Mass Components Research Articles

Exploring extreme brightness variations in blue supergiant MACHO 80.7443.1718: Evidence for companion-driven enhanced mass loss

Context. The evolution of massive stars is dominated by interactions within binary and multiple systems. In order to accurately model this evolution, it is necessary to investigate all possible forms of an interaction in binary systems that may affect the evolution of the components. One of the “laboratories” plausible for this kind of investigation is the massive eccentric binary system MACHO 80.7443.1718 (ExtEV), which exhibits an exceptionally large amplitude of light variability close to the periastron passage of its 32.8-day orbit. Aims. We examine whether the light variability of ExtEV can be explained by a wind-wind collision (WWC) binary system model. We also critically review other models proposed to explain the light curve of ExtEV. Methods. We conducted an analysis of (i) the broadband multicolor photometry of ExtEV spanning a wide range of wavelengths from the ultraviolet to near-infrared, (ii) the time-series space photometry from the Transiting Exoplanet Survey Satellite (TESS), (iii) ground-based Johnson UBV photometry, and (iv) time-series high-resolution spectroscopy. To derive the parameters of the primary component of the system, we fit the spectral energy distribution (SED) and calculated evolutionary models of massive stars that included mass loss. Using radial-velocity data, we determined the spectroscopic parameters of the system. We also fit an analytical model of light variations to the TESS light curve of ExtEV. Results. The ExtEV system exhibits an infrared excess, indicating an increased mass-loss rate. The system does not match the characteristics of B[e] stars, however. We rule out the possibility of the presence of a Keplerian disk around the primary component. We also argue that the scenario with periodic Roche-lobe overflow at periastron may not be consistent with the observations of ExtEV. Analysis of the SED suggests that the primary component has a radius of about 30 R⊙ and a luminosity of ∼6.6 × 105 L⊙. With the analysis of the radial-velocity data, we refine the orbital parameters of ExtEV and find evidence for the presence of a tertiary component in the system. Using evolutionary models we demonstrate that the primary component’s mass is between 25 and 45 M⊙. We successfully reproduced the light curve of ExtEV with our analytical model, showing that the dominant processes shaping its light curve can be attributed to the atmospheric eclipse and light scattered in the WWC cone. We also estimate the primary’s mass loss rate due to stellar wind for 4.5 × 10−5 M⊙ yr−1. Conclusions. ExtEV is most likely not an extreme eccentric ellipsoidal variable, but rather an exceptional WWC binary system. The mass loss rate we derived exceeds theoretical predictions by up to two orders of magnitude. This implies that the wind in the system is likely enhanced by tidal interactions, rotation, and possibly also tidally excited oscillations. Therefore, ExtEV represents a rare evolutionary phase of a binary system that may help to understand the role of companion-driven enhanced mass loss in the evolution of massive binary systems.

Оценка скорости звездного ветра массивного компонента OAO1657-415

We discuss manifestations of the accreting neutron star in the massive X-ray binary system OAO 1657-415. We estimate the mass transfer rate between the system components within a scenario of wind-fed accretion and show that the X-ray luminosity of the pulsar can be explained only under condition that the velocity of stellar wind of the massive component in the orbital plane of the system is in the interval 200–500 km/s.

High-resolution spectroscopy of the intermediate polar EX Hydrae

EX Hya is one of the best studied, but still enigmatic intermediate polars. We present phase-resolved blue VLT/UVES high-resolution (λ/Δλ ≃ 16.000) spectra of EX Hya taken in January 2004. Our analysis involves a unique decomposition of the Balmer line profiles into the spin-modulated line wings that represent streaming motions in the magnetosphere and the orbital-phase modulated line core that represents the accretion disk. Spectral analysis and tomography show that the division line between the two is solidly located at ∣υrad ∣ ≃ 1200 km s−1, defining the inner edge of the accretion disk at rin ≃ 7 × 109 cm or ∼10R1 (WD radii). This large central hole allows an unimpeded view of the tall accretion curtain at the lower pole with a shock height up to hsh ∼ 1R1 that is required by X-ray and optical observations. Our results contradict models that advocate a small magnetosphere and a small inner disk hole. Equating rin with the magnetospheric radius in the orbital plane allows us to derive a magnetic moment of the WD of μ1 ≃ 1.3 × 1032 G cm3 and a surface field strength B1 ∼ 0.35 MG. Given a polar field strength Bp ≲ 1.0 MG, optical circular polarization is not expected. With an accretion rate Ṁ = 3.9 × 10−11 M⊙ yr−1, the accretion torque is Gacc ≃ 2.2 × 1033 g cm2 s−2. The magnetostatic torque is of similar magnitude, suggesting that EX Hya is not far from being synchronized. We measured the orbital radial-velocity amplitude of the WD, K1 = 58.7 ± 3.9 km s−1, and found a spin-dependent velocity modulation as well. The former is in perfect agreement with the mean velocity amplitude obtained by other researchers, confirming the published component masses M1 ≃ 0.79 M⊙ and M2 ≃ 0.11 M⊙.

Spectroscopic and photometric investigations of the totally eclipsing contact binary V1320 Cas

We analyzed the light curve of the total eclipse contact binary V1320 Cas, obtained reliable photometric solutions, confirmed it to be a W-type contact binary with a mass ratio of 3.404 and a contact degree of 23.9%, a cool spot is discovered on the less massive component. Orbital period analysis indicates that the period of V1320 Cas is decreasing at a rate of dPdt=1.78×10−7 day yr−1, superimposed with a cyclic modulation with a period of 1.425 yr, long-term period decrease may be caused by the combination of mass transfer and angular momentum loss, and the cyclic modulation may be caused by the third companion. Using the photometric solutions and Gaia distance, we calculated the absolute physical parameters and plotted mass-luminosity and mass–radius diagrams to analyze the evolutionary status of V1320 Cas, the more massive component is a main sequence star, while the less massive component has higher luminosity and radius than those of main sequence stars with the same mass. With the decreasing orbital period, the two components of V1320 Cas will be gradually closer, while the binary may evolve toward deep contact.

An Early Dark Matter–dominated Phase in the Assembly History of Milky Way–mass Galaxies Suggested by the TNG50 Simulation and JWST Observations

Whereas well-studied galaxies at cosmic noon are found to be baryon dominated within the effective radius, recent JWST observations of z ∼ 6–7 galaxies with stellar masses of only M * ∼ 108−9 M ⊙ surprisingly indicate that they are dark matter dominated within r e ≈ 1 kpc. Here, we place these high-redshift measurements in the context of the TNG50 galaxy formation simulation by measuring the central (within 1 kpc) stellar, gas, and dark matter masses of galaxies in the simulation. The central baryon fraction varies strongly with galaxy stellar mass in TNG50, and this M * dependence is remarkably constant across 0 < z < 6: galaxies of low stellar mass (M * ∼ 108−9 M ⊙) are dark matter dominated as f baryon(<1 kpc) ∼ 0.25. At z = 6, the baryonic mass in the centers of low-mass galaxies is largely comprised of gas, exceeding the stellar mass component by a factor ∼4. We use the simulation to track the typical evolution of such low-mass, dark matter–dominated galaxies at z = 6 and show that these systems become baryon dominated in their centers at cosmic noon, with high stellar-to-gas mass ratios, and grow to galaxies of M * ∼ 1010.5 M ⊙ at z = 0. Comparing to the dynamical and stellar mass measurements from observations at high redshifts, these findings suggest that the inferred star formation efficiency in the early Universe is broadly in line with the established assumptions for the cosmological simulations. Moreover, our results imply that the JWST observations may indeed have reached the early low-mass regime where the central parts of galaxies transition from being dark matter dominated to being baryon dominated.

A Full Accounting of the Visible Mass in SDSS MaNGA Disk Galaxies

We present a study of the ratio of visible mass to total mass in spiral galaxies to better understand the relative amount of dark matter present in galaxies of different masses and evolutionary stages. Using the velocities of the Hα emission line measured in spectroscopic observations from the Sloan Digital Sky Survey (SDSS) MaNGA Data Release 17 (DR 17), we evaluate the rotational velocity of over 5500 disk galaxies at their 90% elliptical Petrosian radii, R 90. We compare this to the velocity expected from the total visible mass, which we compute from the stellar, H i, H2, and heavy metals and dust masses. H2 mass measurements are available for only a small subset of galaxies observed in SDSS MaNGA DR17, so we derive a parameterization of the H2 mass as a function of absolute magnitude in the r band using galaxies observed as part of SDSS DR7. With these parameterizations, we calculate the fraction of visible mass within R 90 that corresponds to the observed velocity. Based on statistically analyzing the likelihood of this fraction, we conclude that the null hypothesis (no dark matter) cannot be excluded at a confidence level better than 95% within the visible extent of the disk galaxies. We also find that when all mass components are included, the ratio of visible to total mass within the visible extent of star-forming disk galaxies increases with galaxy luminosity.

TESS light curve modeling and period study of four eclipsing binaries

Abstract We reported the light curves and orbital period variations of four short-period eclipsing binaries in the Southern Hemisphere. From short-cadence time-series observations of the TESS, the intrinsic light changes rapidly with time. Δmmax and Δmmin exhibit random wave-like variations or quasi-periodicities. We deduced 14 sets of photometric solutions from the truncated light curves using the W-D program. The results imply that V757 Cen and BC Gru are near-contact binaries, whose one or two components almost fill the Roche lobes with $f&amp;gt;98{{\%}}$. Meanwhile, V535 Ara and AQ Tuc are A-subtype contact binaries. The asymmetric light curves were modelled by a cool spot assumed on a more massive component, which was used to track the stellar longitudes of starspots. Based on all available eclipsing times (ETs), including 1495 ones from TESS light curves (LCs), the orbital period variations of four binaries were analysed. The (O − C) curves are coincidentally demonstrated by the light-time effect (LITE) via the presence of the third bodies. The modulation periods approximate to 50 ∼ 60 years. In the coplanar orbit with the central binaries, the third companions’ masses are 0.105 M⊙ for V757 Cen, 0.340 M⊙ for BC Gru, 0.238 M⊙ for V535 Ara, and 0.343 M⊙ for AQ Tuc, whose systems are stable according to Harrington’s criterion. Therefore, the four short-period eclipsing binaries, V757 Cen, BC Gru, V535 Ara and AQ Tuc are hierarchical triple stellar systems.

Problems and Opportunities in the use of Bioelectrical Impedance Analysis for Assessing Body Composition During Ketogenic Diets: A Scoping Review.

The use of bioelectrical impedance analysis (BIA) for monitoring body composition during the ketogenic diet has experienced a rapid surge. This scoping review aimed to assess the validity of procedures applying BIA in the ketogenic diet and to suggest best practices for optimizing its utilization. We conducted a systematic scoping review of peer-reviewed literature involving BIA for assessing body composition in individuals adhering to a ketogenic diet. Searches of international databases yielded 1609 unique records, 72 of which met the inclusion criteria and were reviewed. Thirty-five studies used foot-to-hand technology, 34 used standing position technology, while 3 did not declare the technology used. Raw bioelectrical parameters were reported in 21 studies. A total of 196 body mass components were estimated, but predictive equations were reported in only four cases. Most research on BIA during ketogenic diets did not report the equations used for predicting body composition, making it impossible to assess the validity of BIA outputs. Furthermore, the exceedingly low percentage of studies reporting and analyzing raw data makes it challenging to replicate methodologies in future studies, highlighting that BIA is not being utilized to its full potential. There is a need for more precise technology and device characteristics descriptions, full report of raw bioelectrical data, and predictive equations utilized. Moreover, evaluating raw data through vectorial analysis is strongly recommended. Eventually, we suggest best practices to enhance BIA outcomes during ketogenic diets.

Significant Local Sea Level Variations Caused by Continental Hydrology Signals

AbstractSpace gravity missions have enabled the quantification of the mass component of sea‐level rise over the past two decades. Barystatic sea‐level rise is predominantly driven by melting polar ice sheets and mountain glaciers. However, continental hydrological processes also contribute to global sea level change at significant magnitudes. We show that for most coastal areas in low‐to‐mid latitudes, up to half of manometric sea‐level rise is due to changes in water storage in ice‐free continental regions. At other locations the direct attraction effect of anthropogenic pumping of groundwater over the duration of the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow‐On (GRACE‐FO) mission offsets sea‐level rise from ice sheet and glacier melt. If these trends in continental hydrological storage were to slow or stop, these regions would experience greatly accelerated sea‐level rise, posing a risk to coastal settlements and infrastructure, however, for most coastal communities current rates of sea‐level rise would be significantly reduced.

A photometric study of a total-eclipse contact binary V458 Mon

We present light curve solution of V458 Mon firstly by using the Wilson-Devinney code. The total eclipse and deep minima of the light curves of V458 Monenable us to determine reliable orbital parameters of the binary system. The solution suggests that V458 Monis a low mass ratio binary system with about 0.2 possessing a moderate degree of contact. The long-term period investigation showed that the period of V458 Monis increasing at dP/dt=+2.59×10−7days/yr, which could be the reason of mass transfer from the less massive component to more massive primary one, together with a periodic change. The oscillation in orbital period may be due to an unseen tertiary companion with the mass about M3=1.8M⊙ . After removing these change, there is still a weak cyclic change maybe due to magnetic activity. With the increase in orbital period of binary, the separation increases and mass ratio decreases which eventually leads V458 Montowards merger.

Associations of appendicular lean mass and abdominal adiposity with insulin resistance in older adults: A cross-sectional study.

Loss of lean muscle mass and accumulation of adipose tissue are changes associated with aging. Previous studies have documented various components of body composition as predictors for insulin resistance. The objective of this study was to investigate whether components of body composition-appendicular lean mass (ALM) and/or abdominal fat mass (AFM)-correlate with insulin resistance in older men and women. This was a cross-sectional study of 92 older men and women. Weight was classified according to body mass index (BMI)-normal (BMI <25), overweight (BMI 25-30), and obese (BMI >30). All body composition data was determined by dual energy x-ray absorptiometry (DEXA), and insulin resistance was assessed by the homeostatic model assessment of insulin resistance (HOMA-IR). Multivariable regression models with two-way interaction terms were employed to assess whether the associations between components of body composition and log HOMA varied by BMI categories. Adjusted regression showed that log HOMA was significantly associated with AFM (estimate ± standard error: 0.055 ± 0.026) and ALM (0.057 ± 0.029) for the overweight participants (p-values <0.05). Additionally, the adjusted associations between log HOMA and ALM were significantly greater for participants who were either obese or overweight compared to those with a normal BMI (p<0.002). Less consistent relationships were observed between insulin resistance and abdominal fat mass across BMI categories, whereas more consistent associations were observed between insulin resistance and appendicular lean mass in individuals with greater BMI. Further research is needed to clarify if lipid deposition within muscle tissue promotes muscle dysfunction and thereby increases risk for insulin resistance.

Discovering neutron stars with LISA via measurements of orbital eccentricity in galactic binaries

ABSTRACT The Laser Interferometer Space Antenna (LISA) will detect ∼104 Galactic binaries, the majority being double white dwarfs. However, approximately $1 \!-\! 5~{{\ \rm per\ cent}}$ of these systems will contain neutron stars which, if they can be correctly identified, will provide new opportunities for studying binary evolution pathways involving mass reversal and supernovae as well as being promising targets for multimessenger observations. Eccentricity, expected from neutron star natal kicks, will be a key identifying signature for binaries containing a neutron star. Eccentric binaries radiate at widely spaced frequency harmonics that must first be identified as originating from a single source and then analysed coherently. A multiharmonic heterodyning approach for this type of data analysis is used to perform Bayesian parameter estimation on a range of simulated eccentric LISA signals. This is used to: (i) investigate LISA’s ability to measure orbital eccentricity and to quantify the minimum detectable eccentricity; (ii) demonstrate how eccentricity and periastron precession help to break the mass degeneracy allowing the individual component masses to be inferred, potentially confirming the presence of a neutron star; (iii) investigate the possibility of source misidentification when the individual harmonics of an eccentric binary masquerade as separate circular binaries; and (iv) investigate the possibility of source reclassification, where parameter estimation results of multiple circular analyses are combined in post-processing to quickly infer the parameters of an eccentric source. The broader implications of this for the ongoing design of the LISA global fit are also discussed.

Estimating the Mass of Galactic Components Using Machine Learning Algorithms

The estimation of galactic component masses can be carried out through various approaches that involve a host of assumptions about baryon dynamics or the dark matter model. In contrast, this work introduces an alternative method for predicting the masses of the disk, bulge, stellar, and total mass using the k-nearest neighbours, linear regression, random forest, and neural network (NN) algorithms, reducing the dependence on any particular hypothesis. The ugriz photometric system was selected as the set of input features, and the training was performed using spiral galaxies in Guo’s mock catalogue from the Millennium simulation. In general, all of the algorithms provide good predictions for the galaxy’s mass from 109 M⊙ to 1011 M⊙, corresponding to the central region of the training domain. The NN algorithm showed the best performance. To validate the algorithm, we used the SDSS survey and found that the predictions of disk-dominant galaxies’ masses lie within a 99% confidence level, while galaxies with larger bulges are predicted at a 95% confidence level. The NN also reveals scaling relations between mass components and magnitudes. However, predictions for less luminous galaxies are biased due to observational limitations. Our study demonstrates the efficacy of these methods with the potential for further enhancement through the addition of observational data or galactic dynamics.

A rare clinical case of malignant ectopic retrosternal goiter of a large size in a patient with aberrant right subclavian artery

Background. Ectopic goiter accounts for only 0.2 % to 1 % of all mediastinal goiters. The aberrant right subclavian artery (arteria lusoria) is an extremely rare anomaly of the major vessel, with a prevalence not exceeding 0.3 % in the general population. This paper presents the first case of malignant ectopic retrosternal goiter of a large size in combination with the aberrant right subclavian artery. Clinical case description. A 61-year-old male presented to the thoracic surgery department of P. Herzen Moscow oncology Research institute with a large posterior mediastinal mass measuring 108×106×79 mm and adjacent to the right lobe of the thyroid gland. The tumor displaced the trachea and esophagus. Open biopsy through a thoracotomy incision revealed thyroid gland cells without signs of atypia. A detailed examination revealed mediastinal vascular anomaly – retrotracheal position of the right subclavian artery. a complete longitudinal sternotomy, complemented by a right-sided thoracotomy at the 3rd intercostal space, served as the surgical approach. The operation lasted 320 minutes, with a blood loss of 3500 ml. The postoperative period was uneventful. The morphological examination of the surgical specimen revealed nodular hyperplasia of the ectopic thyroid tissue with the growth of well-differentiated follicular carcinoma without metastatic involvement of removed lymph nodes. Considering the identified follicular carcinoma, total thyroidectomy was performed. Conclusion. In surgical planning, it is crucial to assess the location of major mediastinal vessels and their relationship with the goiter. Therefore, all patients with mediastinal lesions should undergo preoperative contrast-enhanced ct. Retrosternal goiter predisposes to a higher rate of malignancy compared to cervical goiter. If the lower edge of the goiter is at the level of or below the aortic arch, cervical access should be supplemented with sternotomy. In cases of a massive thoracic component, additional thoracotomy is justified.

Isotropic compact stars admitting Heintzmann solution in Rastall gravity

This paper is devoted to observe the physical attributes of static spherically symmetric isotropic compact stellar candidates in the context of Rastall theory of gravity. In order to inspect the structural composition of compact objects, the Heintzmann ansatz is taken into account. The unknown parameters associated with Heintzmann ansatz are evaluated through matching conditions with derived values of radii and masses of some specific star models. The consistency of the adopted ansatz is analyzed via graphical interpretation of matter variables, equation of state parameter, mass components, energy constraints, causality condition, stellar equation and adiabatic index for several choices of Rastall parameter. It is observed that the stars under consideration manifest stable structures corresponding to Heintzmann ansatz in this framework. Moreover, it is shown that for vanishing Rastall coupling parameter, the standard outcomes of general relativity can be retrieved.

Insights into heavy components evolution in the condensed volatiles from amino acids pyrolysis

Heavy components, comprised of molecules with a substantial molecular mass, are essential constituents within volatiles. Within these molecules, nitrogen-containing compounds have a tendency to undergo transformation into coke during thermal treatment, exerting a substantial impact on the efficient and secure utilization of biomass. Three amino acids- alanine with an aliphatic structure, phenylalanine with additional aromatic features, and tryptophan with an extra heterocyclic ring were selected as model compounds, individually subjected to pyrolysis within the temperature range of 450 to 650 °C. The evolution of heavy components and the associated reaction mechanisms were comprehensively explored through extensive characterization and network analysis. The results showed that alanine transformed into heavy components mainly through dehydration followed by dissociation of CH2 and CH. In contrast, phenylalanine and tryptophan tended to undergo fragmentation into C8H7N· and C12H10N2· derivatives, subsequently recombining to form heavy molecules. As the temperature increased, heavy components in alanine-derived volatiles monotonously decreased due to elimination reactions and the breaking of C–C bonds. Conversely, heavy components in phenylalanine and tryptophan initially increased and then decreased due to the enhanced cracked fragments, along with the competitive relationship between aromatization and polymerization reactions. For all three amino acids, there is a positive correlation among the average mass of heavy components, tar yield, and the intensity of permanent free radicals in the char. This implies that we may rapidly predict the evolutionary patterns of heavy components and tar through free radical detection. HCN dissociation is mathematically identified as a pivotal reaction in heavy component evolution, irrespective of amino acid type, possibly unveiling an important pathway for NOx formation. This study shows substantial theoretical significance for the eco-friendly and efficient conversion of nitrogen-rich biomass.

Calculation of the effective mass of electrons and holes of TlGaTe2 compound

Based on the band structure of TlGaTe2 compound, the extrema of the valence and conduction bands were determined and the tensor of the components of the inverse effective mass of electrons and holes was calculated.

Research on the Value of Rayleigh Damping Parameter in Explicit and Implicit Integrals for Dynamic Analysis of Large Structures

Rayleigh damping is proportional to the combination of the structural mass matrix and stiffness matrix and is widely used in structural seismic analysis. The accuracy of seismic analysis of nuclear power structures directly depends on the value of the Rayleigh damping parameters. However, the stiffness component of Rayleigh damping is not included in the explicit integral, so the Rayleigh damping in the explicit and implicit integrals needs to be handled differently. LS-DYNA R11.1.0 software provides various calculation methods for the value of the Rayleigh damping parameter in the explicit integral. To investigate the influence of the value of the Rayleigh damping parameter in the explicit and implicit integrals on the results of the dynamic analysis of a nuclear power plant, the AP1000 nuclear island plant is taken as an example, and the explicit and implicit dynamic calculation are carried out respectively for the nuclear power plant, considering the soil–structure interaction. The results show that the Rayleigh damping parameter calculated by different methods in the explicit integral has a large influence on the results of seismic analysis of nuclear power plants. The mass component of Rayleigh damping in the explicit and implicit integrals takes the same value, and the stiffness component of Rayleigh damping in the explicit integrals is taken as the negative of the stiffness component in the implicit integrals. Thus, the results of the two dynamic analyses can be in good agreement. The results provide a reference for the application of Rayleigh damping in the explicit integral for the seismic analysis of nuclear power structures.

Toward Early-type Eclipsing Binaries as Extragalactic Milestones. III. Physical Properties of the O-type Eclipsing Binary OGLE LMC-ECL-21568 in a Quadruple System* , *Based on observations collected at the European Southern Observatory, Chile. † † This paper includes data gathered with the 6.5 m Magellan Clay Telescope at Las Campanas Observatory, Chile.

We present the results from a complex study of an eclipsing O-type binary (Aa+Ab) with the orbital period of P A = 3.2254367 days that forms part of a higher-order multiple system in a configuration of (A+B)+C. We derived masses of the Aa+Ab binary of M 1 = 19.02 ± 0.12 and M 2 = 17.50 ± 0.13 M ⊙, the radii of R 1 = 7.70 ± 0.05 and R 2 = 6.64 ± 0.06 R ⊙, and temperatures of T 1 = 34,250 ± 500 K and T 2 = 33,750 ± 500 K. From the analysis of the radial velocities, we found a spectroscopic orbit of A in the outer A+B system with P A+B = 195.8 days (P A+B/P A ≈ 61). In the O − C analysis, we confirmed this orbit and found another component orbiting the A+B system with P AB+C = 2550 days (P AB+C/P A+B ≈ 13). From the total mass of the inner binary and its outer orbit, we estimated the mass of the third object, M B ≳ 10.7 M ⊙. From the light travel time effect fit to the O − C data, we obtained the limit for the mass of the fourth component, M C ≳ 7.3 M ⊙. These extra components contribute about 20%–30% (increasing with wavelength) to the total system light. From the comparison of model spectra with the multiband photometry, we derived a distance modulus of 18.59 ± 0.06 mag, a reddening of 0.16 ± 0.02 mag, and an RV of 3.2. This work is part of our ongoing project, which aims to calibrate the surface brightness–color relation for early-type stars.

Predictive sustainability analysis applied to an automotive design case study.

The paper deals with a predictive sustainability analysis applied to the design of automotive components in lightweight perspective. The analysis is conducted through the integration of the traditional Life Cycle Assessment (LCA) methodology with tailored forecasting algorithms able to provide a predictive evaluation of Climate Change (CC) by elaboration data contained in commercial environmental datasets. The comparison is referred to the entire Life Cycle (LC) of the system (including production, use and End-of-Life) according to a “from cradle to grave approach”.A medium-class car rear crash management system is used as case study, assessing the potential benefits related to the substitution of conventional steel with 6000/7000 series aluminium alloys, along with other minor design changes. Particularly, the study compares the environmental profile of the two solutions based on the CC impact category in application to both an Internal Combustion Engine Vehicle (ICEV) and a Battery Electric Vehicle (BEV).The results show the potentiality of the proposed methodology, highlighting possible improvements/worsenings: new materials and manufacturing technologies adopted in the lightweight rear crash management system entail contrasting environmental effects depending on LC phases, that is, increased CO2eq in production (around 125% - mainly due to the strong energy intensity of aluminium supply chain) and reduced burdens in use and EoL (primarily provided by component mass reduction). That said, the influence of different boundary conditions on the predictive models is significant only for the electricity produced to energize the BEV configuration, leading to an overall variability of comparison results ranging within 3-30% for the BEV case study.