavelengths and published results on CO from ultraviolet measurements for HD 27778 and HD 30122. Gas densities and temperatures are inferred from analyses of C2, CN, and CO excitation and of the chemistry leading to CN. Our results for HD 29647 are noteworthy in that the CO column density is 1018 cm􀀀2 and that analysis of C2 and CO excitation reveals a temperature of 10 K and density about 1000 cm􀀀3, more like conditions found in dark molecular clouds. Similar results arise from our chemical analysis leading to CN through reactions involving the observed species CH, C2, and NH. Enhanced potassiumdepletion and a much reduced CH/H2 column density ratio also suggest the presence of a dark cloud. The directions toward HD 27778 and HD 30122 probe material typical of molecule-rich diuse clouds, which can be considered CO-dark gas, while the sight line toward HD 28975 represents an intermediate case. Maps of dust temperature help refine the description of the material along the four sight lines and provide an estimate of the distance between HD 29647 and a core in the Taurus Molecular Cloud. An Appendix provides results for the sight line toward HD 26571 based on available data; this star also probes diuse molecular gas.
DOI: 10.48577/jpl.equxj0
title: Avoiding the “Great Filter”: A Projected Timeframe for Human Expansion Off-World

description: A foundational model has been developed based on trends built from empirical data of space exploration and computing power through the first six plus decades of the Space Age which projects earliest possible launch dates for human-crewed missions from cis-lunar space to selected Solar System and interstellar destinations. The model uses computational power, expressed as transistors per microprocessor, as a key broadly limiting factor for deep space missions’ reach and complexity. The goal of this analysis is to provide a projected timeframe for humanity to become a multi-world species through off-world colonization, and in so doing all but guarantees the long-term survival of the human race from natural and human-caused calamities that could befall life on Earth. Beginning with the development and deployment of the first nuclear weapons near the end of World War II, humanity entered a ‘Window of Peril’ which will not be safely closed until robust off-world colonies become a reality. Our findings suggest the first human-crewed missions to land on Mars, selected Asteroid Belt objects, and selected moons of Jupiter and Saturn can occur before the end of the 21st century. Launches of human-crewed interstellar missions to exoplanet destinations within roughly 40 lightyears of the Solar System are seen as possible during the 23rd century and launch of intragalactic missions by the end of the 24th century. An aggressive and sustained space exploration program, which includes colonization, is thus seen as critical to the long-term survival of the human race.