A5055965349- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Planetary Science and Exploration
- High-pressure geophysics and materials
- Space Exploration and Technology
- Astrophysics and Star Formation Studies
- Geological and Geochemical Analysis
- Space Science and Extraterrestrial Life
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Geologic Mapping
- Crystal Structures and Properties
- Atmospheric Ozone and Climate
- Marine and coastal plant biology
- Geology and Paleoclimatology Research
- History and Developments in Astronomy
- Astrophysical Phenomena and Observations
- Isotope Analysis in Ecology
- Infrared Target Detection Methodologies
- Astronomical Observations and Instrumentation
- Marine and coastal ecosystems
- Methane Hydrates and Related Phenomena
- Metallurgy and Cultural Artifacts
Southwest Research Institute
2021-2024
Arizona State University
2017-2021
The Ohio State University
2007-2016
We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hβ lag measurements for several relatively low-luminosity active galactic nuclei (AGNs). have reliably measured time delay between variations in continuum and emission line six local Seyfert 1 galaxies. These are used calculate mass of supermassive black hole at center each these AGNs. place our context most current calibration...
A detailed analysis of the data from a high sampling rate, multi-month reverberation mapping campaign, undertaken primarily at MDM Observatory with supporting observations telescopes around world, reveals that Hbeta emission region within broad line regions (BLRs) several nearby AGNs exhibit variety kinematic behaviors. While primary goal this campaign was to obtain either new or improved lag measurements for relatively low luminosity (presented in separate work), we were also able...
We present BurnMan, an open-source mineral physics toolbox to determine elastic properties for specified compositions in the lower mantle by solving Equation of State (EoS). The toolbox, written Python, can be used evaluate seismic velocities new data or geodynamic models, and as forward model inversions composition. user define composition from a list minerals provided easily include their own. BurnMan provides choices methodology, both EoS multiphase averaging scheme. results visually...
Abstract The two primary observable quantities of an exoplanet—its mass and radius—alone are not sufficient to probe a rocky exoplanet’s interior composition mineralogy. To overcome this, host-star abundances the planet-building elements (Mg, Si, Fe) typically used as proxy for planet’s bulk composition. majority small exoplanet hosts, however, do have available abundance data. Here we present open-source ExoPlex mass–radius–composition solver. Unlike previous mass–radius solvers, calculates...
We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations telescopes around world. The primary goal of this was to obtain either new or improved Hβ lag measurements for several relatively low luminosity active galactic nuclei (AGNs). feature NGC 4051 here because, until now, object has been significant outlier AGN scaling relationships, e.g., it previously ∼2–3σ on relationship...
The compositions of stars and planets are connected, yet, the definition "habitability" "habitable zone" only take into account physical relationship between star planet. Planets, however, made truly habitable by both chemical processes which regulate climatic geochemical cycling atmosphere, surface, interior reservoirs. Despite this, "Earth-like" is often defined as a planet mixture rock Fe that roughly 1 Earth-density. To understand terrestrial planet, stellar abundances planet-building...
Solar photospheric abundances of refractory elements mirror the Earth's to within ~10 mol% when normalized dominant terrestrial planet-forming Mg, Si and Fe. This allows for adoption composition as an order-of-magnitude proxy Earth's. It is not known, however, degree which this mirroring stellar planet holds true other star-planet systems without determination initial planetesimals via condensation sequence calculations post processes. We present open-source Arbitrary Composition...
We present the first investigation of Th abundances in solar twins and analogues to understand possible range this radioactive element its effect on rocky planet interior dynamics potential habitability. The elements U are key components a planet's energy budget, making up 30%–50% Earth's. Radiogenic heat drives mantle convection surface plate tectonics, which sustains deep carbon water cycle thereby aides creating Earth's habitable surface. Unlike other sources that dependent specific...
The interior composition of exoplanets is not observable, limiting our direct knowledge their structure, composition, and dynamics. Recently described observational trends suggest that rocky exoplanets, is, planets without significant volatile envelopes, are likely limited to $
Abstract The bulk density of a planet, as measured by mass and radius, is result planet structure composition. Relative proportions iron core, rocky mantle, gaseous envelopes are degenerate for given density. This degeneracy reduced planets without significant when the assumed to be differentiated core in which fraction (CMF) first-order description planet’s A CMF may derived both from assuming reflects host star’s major rock-building elemental abundances (Fe, Mg, Si). Contrasting measures,...
Understanding the physical characteristics of Venus, including its atmosphere, interior, and evolutionary pathway with respect to Earth, remains a vital component for terrestrial planet evolution models emergence and/or decline planetary habitability. A statistical strategy evaluating pathways planets lies in atmospheric characterization exoplanets, where sample size provides sufficient means determining required runaway greenhouse conditions. Observations potential exoVenuses can help...
ABSTRACT An exoplanet’s structure and composition are first-order controls of the planet’s habitability. We explore which aspects bulk terrestrial planet interior affect chief observables an exoplanet: its mass radius. apply these perturbations to Earth, we know best. Using mineral physics toolkit BurnMan self-consistently calculate mass–radius models, find that core radius, presence light elements in core, upper mantle consisting low-pressure silicates have largest effects on final...
The ideal exoplanets to search for life are those within a star's habitable zone. However, even the zone planets can still develop uninhabitable climate states. Sustaining temperate over geologic ($\sim$Gyr) timescales requires planet contain sufficient internal energy power planetary-scale carbon cycle. A major component of rocky planet's budget is heat produced by decay radioactive elements, especially $^{40}$K, $^{232}$Th, $^{235}$U and $^{238}$U. As ages these elements decay, this...
We analyze the r-band absolute magnitude and u − r color of low-redshift (z < 0.06) galaxies in Sloan Digital Sky Survey Data Release 6. Galaxies with nearly exponential profiles (Sloan parameter fracDeV 0.1) fall on blue sequence color-magnitude diagram; if, addition, these have Mr≲ 19, they show a dependence apparent axis ratio q expected for dusty disk galaxy. create subsample bright galaxies, typical Hubble types Sbc Sc; then, by comparing normalized luminosity functions different values...
Many branches of physics, chemistry and Earth sciences build complex materials from simpler constructs: rocks are composites made up one or more phases; phases solutions than endmember; endmembers usually mixtures element.The properties the endmember building blocks at different pressures temperatures can be modelled using a wide array equations state.There also many models for averaging within composite materials.Once calculated, physical used in ways.BurnMan is an open source, extensible...
The current goals of the astrobiology community are focused on developing a framework for detection biosignatures, or evidence thereof, objects inside and outside our solar system. A fundamental aspect understanding limits habitable environments (surface liquid water) detectable signatures thereof is study where boundaries such can occur. Such studies provide basis how once inhabitable planet might come to be uninhabitable. archetype arguably Earth's sibling planet, Venus. Given need define...
Abstract Exoplanet discoveries have reached into the realm of terrestrial planets that are becoming subject atmospheric studies. One such discovery is LHS 3844b, a 1.3 Earth radius planet in 0.46 day orbit around an M4.5-5 dwarf star. Follow-up observations indicate largely devoid substantial atmosphere. This lack significant atmosphere places astrophysical and geophysical constraints on primarily degree volatile outgassing rate erosion. We estimate age host star as 7.8 ± 1.6 Gyr find...
The proportions of oxygen, carbon and major rock-forming elements (e.g. Mg, Fe, Si) determine a planet's dominant mineralogy. Variation in mineralogy subsequently affects planetary mantle dynamics as well any deep water or cycle. Through thermodynamic models high pressure diamond anvil cell experiments, we demonstrate the oxidation potential C is above that Fe at all pressures temperatures indicative 0.1 - 2 Earth-mass planets. This means for planet with (Mg+2Si+Fe+2C)/O > 1, excess will be...
After publication of our initial mass-radius-composition models for the TRAPPIST-1 system in Unterborn et al. (2018), planet masses were updated Grimm (2018). We had originally adopted data set Wang al., 2017 who reported different densities than values. The differences observed density change inferred volatile content planets. (2018) report b, d, f, g, and h as being consistent with <5 wt% water c e has having largely rocky interiors. Here, we present results recalculating fractions...
The presence of certain elements within a star, and by extension its planet, strongly impacts the formation evolution planetary system. positive correlation between host star's iron content an orbiting giant exoplanet has been confirmed; however, importance other in predicting planet occurrence is less despite their central role shaping internal structure. We designed applied machine-learning algorithm to Hypatia Catalog analyze stellar abundance patterns known stars determine those...
Abstract Lava worlds are a potential emerging population of Super-Earths that on close-in orbits around their host stars, with likely partially molten mantles. To date, few studies have addressed the impact magma observed properties planet. At ambient conditions, is less dense than solid rock; however, it also more compressible increasing pressure. Therefore, unclear how large-scale oceans affect planet observables, such as bulk density. We update ExoPlex , thermodynamically self-consistent...
Abstract Transiting planets orbiting M dwarfs provide the best opportunity to study atmospheres of rocky with current facilities. As JWST enters its second year science operations, an important initial endeavor is determine whether these have at all. are thought pose a major threat planetary due their high magnetic activity over timescales several billion years, and might completely strip atmospheres. Several Cycle 1 2 General Observers Guaranteed Time Observations programs testing this...