Extreme Mass Research Articles

Proximal-type epithelioid sarcoma: A new case report

Epithelioid sarcoma (ES) is a rare high-grade soft tissue sarcoma, first described by Enzinger in 1970, classically presenting as a subcutaneous or deep dermal mass in the distal extremities of adolescents and young adults. In 1997, Guillou et al. described the proximal-type epithelioid sarcoma, which is found mostly in the pelvic, perineal regions, and genital tracts of young to middle-aged adults. Epithelioid sarcoma is characterized by a proliferation of epithelioid-like cells with rhabdoid features and the absence of a granuloma-like pattern. We present, in this paper, a case of proximal-type epithelioid sarcoma of abdominal wall, with an aggressive clinical course, including distant metastasis and death one month after diagnosis. In this particular case, the location is infrequent, and it had not previously been described.

Weak gravity conjecture of charged-rotating-AdS black hole surrounded by quintessence and string cloud

A series of corrections to general relativity have recently been applied to find the relationship between entropy and extremality-bound black holes. This relationship has been investigated for many black holes, such as charged AdS, rotating, and massive gravity black holes. We give a minor constant correction to the action and confirm these universal relations for a charged-rotating-AdS black hole. We then examine these calculations for the black hole, surrounded by the quintessence and the cloud of string. In this paper, we evaluate a new universal relation. It means that we find the relation between the extremal mass of the black hole and the factor of cloud string and observe that the corresponding universal relation is well established. We find that the quintessence terms play a very effective role in calculating the mass-charge ratio and concept of weak gravity conjecture of black holes. We note here that the added constant correction is inversely related to the entropy of the black hole. It leads us to see that the mass-to-charge ratio decreases and fully confirms the black hole's weak gravity conjecture (WGC).

Microstructure characteristics and degradation behaviors of medical rare-earth Mg-10.6Gd-0.3Ag-x(Y/Zn) alloys in vitro

Due to excellent biological-functionality, unique/suitable elastic-modulus as well as spontaneous degradation behaviors, Mg alloys acted as medical implants have shown enormous potential in surgical operation and bone-fixation fields. Unfortunately, the extreme mass loss and unmarked-fracture could easily induce the implant failure. In the present study, the microstructure characteristics and degradation behaviors of the Mg-10.6Gd-0.3Ag-x(Y/Zn) alloys were investigated through the XRD, TEM, EPMA, XPS, 3D/CLSM and SECM. Results revealed that with the increment of Y/Zn contents, the amount of Mg24(Gd/Y)5 precipitates increased, which were mainly distributed in grains and on grain boundaries. The addition of Zn and Y increased the undercooling and Y had a large mismatch degree with Mg atoms, which could promote the precipitation of second phases. Additionally, the corrosion rates of Mg-10.6Gd-0.3Ag-x(Y/Zn) increased firstly and then reduced. Also, the best corrosion resistance was achieved in the Mg-10.6Gd-0.3Ag-Y-Zn, with the current intensities of 58.49 μA/cm2, attributed to the formation of continuous reticular structure oxide film, which can act as physical barriers and impede the corrosion process.

Detecting secondary spin with extreme mass ratio inspirals in scalar-tensor theory* *Supported by the National Key Research and Development Program of China (2020YFC2201400), Yun-Gui Gong acknowledges the support by the National Key Research and Development Program of China (2020YFC2201504), Chao Zhang was supported by the China Postdoctoral Science Foundation (2023M742297), Brazilian agencies Fundação de Amparo à Pesquisa do Estado de

In this study, we investigate the detectability of the secondary spin in an extreme mass ratio inspiral (EMRI) system within a modified gravity model coupled with a scalar field. The central black hole, which reduces to a Kerr one, is circularly spiralled by a scalar-charged spinning secondary body on the equatorial plane. The analysis reveals that the presence of the scalar field amplifies the secondary spin effect, allowing for a lower limit of the detectability and an improved resolution of the secondary spin when the scalar charge is sufficiently large. Our findings suggest that secondary spin detection is more feasible when the primary mass is not large, and TianQin is the optimal choice for detection.

Conservative scattering of Reissner-Nordström black holes at third post-Minkowskian order

Using a recently developed effective field theory formalism for extreme mass ratios arXiv:2308.14832, we present a calculation of charged black hole scattering at third post-Minkowskian order. The charges and masses are kept arbitrary, and the result interpolates from the scattering of Schwarzschild to extremal charged black holes, and beyond to charged particles in electrodynamics — agreeing with previously reported results in all such limits. The computation of the radial action is neatly organized in powers of the mass ratio. The probe (0SF) contributions are readily computed by direct integration of the radial momentum, and we use the effective field theory to compute the subleading (1SF) contributions via background-field Feynman rules supplemented by an operator encoding recoil of the background. Together these contributions completely determine the conservative physics at order OG3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O}\\left({G}^3\\right) $$\\end{document}.

Intralesional Kenalog Injections for Recurrent Cutaneous Rosai-Dorfman Disease (RDD) in the Lower Extremity

Rosai-Dorfman disease (RDD) is a rare disorder of histiocytic origin with nodal, extranodal, and cutaneous classifications often presenting as eruptive rashes, most commonly affecting the face, trunk, and thigh. Due to its rarity, no consensus exists regarding standard of care for these lesions, as most knowledge regarding treatment is provided by case reports. To our knowledge, we report the first case of a patient with a recurrent lower extremity mass consistent with cutaneous RDD, despite surgical excision and topical steroids treatment. A 51-year-old female presented with recurrent RDD after failed treatment with clobetasol ointment and surgical excision at an outside practice. Examination revealed violaceous plaques with overlying scale, without lymphadenopathy. With the failure of the previous excision, the patient was prescribed 5 mg/ml intralesional Kenalog (ILK) injections to suppress inflammation of the lesion. She experienced improved clinical response to treatment and remission of active disease with residual post-inflammatory hyperpigmentation at 10 months after two rounds of injections, although the patient reported vast improvement at 5 months as well. Treatment of RDD is difficult due to its rarity, hindering clinical trial development. Therapeutics reported to be efficacious include topical, intralesional, and systemic steroids, retinoids, methotrexate, chemotherapy, cryotherapy, phototherapy, and radiation. Clinical management is variable and often requires multiple forms of treatment on a case-to-case basis, highlighting the need for larger clinical studies to establish a standard of care. Our case poses interest in the use of ILK for RDD and should be considered in recurrent cases after prior surgical excision.

Gravitational wave peeps from EMRIs and their implication for LISA signal confusion noise

Scattering events around the center of massive galaxies will occasionally toss a stellar-mass compact object into an orbit around the massive black hole (MBH) at the center, beginning an extreme mass ratio inspiral (EMRI). The early stages of such a highly eccentric orbit are not likely to produce detectable gravitational waves (GWs), as the source will only be in a suitable frequency band briefly when it is close to periapsis during each long-period orbit. This repeated burst of emission, firmly in the millihertz band, is the GW peep. While a single peep is not likely to be detectable, if we consider an ensemble of such subthreshold sources, spread across the Universe, together they may produce an unresolvable background noise that could obscure sources otherwise detectable by the Laser Interferometer Space Antenna. Previous studies of the extreme mass ratio signal confusion background focused either on parabolic orbits near the MBH or events closer to merger. We seek to improve this characterization by implementing numerical kludge waveforms that can calculate highly eccentric orbits with relativistic effects. Our focus is on orbits at the point of capture that are farther away from the MBH. Here we present the waveforms and spectra of peeps generated from recent calculations of EMRIs/extreme mass ratio bursts capture parameters and discuss how these can be used to estimate the signal confusion noise generated by such events. We demonstrate the effects of changing the orbital parameters on the resulting spectra as well as showing direct comparisons to parabolic orbits and why the GW ‘peep’ needs to be studied further. The results of this study will be expanded upon in a further paper that aims to provide an update on the EMRI signal confusion noise problem.

The effect of thermal torques on AGN disc migration traps and gravitational wave populations

ABSTRACT Accretion discs in active galactic nuclei (AGNs) foster black hole (BH) formation, growth, and mergers. Stellar mass BHs migrate inwards under the influence of hydrodynamical torques unless they encounter a region where the torque flips sign. At these migration traps, BHs accumulate and merge via dynamical or gas-assisted interactions, producing high-frequency LIGO/Virgo/KAGRA (LVK) gravitational wave (GW) sources and potentially cutting off the supply of extreme mass ratio inspirals that would otherwise make low-frequency, LISA-band GWs. In this paper, we study the interplay between different types of migration torques, focusing especially on the ‘thermal torques’ generated by the thermal response of the AGN to embedded stellar-mass BHs that accrete through their own mini-discs. In contrast to previous work, we find that Type I torques cannot produce migration traps on their own, but thermal torques often do, particularly in low-mass AGN. The migration traps produced by thermal torques exist at much larger distances (∼103−5 gravitational radii) than do previously identified Type I traps, carrying implications for GW populations at multiple frequencies. Finally, we identify a bifurcation of AGN discs into two regimes: migration traps exist below a critical AGN luminosity, and do not at higher luminosities. This critical luminosity is fit as $\log _{10} L_{\rm AGN}^c = 45 {\!-\!} 0.32 \log _{10}{(\alpha /0.01)}$ where α is the Shakura–Sunyaev viscosity parameter, a range compatible with recent claims that LVK GWs are not preferentially associated with high-luminosity AGN.

From the grapevine to the glass: A wine metabolomics tale by FT-ICR-MS.

Wine is one of the most consumed beverages around the world. Its unique characteristics arise from numerous processes, from the selection of grapevine varieties and grapes, the effect of the terroir and geographical origin, through the biochemical process of fermentation by microorganisms, until its aging. All molecules found in wine define its chemical fingerprint and can be used to tell the story of its origin, production, authenticity and quality. Wine's chemical composition can be characterized using an untargeted metabolomics approach based on extreme resolution mass spectrometry. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is currently the most powerful analytical technique to analyse such complex sample, providing the most comprehensive analysis of the chemical fingerprint of wine.

Flickering pulsations in bright X-ray pulsars: the evidence of gravitationally lensed and eclipsed accretion column

ABSTRACT It is expected that the extreme mass accretion rate onto strongly magnetized neutron stars results in the appearance of accretion columns above the stellar surface. For a distant observer, rotation of a star results in periodic variations of X-ray flux. Because the mass accretion rate fluctuates around the average value, the pulse profiles are not stable and demonstrate fluctuations as well. In the case of bright X-ray pulsars, however, pulse fluctuations are not solely attributed to variations in the mass accretion rate. They are also influenced by the variable height of the columns, which is dependent on the mass accretion rate. This study delves into the process of pulse profile formation in bright X-ray pulsars, taking into account stochastic fluctuations in the mass accretion rate, the corresponding variations in accretion column geometry, and gravitational bending. Our analysis reveals that potential eclipses of accretion columns by a neutron star during their spin period should manifest specific features in pulse profile variability. Applying a novel pulse profile analysis technique, we successfully detect these features in the bright X-ray transient V 0332+53 at luminosities $\gtrsim 2\times 10^{38}\, {\rm erg\ \rm s^{-1}}$. This detection serves as compelling evidence for the eclipse of an accretion column by a neutron star. Detection of the eclipse places constraints on the relation between neutron star mass, radius, and accretion column height. Specifically, we can establish an upper limit on the accretion column height, which is crucial for refining theoretical models of extreme accretion.

Dynamics of Body Component Composition Indicators in Males During Studying at the Military Medical University

The study of anthropometric indicators and body composition of various categories of the population makes it possible to monitor physical development, conduct health assessments and timely development of preventive measures. The purpose of the study is to evaluate the dynamics of indicators of the component composition of the body of military university cadets during the training period from 1st to 6th year. Material and methods. 387 male cadets (the same persons) were examined during the period of their studies in 1-6 courses. The component composition of the body was studied using bioimpedance measurements. Results. It has been shown that during the first two courses of study (persons 17-18 years old) there is an increase in muscle mass of the trunk by 13.8%, muscle mass of the upper extremities - by 11.4% and lower extremities - by 6.1%, which is explained by the presence intense physical activity. Moreover, during the first year of study, a slight increase in the fat component of the body is determined (5.4%). In the third and fourth years of study, there is a stabilization and slowdown in the growth of the formed muscle and fat masses of the trunk and limbs, characteristic of the transition period from adolescence to adulthood. These trends continued to increase throughout the 5th year of study, but the level of basal metabolism did not change significantly throughout the study. In the 6th year, in relation to the time of admission to university, a general increase in the muscle component of the torso was established by 17.2%, muscle mass of the upper extremities - by 15.8%, and lower extremities - by 9.6%. Over 6 years of study, the fat content in the torso increased by 8.2%, the fat mass of the upper and lower extremities - by 7.5% and 8.0%, respectively, and the level of visceral fat increased by 9.3%. The vital volume of the lungs increased by 12.2% compared to the beginning of the 1st course. Conclusion. The above transformations are obviously due to the continued growth of a healthy organism. Reduced adaptive changes during the training period can be corrected by increasing physical activity, diet and caloric intake.

Search for Extreme Mass Ratio Inspirals Using Particle Swarm Optimization and Reduced Dimensionality Likelihoods

Extreme-mass-ratio inspirals (EMRIs) are significant observational targets for spaceborne gravitational wave detectors, namely, LISA, Taiji, and Tianqin, which involve the inspiral of stellar-mass compact objects into massive black holes (MBHs) with a mass range of approximately 104∼107M⊙. EMRIs are estimated to produce long-lived gravitational wave signals with more than 105 cycles before plunge, making them an ideal laboratory for exploring the strong-gravity properties of the spacetimes around the MBHs, stellar dynamics in galactic nuclei, and properties of the MBHs itself. However, the complexity of the waveform model, which involves the superposition of multiple harmonics, as well as the high-dimensional and large-volume parameter space, make the fully coherent search challenging. In our previous work, we proposed a 10-dimensional search using Particle Swarm Optimization (PSO) with local maximization over the three initial angles. In this study, we extend the search to an 8-dimensional PSO with local maximization over both the three initial angles and the angles of spin direction of the MBH, where the latter contribute a time-independent amplitude to the waveforms. Additionally, we propose a 7-dimensional PSO search by using a fiducial value for the initial orbital frequency and shifting the corresponding 8-dimensional Time Delay Interferometry responses until a certain lag returns the corresponding 8-dimensional log-likelihood ratio’s maximum. The reduced dimensionality likelihoods enable us to successfully search for EMRI signals with a duration of 0.5 years and signal-to-noise ratio of 50 within a wider search range than our previous study. However, the ranges used by both the LISA Data Challenge (LDC) and Mock LISA Data Challenge (MLDC) to generate their simulated signals are still wider than the those we currently employ in our direct searches. Consequently, we discuss further developments, such as using a hierarchical search to narrow down the search ranges of certain parameters and applying Graphics Processing Units to speed up the code. These advances aim to improve the efficiency, accuracy, and generality of the EMRI search algorithm.

Reduced Muscle Mass and Muscle Quality in Patients with Intermittent Claudication due to Peripheral Artery Disease

ObjectivePeripheral arterial disease (PAD) is associated with reduced muscle mass and quality, but the effects of leg ischemia caused by PAD on muscle quality remain poorly understood. The purpose of this study was to evaluate leg muscle mass and muscle quality in patients with intermittent claudication due to PAD using bioelectrical impedance analysis (BIA). MethodsOne hundred forty-one patients with intermittent claudication due to PAD who visited Tokyo Medical University Hospital from April 2019 to April 2020 were retrospectively analyzed. Leg ischemia was assessed using ankle-brachial index (ABI). The skeletal muscle mass (SMM) assessed leg muscle mass, while the phase angle (PhA) assessed leg muscle quality using BIA. ResultsA total of 282 legs in 141 patients were included in the analysis. Leg PhA and SMM showed a decreasing trend according to the severity of leg ischemia (borderline/no ischemia: 2.80 ± 0.50 kg/m2, 4.38 ± 0.94°; mild ischemia: 2.83 ± 0.49 kg/m2, 4.33 ± 1.03°; moderate/severe ischemia: 2.50 ± 0.40 kg/m2, 3.89 ± 0. 88°; p<0.001 and p=0.020, respectively). The ABI was moderately correlated with leg SMM (B=0.347, β=0.134, p<0.001) and leg PhA (B=0.577, β=0.111, p=0.013) after adjustment for all significant covariates. Leg PhA was moderately correlated with leg SMM (r = 0.318, p < 0.001). ConclusionsLeg ischemia, especially when moderate or severe, has an adverse effect on both muscle mass and quality in the lower extremities and is associated with skeletal muscle myopathy.

A Candidate Supermassive Black Hole in a Gravitationally Lensed Galaxy at Z ≈ 10

While supermassive black holes (SMBHs) are widely observed in the nearby and distant Universe, their origin remains debated with two viable formation scenarios with light and heavy seeds. In the light seeding model, the seed of the first SMBHs form from the collapse of massive stars with masses of 10–100 M ⊙, while the heavy seeding model posits the formation of 104–5 M ⊙ seeds from direct collapse. The detection of SMBHs at redshifts z ≳ 10, edging closer to their formation epoch, provides critical observational discrimination between these scenarios. Here, we focus on the JWST-detected galaxy, GHZ 9, at z ≈ 10 that is lensed by the foreground cluster, A2744. Based on 2.1 Ms deep Chandra observations, we detect a candidate X-ray active galactic nucleus (AGN), which is spatially coincident with the high-redshift galaxy, GHZ 9. The SMBH candidate is inferred to have a bolometric luminosity of (1.0−0.4+0.5)×1046ergs−1 , which corresponds to a black hole (BH) mass of (8.0−3.2+3.7)×107M⊙ assuming Eddington-limited accretion. This extreme mass at such an early cosmic epoch suggests the heavy seed origin for this BH candidate. Based on the Chandra and JWST discoveries of extremely high-redshift quasars, we have constructed the first simple AGN luminosity function extending to z ≈ 10. Comparison of this luminosity function with theoretical models indicates an overabundant z ≈ 10 SMBH population, consistent with a higher-than-expected seed formation efficiency.

Cosmic hide and seek: The volumetric rate of X-ray quasi-periodic eruptions

Multiwavelength extragalactic nuclear transients, particularly those detectable as multi-messengers, are among the primary drivers for the next-generation observatories. X-ray quasi-periodic eruptions (QPEs) are the most recent and perhaps most peculiar addition to this group. Here, we report a first estimate of the volumetric rate of QPEs based on the first four discoveries with the eROSITA X-ray telescope onboard the Spectrum Roentgen Gamma observatory. Under the assumption, supported by a suite of simulated light curves, that these four sources sample the intrinsic population somewhat homogeneously, we correct for their detection efficiency and compute a QPE abundance of Rvol = 0.60−0.43+4.73 × 10−6 Mpc−3 above an intrinsic average log L0.5−2.0 keVpeak &gt; 41.7. Since the exact lifetime of QPEs (τlife) is currently not better defined than between a few years or few decades, we convert this to a formation rate of ℛvol/τlife ≈ 0.6 × 10−7(τlife/10 yr)−1 Mpc−3 yr−1. As a comparison, this value is a factor ∼10 τlife times smaller than the formation rate of tidal disruption events. The origin of QPEs is still debated, although lately most models suggest that they are the electromagnetic counterpart of extreme mass ratio inspirals (EMRIs). In this scenario, the QPE rate would thus be the first ever constraint (i.e. a lower limit) to the EMRI rate from observations alone. Future discoveries of QPEs and advances in their theoretical modeling will consolidate or rule out their use for constraining the number of EMRIs detectable by the LISA mission.

Tracing the evolution of short-period binaries with super-synchronous fast rotators

Context. The initial distribution of rotational velocities of stars is still poorly known, and how the stellar spin evolves from birth to the various end points of stellar evolution is an actively debated topic. Binary interactions are often invoked to explain the existence of extremely fast-rotating stars (vsin i ≳ 200 km s−1). The primary mechanisms through which binaries can spin up stars are tidal interactions, mass transfer, and possibly mergers. However, fast rotation could also be primordial, that is, a result of the star formation process. To evaluate these scenarios, we investigated in detail the evolution of three known fast-rotating stars in short-period spectroscopic and eclipsing binaries, namely HD 25631, HD 191495, and HD 46485, with primaries of masses of 7, 15, and 24 M⊙, respectively, with companions of ∼1 M⊙ and orbital periods of less than 7 days. These systems belong to a recently identified class of binaries with extreme mass ratios, whose evolutionary origin is still poorly understood. Aims. We evaluated in detail three scenarios that could explain the fast rotation observed in these binaries: it could be primordial, a product of mass transfer, or the result of a merger within an originally triple system. We also discuss the future evolution of these systems to shed light on the impact of fast rotation on binary products. Methods. We computed grids of single and binary MESA models varying tidal forces and initial binary architectures to investigate the evolution and reproduce observational properties of these systems. When considering the triple scenario, we determined the region of parameter space compatible with the observed binaries and used a publicly available machine-learning model to determine the dynamical stability of the triple system. Results. We find that, because of the extreme mass-ratio between binary components, tides have a limited impact, regardless of the prescription used, and that the observed short orbital periods are at odds with post-mass-transfer scenarios. We also find that the overwhelming majority of triple systems compatible with the observed binaries are dynamically unstable and would be disrupted within years of formation, forcing a hypothetical merger to happen so close to a zero-age main-sequence that it could be considered part of the star formation process. Conclusions. The most likely scenario to form such young, rapidly rotating, and short-period binaries is primordial rotation, implying that the observed binaries are pre-interaction ones. Our simulations further indicate that such systems will subsequently go through a common envelope and likely merge. These binaries show that the initial spin distribution of massive stars can have a wide range of rotational velocities.

Impacts of gravitational-wave background from supermassive black hole binaries on the detection of compact binaries by LISA* *Supported by the NSFC (12250010, 11991052) and Key Research Program of Frontier Sciences, CAS, (ZDBS-LY-7009)

In the frequency band of the Laser Interferometer Space Antenna (LISA), extensive research has been conducted on the impact of foreground confusion noise generated by galactic binaries within the Milky Way Galaxy. Additionally, recent evidence of a stochastic signal, announced by the NANOGrav, EPTA, PPTA, CPTA, and InPTA, indicates that the stochastic gravitational-wave background (SGWB) generated by supermassive black hole binaries (SMBHBs) can contribute strong background noise within the LISA band. Given the presence of such strong noise, it is expected to have significant impacts on LISA's scientific missions. In this study, we investigate the impacts of the SGWB generated by SMBHBs on the detection of individual massive black hole binaries, verified galactic binaries, and extreme mass ratio inspirals in the context of LISA. We find it essential to resolve and eliminate the excess noise from the SGWB to guarantee the success of LISA's missions.

Quadriceps femoris muscle ultrasound in sarcoidosis: an observational case-control study.

Although loss of muscle mass may be associated with general weakness, intolerance to physical activity and fatigue, it is underestimated and poorly understood in patients with sarcoidosis. To compare the quadriceps femoris muscle (QFM) thickness measured by ultrasonography (US) between the female patients with sarcoidosis and controls, secondly to assess the correlation between the muscle strength, fatigue and QFM thickness. Observational, case-control study. Physical Medicine and Rehabilitation Department of a University Hospital. Thirty-one women with sarcoidosis and 27 healthy volunteers were included in the study. The participants were evaluated for the following outcomes: 1) handgrip strength; 2) QFM thickness measured using US; and 3) sonographic thigh adjustment ratio (STAR). The sarcoidosis group was also evaluated with the 30-second chair stand test (30s-CST) and Fatigue Severity Scale (FSS). The QFM thickness and STAR values of the patients with sarcoidosis were significantly lower than those of the controls (P=0.0001). However, no statistically significant difference was observed between the handgrip strengths of the groups (P=0.581). There was no statistically significant correlation between the STAR values and handgrip strength in the sarcoidosis group; however, there was a significant positive correlation between the STAR values and 30s-CST (r=0.467, P=0.008). Loss of muscle mass is one of the musculoskeletal conditions in patients with sarcoidosis that may be associated with nonspecific symptoms, such as general debility, intolerance to physical activity, and fatigue. In the present study, no difference was observed in hand grip strength between the groups, while we found that QFM thickness was affected in patients with sarcoidosis when compared to the controls. The ultrasonographic QFM evaluation seems to be an innovative tool which may be used at all stages of sarcoidosis patient follow-up. The grip strength is a commonly used test to detect muscle weakness, but onset of a decrease in muscle mass in the lower extremities may occur earlier. Considering the increased burden of musculoskeletal problems in this population, performing 30s-CST and sonographic QFM thickness is practical methods to identify risky patients.

Airy worlds or barren rocks? On the survivability of secondary atmospheres around the TRAPPIST-1 planets

Context. The James Webb Space Telescope is currently at the forefront of the search for atmospheres of exoplanets. However, the observation of atmospheres of Earth-like planets pushes the limits of the instruments, and often, multiple observations must be combined. As with most instruments, telescope time is unfortunately extremely limited. Over the course of cycle 1, approximately 100 hours have been dedicated to the TRAPPIST-1 planets. This system is therefore studied in unusually great detail. However, the first two sets of observations of the innermost two planets show that these planets most likely lack a thick atmosphere. The question therefore arises whether terrestrial planets around M stars have atmospheres or do not have atmospheres at all. Aims. We aim to determine the atmospheric survivability of the TRAPPIST-1 planets by modelling the response of the upper atmosphere to incoming stellar high-energy radiation. Through this case study, we also aim to learn more about rocky planet atmospheres in the habitable zone around low-mass M dwarfs. Methods. We simulated the upper atmospheres of the TRAPPIST-1 planets using the Kompot code, which is a self-consistent thermo-chemical code. Specifically, we studied the atmospheric mass loss due to Jeans escape induced by stellar high-energy radiation. This was achieved through a grid of models that account for the differences in planetary properties and irradiances of the TRAPPIST-1 planets, as well as different atmospheric properties. This grid allows for the explorations of the different factors influencing atmospheric loss. Results. The present-day irradiance of the TRAPPIST-1 planets would lead to the loss of an Earth’s atmosphere within just some hundreds of million years. When we take into account the much more active early stages of a low-mass M dwarf, the planets undergo a period of even more extreme mass loss, regardless of planetary mass or atmospheric composition. Conclusions. The losses calculated in this work indicate that it is unlikely that any significant atmosphere could survive for any extended amount of time around any of the TRAPPIST-1 planets based on present-day irradiance levels. The assumptions used here allow us to generalise the results, and we conclude that the results tentatively indicate that this conclusion applies to all Earth-like planets in the habitable zones of low-mass M dwarfs.

Effective Field Theory for Extreme Mass Ratio Binaries.

We derive an effective field theory describing a pair of gravitationally interacting point particles in an expansion in their mass ratio, also known as the self-force (SF) expansion. The 0SF dynamics are trivially obtained to all orders in Newton's constant by the geodesic motion of the light body in a Schwarzschild background encoding the gravitational field of the heavy body. The corrections at 1SF and higher are generated by perturbations about this configuration-that is, the geodesic deviation of the light body and the fluctuation graviton-but crucially supplemented by an operator describing the recoil of the heavy body as it interacts with the smaller companion. Using this formalism we compute new results at third post-Minkowskian order for the conservative dynamics of a system of gravitationally interacting massive particles coupled to a set of additional scalar and vector fields.