Protoplanetary Disks Research Articles

ISLAT: the Interactive Spectral-line Analysis Tool for JWST and Beyond

We present the Interactive Spectral-Line Analysis Tool (iSLAT), a python-based graphical tool that allows users to interactively explore, inspect, and fit line emission observed in molecular spectra. iSLAT adopts a simple slab model in LTE that simulates emission spectra with a small set of parameters (temperature, emitting area, column density, and line broadening) that users can adjust in real time for multiple molecules or multiple thermal components of a same molecule. A central feature of iSLAT is the possibility to interactively inspect individual lines or line clusters to visualize their properties at high resolution and identify them in the population diagram. iSLAT provides a number of additional features, including the option to identify lines that are not blended at the instrumental resolution, the possibility to save custom line lists selected by the user, and to fit and measure their properties (line flux, width, and centroid) for later analysis. In this paper we launch the tool and demonstrate it on infrared spectra from the James Webb Space Telescope and ground-based instruments that provide higher resolving power. We also share curated line lists that are useful for the analysis of the forest of water emission lines observed from protoplanetary disks. iSLAT is shared with the community on GitHub.

P adé: A Code for Protoplanetary Disk Turbulence Based on Padé Differencing

The Padé code has been developed to treat hydrodynamic turbulence in protoplanetary disks. It solves the compressible equations of motion in cylindrical coordinates. Derivatives are computed using nondiffusive and conservative fourth-order Padé differencing, which has higher resolving power compared to both dissipative shock-capturing schemes used in most astrophysics codes, as well as nondiffusive central finite-difference schemes of the same order. The fourth-order Runge–Kutta method is used for time stepping. A previously reported error-corrected Fargo approach is used to reduce the time step constraint imposed by rapid Keplerian advection. Artificial bulk viscosity is used when shock capturing is required. Tests for correctness and scaling with respect to the number of processors are presented. Finally, efforts to improve efficiency and accuracy are suggested.

Unveiling the internal structure and formation history of the three planets transiting HIP 29442 (TOI-469) with CHEOPS

Multiplanetary systems spanning the radius valley are ideal testing grounds for exploring the different proposed explanations for the observed bimodality in the radius distribution of close-in exoplanets. One such system is HIP 29442 (TOI-469), an evolved K0V star hosting two super-Earths and one sub-Neptune. We observed HIP 29442 with CHEOPS for a total of 9.6 days, which we modelled jointly with two sectors of TESS data to derive planetary radii of 3.410 ± 0.046, 1.551 ± 0.045, and 1.538 ± 0.049 R⊕ for planets b, c, and d, which orbit HIP 29442 with periods of 13.6, 3.5, and 6.4 days, respectively. For planet d this value deviates by more than 3σ from the median value reported in the discovery paper, leading us to conclude that caution is required when using TESS photometry to determine the radii of small planets with low per-transit signal-to-noise ratios and large gaps between observations. Given the high precision of these new radii, combining them with published RVs from ESPRESSO and HIRES provides us with ideal conditions to investigate the internal structure and formation pathways of the planets in the system. We introduced the publicly available code plaNETic, a fast and robust neural network-based Bayesian internal structure modelling framework. We then applied hydrodynamic models to explore the upper atmospheric properties of these inferred structures. Finally, we identified planetary system analogues in a synthetic population generated with the Bern model for planet formation and evolution. Based on this analysis, we find that the planets likely formed on opposing sides of the water iceline from a protoplanetary disk with an intermediate solid mass. We finally report that the observed parameters of the HIP 29442 system are compatible with a scenario where the second peak in the bimodal radius distribution corresponds to sub-Neptunes with a pure H/He envelope and with a scenario with water-rich sub-Neptunes.

Obliquity Constraints for the Extremely Eccentric Sub-Saturn Kepler-1656 b

The orbits of close-in exoplanets provide clues to their formation and evolutionary history. Many close-in exoplanets likely formed far out in their protoplanetary disks and migrated to their current orbits, perhaps via high-eccentricity migration (HEM), a process that can also excite obliquities. A handful of known exoplanets are perhaps caught in the act of HEM, as they are observed on highly eccentric orbits with tidal circularization timescales shorter than their ages. One such exoplanet is Kepler-1656 b, which is also the only known nongiant exoplanet (<100 M ⊕) with an extreme eccentricity (e = 0.84). We measured the sky-projected obliquity of Kepler-1656 b by observing the Rossiter–McLaughlin effect during a transit with the Keck Planet Finder. Our data are consistent with an aligned orbit but are also consistent with moderate misalignment with λ < 50° at 95% confidence, with the most likely solution of 35.0−21.6+14.9 deg. A low obliquity would be an unlikely outcome of most eccentricity-exciting scenarios, but we show that the properties of the outer companion in the system are consistent with the coplanar HEM mechanism. Alternatively, if the system is not relatively coplanar (≲20° mutual inclination), Kepler-1656 b may be presently at a rare snapshot of long-lived eccentricity oscillations that do not induce migration. Kepler-1656 b is only the fourth exoplanet with e > 0.8 to have its obliquity constrained; expanding this population will help establish the degree to which orbital misalignment accompanies migration. Future work that constrains the mutual inclinations of outer perturbers will be key for distinguishing plausible mechanisms.

Concurrent Accretion and Migration of Giant Planets in Their Natal Disks with Consistent Accretion Torque

Migration commonly occurs during the epoch of planet formation. For emerging gas giant planets, it proceeds concurrently with their growth through the accretion of gas from their natal protoplanetary disks. A similar migration process should also be applied to the stellar-mass black holes embedded in active galactic nucleus disks. In this work, we perform high-resolution 3D and 2D numerical hydrodynamical simulations to study the migration dynamics for accreting embedded objects over the disk viscous timescales in a self-consistent manner. We find that an accreting planet embedded in a predominantly viscous disk has a tendency to migrate outward, in contrast to the inward orbital decay of nonaccreting planets. 3D and 2D simulations find the consistent outward migration results for the accreting planets. Under this circumstance, the accreting planet’s outward migration is mainly due to the asymmetric spiral arms feeding from the global disk into the Hill radius. This is analogous to the unsaturated corotation torque although the imbalance is due to material accretion within the libration timescale rather than diffusion onto the inner disk. In a disk with a relatively small viscosity, the accreting planets clear deep gaps near their orbits. The tendency of inward migration is recovered, albeit with suppressed rates. By performing a parameter survey with a range of disks’ viscosity, we find that the transition from outward to inward migration occurs with the effective viscous efficiency factor α ∼ 0.003 for Jupiter-mass planets.

Shoulder of Dust Rings Formed by Planet–Disk Interactions

Recent analyses of millimeter-wavelength protoplanetary disk observations have revealed several emission excesses on the previously identified dust rings, referred to as dust shoulders. The prevalence of dust shoulders suggests that they trace a common but unclear mechanism. In this work, we combine 3D, multifluid hydrodynamic simulations with radiative transfer calculations to explain the formation of dust shoulders. We find that the ring-shoulder pairs can result from the 3D planet–disk interactions with massive, gap-opening planets. The key driver is the dust filtration effect at the local pressure maximum due to planet-driven outward gas flows. Our work provides a possible explanation for the outer dust shoulders in recent super-resolution analyses of Atacama Large Millimeter/submillimeter Array observations. It also provides insights into the formation of the inner dust shoulder in the PDS 70 disk and highlights the role of 3D effects in planet–disk interaction studies.

A Survey of Protoplanetary Disks Using the Keck/NIRC2 Vortex Coronagraph

Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations of protoplanetary disks in the millimeter continuum have shown a variety of radial gaps, cavities, and spiral features. These substructures may be signposts for ongoing planet formation, and therefore these systems are promising targets for direct imaging planet searches in the near-infrared. To this end, we present results from a deep imaging survey in the L′ band (3.8 μm) with the Keck/NIRC2 vortex coronagraph to search for young planets in 43 disks with resolved features in the millimeter continuum or evidence for gaps/central cavities from their spectral energy distributions. Although we do not detect any new point sources, using the vortex coronagraph allows for high sensitivity to faint sources at small angular separations (down to ∼0.″1), allowing us to place strong upper limits on the masses of potential gas giant planets. We compare our mass sensitivities to the masses of planets derived using ALMA observations, and while we are sensitive to ∼1 M Jup planets in the gaps in some of our systems, we are generally not sensitive to planets of the masses expected from the ALMA observations. In addition to placing upper limits on the masses of gas giant planets that could be interacting with the dust in the disks to form the observed millimeter substructures, we are also able to map the micron-sized dust as seen in scattered light for 8 of these systems. Our large sample of systems also allows us to investigate limits on planetary accretion rates and disk viscosities.

Combining reference-star and angular differential imaging for high-contrast imaging of extended sources

Context. High-contrast imaging (HCI) is a technique designed to observe faint signals near bright sources, such as exoplanets and circumstellar disks. The primary challenge in revealing the faint circumstellar signal near a star is the presence of quasi-static speckles, which can produce patterns on the science images that are as bright, or even brighter, than the signal of interest. Strategies such as angular differential imaging (ADI) or reference-star differential imaging (RDI) aim to provide a means of removing the quasi-static speckles in post-processing. Aims. In this paper, we present and discuss the adaptation of state-of-the-art algorithms, initially designed for ADI, to jointly leverage angular and reference-star differential imaging (ARDI) for the direct HCI of circumstellar disks. Methods. Using a collection of HCI datasets, we assessed the performance of ARDI in comparison to ADI and RDI based on iterative principal component analysis (IPCA). These diverse datasets were acquired under various observing conditions and include the injection of synthetic disk models at various contrast levels. We also considered reference stars with different levels of correlation with the science targets. Results. Our results demonstrate that ARDI with IPCA improves the quality of recovered disk images and the sensitivity to planets embedded in disks, compared to ADI or RDI individually. This enhancement is particularly pronounced when dealing with extended sources exhibiting highly ambiguous structures that cannot be accurately retrieved using ADI alone, and when the quality of the reference frames is suboptimal, leading to an underperformance of RDI. We finally applied our method to a sample of real observations of protoplanetary disks taken in star-hopping mode, and propose to revisit the protoplanetary claims associated with these disks. Among eight proposed protoplanets claimed through velocity kinks or direct imaging, none of them were re-detected in our new processed images.

A Multiwavelength, Multiepoch Monitoring Campaign of Accretion Variability in T Tauri Stars from the ODYSSEUS Survey. II. Photometric Light Curves

Classical T Tauri stars (CTTSs) are young, low-mass stars that accrete material from their surrounding protoplanetary disk. To better understand accretion variability, we conducted a multiepoch, multiwavelength photometric monitoring campaign of four CTTSs, TW Hya, RU Lup, BP Tau, and GM Aur, in 2021 and 2022, contemporaneous with Hubble Space Telescope UV and optical spectra. We find that all four targets display significant variability in their light curves, generally on days-long timescales (but in some cases year-to-year), often due to periodicity associated with stellar rotation and to stochastic accretion variability. There is a strong connection between mass accretion and photometric variability in all bands, but the relationship varies per target and epoch. Thus, photometry should be used with caution as a direct measure of accretion in CTTSs.

JWST study of the DG Tau B disk-wind candidate

Context. The origin of outflows and their impact on protoplanetary disk evolution and planet-formation processes are still crucial open questions. DG Tau B is a Class I protostar associated with a structured disk and a rotating conical CO outflow and was recently identified by ALMA as one of the best CO disk wind candidate. It is therefore a perfect target for studying these questions. Aims. We aim to map and study any outflow component intermediate between the axial jet and the CO outflow in order to constrain the origin (irradiated or shocked disk wind or swept-up material) of the redshifted molecular outflows in DG Tau B. Methods. We analyzed observations obtained with James Webb Space Telescope NIRSpec-IFU and NIRCam, supplemented with IFU data from the SINFONI/VLT instrument. We investigated the morphology, kinematics, and excitation conditions of the ro-vibrational H2 emission lines and their relation with the atomic jet and CO outflow. We focus our analysis on the redshifted outflow lobe. Results. We observe a global layered structure of the redshifted outflows in DG Tau B, with the atomic jet inside the H2 cavity, which in turn is nested inside the CO conical outflow. We also find temperature, velocity, and collimation to be increasing towards the axis of the flow. The redshifted H2 emission traces a narrow conical cavity (semi-opening angle of 9.4°) that is wider than the axial jet but nested just inside the CO outflow. Both the jet and the H2 cavity originate from the innermost regions of the disk (r0 &lt; 6 au). The redshifted H2 cavity flows with a constant vertical velocity of Vz = 22.5 ± 0.8 km s−1, twice faster than the conical CO flow. The excitation conditions imply a hot H2 gas (Tex ≃ 2200 K) with an average mass flux of Ṁ(H2) = 3 × 10−11 M⊙ yr−1, which is significantly lower than the jet and CO values. Conclusions. The global layered H2-CO structure in temperature, velocity, and collimation in the DG Tau B redshifted lobe is consistent with a magneto-hydrodynamic disk wind scenario. The hot H2 could trace the inner, dense photodissociation layer in the wind. An H2 launching region at disk radii of 0.2−0.4 au combined with a large ejection efficiency (ξ ≃ 1) would account for the mass flux and kinematics. Alternatively, the near-IR ro-vibrational H2 could be emitted in the interaction layer driven by successive jet bow shocks into an outer disk wind or envelope. Further constraints on both scenarios will be obtained from the analysis of MIRI observations.

Insights on the Formation Conditions of Uranus and Neptune from Their Deep Elemental Compositions

This study, placed in the context of the preparation for the Uranus Orbiter Probe mission, aims to predict the bulk volatile compositions of Uranus and Neptune. Using a protoplanetary disk model, it examines the evolution of trace species through vapor and solid transport as dust and pebbles. Due to the high carbon abundance found in their envelopes, the two planets are postulated to have formed at the carbon monoxide ice line within the protosolar nebula. The time evolution of the abundances of the major volatile species at the location of the CO ice line is then calculated to derive the abundance ratios of the corresponding key elements, including the heavy noble gases, in the feeding zones of Uranus and Neptune. Supersolar metallicity in their envelopes likely results from accreting solids in these zones. Two types of solids are considered: pure condensates (Case 1) and a mixture of pure condensates and clathrates (Case 2). The model, calibrated to observed carbon enrichments, predicts deep compositions. In Case 1, argon is deeply depleted, while nitrogen, oxygen, krypton, phosphorus, sulfur, and xenon are significantly enriched relative to their protosolar abundances in the two planets. Case 2 predicts significant enrichments for all species, including argon, relative to their protosolar abundances. Consequently, Case 1 predicts near-zero Ar/Kr or Ar/Xe ratios, while Case 2 suggests that these ratios are 0.1 and 0.5–1 times their protosolar ratios, respectively. Both cases predict a bulk sulfur-to-nitrogen ratio consistent with atmospheric measurements.

Giant planet formation in the Solar System

The formation history of Jupiter has been of interest due to its ability to shape the solar system’s history. Yet little attention has been paid to the formation and growth of Saturn and the other giant planets. Here we explore through N-body simulations the implications of the simplest disc and pebble accretion model with steady-state accretion and an assumed ring structure in the disc at 5 AU on the formation of the giant planets in the solar system. We conducted a statistical survey of different disc parameters and initial conditions of the protoplanetary disc to establish which combination best reproduces the present outer solar system. We examined the effect of the initial planetesimal disc mass, the number of planetesimals and their size-frequency distribution slope, pebble accretion prescription and sticking efficiency on the likelihood of forming gas giants and their orbital distribution. The results reveal that the accretion sticking efficiency is the most sensitive parameter to control the final masses and number of giant planets. We have been unable to replicate the formation of all three types of giant planets in the solar system in a single simulation. The probability distribution of the final location of the giant planets is approximately constant in logr, suggesting there is a slight preference for formation closer to the Sun but no preference for more massive planets to form closer. The eccentricity distribution has a higher mean for more massive planets indicating that systems with more massive planets are more violent. We compute the average formation time for proto-Jupiter to reach 10 Earth masses to be 〈tc,J〉=1.1±0.3 Myr and for proto-Saturn 〈tc,S〉=3.3±0.4 Myr, while for the ice giants this increases to 〈tc,I〉=4.9±0.1 Myr. The formation timescales of the cores of the gas giants are distinct at >95% confidence, suggesting that they formed sequentially.

Compaction during fragmentation and bouncing produces realistic dust grain porosities in protoplanetary discs

Context. In protoplanetary discs, micron-sized dust grows to form millimetre- to centimetre-sized pebbles but encounters several barriers during its evolution. Collisional fragmentation and radial drift impede further dust growth to planetesimal size. Fluffy grains have been hypothesised to solve these problems. While porosity leads to faster grain growth, the implied porosity values obtained from previous simulations were larger than suggested by observations. Aims. In this paper, we study the influence of porosity on dust evolution, taking into account growth, bouncing, fragmentation, compaction, rotational disruption, and snow lines, in order to understand their impact on dust evolution. Methods. We developed a module for porosity evolution for the 3D smoothed particle hydrodynamics code PHANTOM that accounts for dust growth and fragmentation. This mono-disperse model is integrated into both a 1D code and the 3D code to capture the overall evolution of dust and gas. Results. We show that porosity helps dust growth and leads to the formation of larger solids than when considering compact grains, as predicted by previous work. Our simulations taking into account compaction during fragmentation show that large millimetre grains are still formed but are ten to 100 times more compact. Thus, millimetre sizes with typical filling factors of ~0.1 match the values measured on comets or via polarimetric observations of protoplanetary discs.

The rapid formation of macromolecules in irradiated ice of protoplanetary disk dust traps

The rapid formation of macromolecules in irradiated ice of protoplanetary disk dust traps

Tribocharged solids in protoplanetary discs: internal and external discharge time-scales

ABSTRACT Particles regularly tribocharge in collisions. Here, we study how long charges can persist on such particles in the environment of a protoplanetary disc. We set up three complementary experiments to quantify discharge time-scales. We first directly measure the time dependency of charge on triboelectrically charged objects. For this aspect, we performed two long-time experiments under different environmental conditions. We find that the charge persists on the tribocharged bodies on time-scales between minutes and years. Discharge might be mediated by external ions or internally, by conduction. To constrain the latter, we also determined the specific electric resistance of dust samples as simulants for dust aggregates in protoplanetary discs. In this third experiment, we see an increase in resistivity at decreasing ambient pressure up to the limit of the instrument. These findings are consistent with the assumption that water on all relevant surfaces including dust grains within the pore space of aggregates is the main driver of discharge. Under disc conditions, the charge might persist for weeks to years. This leaves net-charged isolated grains in dense parts of the mid-plane of protoplanetary discs charged in between collisions.

On Kinematic Measurements of Self-gravity in Protoplanetary Disks

Using controlled injection and recovery experiments, we devised an analysis prescription to assess the quality of dynamical measurements of protoplanetary disk gas masses based on resolved (CO) spectral line data, given observational limitations (resolution, sampling, noise), measurement bias, and ambiguities in the geometry and physical conditions. With sufficient data quality, this approach performed well for massive disks (M d/M * = 0.1): we inferred M d posteriors that recovered the true values with little bias (≲20%) and uncertainties within a factor of two (2σ). The gas surface density profiles for such cases are recovered with remarkable fidelity. Some experimentation indicates that this approach becomes insensitive when M d/M * ≲ 5%, due primarily to degeneracies in the surface density profile parameters. Including multiple lines that probe different vertical layers, along with some improvements in the associated tools, might push that practical boundary down by another factor of ∼two in ideal scenarios. We also demonstrated this analysis approach using archival Atacama Large Millimeter/Submillimeter Array observations of the MWC 480 disk: we measured Md=0.13−0.01+0.04M⊙ (corresponding to M d/M * = 7% ± 1%) and identified kinematic substructures consistent with surface density gaps around 65 and 135 au. Overall, this (and similar work) suggests that these dynamical measurements offer powerful new constraints with sufficient accuracy and precision to quantify gas masses and surface densities at the high end of the M d/M * distribution, and therefore can serve as key benchmarks for detailed thermo-chemical modeling. We address some prospects for improvements, and discuss various caveats and limitations to guide future work.

Properties of outer solar system pebbles during planetesimal formation from meteor observations

Observations of proto-planetary disks, as well as theoretical modeling, suggest that in the late stages of accretion leading up to the formation of planetesimals, particles grew to pebbles the size of 1-mm to tens of cm, depending on the location and ambient conditions in the disk. That is the same size range that dominates the present-day comet and primitive asteroid mass loss. Meteoroids that size cause visible meteors on Earth. Here, we hypothesize that the size distribution and the physical and chemical properties of young meteoroid streams still contain information about the conditions in the solar nebula during these late stages of accretion towards planetesimal formation. If so, they constrain where long-period (Oort Cloud) comets, Jupiter-family (Scattered Disk Kuiper Belt) comets, and primitive asteroids (Asteroid Belt) formed. From video and visual observations of 47 young meteor showers, we find that freshly ejected meteoroids from long-period comets tend to have low bulk density and are distributed with equal surface area per log-mass interval (magnitude distribution index χ ∼ 1.85), suggesting gentle accretion conditions. Jupiter-family comets, on the other hand, mostly produce meteoroids twice as dense and distributed with a steeper χ ∼ 2.15 or even χ ∼ 2.5, which implies that those pebbles grew from particles fragmenting in a collisional cascade or by catastrophic collisions, respectively. Some primitive asteroids show χ > 2.5, with most mass in small particles, indicating an even more aggressive fragmentation by processes other than mutual collisions. Both comet populations contain an admixture of compact materials that are sometimes sodium-poor, but Jupiter-family comets show a higher percentage (∼8% on average) than long-period comet showers (∼4%) and a wider range of percentages among comets. While there are exceptions in both groups, the implication is that most long-period comets formed under gentle particle growth conditions, possibly near the 30 AU edge of the Trans Neptunian Disk, while most Jupiter family comets formed closer to the Sun where pebbles reached or passed the fragmentation barrier, and primitive asteroids formed in the region where the cores of the giant planets formed. This is possible if the Scattered Disk represents all objects scattered by Neptune during its migration, while the present-day outer Oort cloud formed only during and after the time of the planet instability, well after the Sun had moved away from sibling stars.

Warps and breaks in circumbinary discs

ABSTRACT Disc warping, and possibly disc breaking, has been observed in protoplanetary discs around both single and multiple stars. Large warps can break the disc, producing multiple observational signatures. In this work, we use comparisons of disc time-scales to derive updated formulae for disc breaking, with better predictions as to when and where a disc is expected to break and how many breaks could occur. Disc breaking is more likely for discs with small inner cavities, cooler temperatures, and steeper power-law profiles, such that thin, polar-aligning discs are more likely to break. We test our analytical formulae using three-dimensional grid-based simulations of protoplanetary discs warped by the gravitational torque of an inner binary. We reproduce the expected warp behaviours in different viscosity regimes and observe disc breaking at locations in agreement with our derived equations. As our simulations only show disc breaking when disc viscosity is low, we also consider a viscous criterion for disc breaking, where rapid alignment to the precession vector can prevent a break by reducing the maximum misalignment between neighbouring rings. We apply these results to the GW Orionis circumtriple disc and find that the precession induced from the central stars can break the disc if it is relatively thin. We expect repeated or multiple disc breaking to occur for discs with sufficiently steep power-law profiles. We simulate a polar-aligning disc around an eccentric binary with steep power-law profiles and observe two separate breaking events at locations in rough agreement with our analytical predictions.

Isotopic variation of non-carbonaceous meteorites caused by dust leakage across the Jovian gap in the solar nebula

Abstract High-precision isotopic measurements of meteorites revealed that they are classified into non-carbonaceous (NC) and carbonaceous (CC) meteorites. One plausible scenario for achieving this grouping is the early formation of Jupiter, because massive planets can create gaps that suppress the mixing of dust across the gap in protoplanetary disks. However, the efficiency of this suppression by the gaps depends on dust size and the strength of turbulent diffusion, allowing some fraction of the dust particles to leak across the Jovian gap. In this study, we investigate how isotopic ratios of NC and CC meteorites are varied by the dust leaking across the Jovian gap in the solar nebula. To do this, we constructed a model to simulate the evolution of the dust size distribution and the $^{54}$Cr-isotopic anomaly $\varepsilon ^{54}$Cr in isotopically heterogeneous disks with Jupiter. Assuming that the parent bodies of NC and CC meteorites are formed in two dust-concentrated locations inside and outside Jupiter’s orbit, referred to as the NC reservoir and the CC reservoir, we derive the temporal variation of $\varepsilon ^{54}$Cr at the NC and CC reservoirs. Our results indicate that substantial contamination from CC materials occurs at the NC reservoir in the fiducial run. Nevertheless, the values of $\varepsilon ^{54}$Cr at the NC reservoir and the CC reservoir in the run are still consistent with those of NC and CC meteorites formed around $2\:$Myr after the formation of calcium–aluminum-rich inclusions (Sugiura &amp; Fujiya 2014, Meteorit. Planet. Sci., 49, 772). Moreover, this dust leakage causes a positive correlation between the $\varepsilon ^{54}$Cr value of NC meteorites and the accretion ages of their parent bodies.

The Empirical and Radiative Transfer Hybrid (EaRTH) Disk Model: Merging Analyses of Protoplanetary Dust Disk Mineralogy and Structure

Our understanding of how exoplanets form and evolve relies on analyses of both the mineralogy of protoplanetary disks and their detailed structures; however, these key complementary aspects of disks are usually studied separately. We present initial results from a hybrid model that combines the empirical characterization of the mineralogy of a disk, as determined from its mid-infrared spectral features, with the MCFOST radiative transfer disk model, a combination we call the Empirical and Radiative Transfer Hybrid (EaRTH) Disk Model. With the results of the mineralogy detection serving as input to the radiative transfer model, we generate mid-infrared spectral energy distributions (SEDs) that reflect both the mineralogical and structural parameters of the corresponding disk. Initial fits of the SED output by the resulting integrated model of Spitzer Space Telescope mid-infrared spectra of the protoplanetary disk orbiting the nearby T Tauri star MP Mus demonstrate the potential advantages of this approach by revealing details like the dominance of micron-sized olivine and micron-sized forsterite in this dusty disk. The simultaneous insight into disk composition and structure provided by the EaRTH Disk methodology should be directly applicable to the interpretation of mid-infrared spectra of protoplanetary disks that will be produced by the James Webb Space Telescope.