Search

Young, low-mass brown dwarfs orbiting early-type stars, with low mass ratios ( q ≲ 0.01), appear to be intrinsically rare and present a formation dilemma: could a handful of these objects be the highest-mass outcomes of “planetary” formation channels (bottom up within a protoplanetary disk), or are they more representative of the lowest-mass “failed binaries” (formed via disk fragmentation or core fragmentation)? Additionally, their orbits can yield model-independent dynamical masses, and when paired with wide wavelength coverage and accurate system age estimates, can constrain evolutionary models in a regime where the models have a wide dispersion depending on the initial conditions. We present new interferometric observations of the 16 Myr substellar companion HD 136164 Ab (HIP 75056 Ab) made with the Very Large Telescope Interferometer (VLTI)/GRAVITY and an updated orbit fit including proper motion measurements from the Hipparcos–Gaia Catalog of Accelerations. We estimate a dynamical mass of 35 ± 10 M _J ( q ∼ 0.02), making HD 136164 Ab the youngest substellar companion with a dynamical mass estimate. The new mass and newly constrained orbital eccentricity ( e = 0.44 ± 0.03) and separation (22.5 ± 1 au) could indicate that the companion formed via the low-mass tail of the initial mass function. Our atmospheric fit to a SPHINX M-dwarf model grid suggests a subsolar C/O ratio of 0.45 and 3 × solar metallicity, which could indicate formation in a circumstellar disk via disk fragmentation. Either way, the revised mass estimate likely excludes bottom-up formation via core accretion in a circumstellar disk. HD 136164 Ab joins a select group of young substellar objects with dynamical mass estimates; epoch astrometry from future Gaia data releases will constrain the dynamical mass of this crucial object further.

Giant exoplanets have been directly imaged over orders of magnitude of orbital separations, prompting theoretical and observational investigations of their formation pathways. In this paper, we present new VLTI/GRAVITY astrometric data of HIP 65426 b, a cold, giant exoplanet which is a particular challenge for most formation theories at a projected separation of 92 au from its primary. Leveraging GRAVITY’s astrometric precision, we present an updated eccentricity posterior that disfavors large eccentricities. The eccentricity posterior is still prior dependent, and we extensively interpret and discuss the limits of the posterior constraints presented here. We also perform updated spectral comparisons with self-consistent forward-modeled spectra, finding a best-fit ExoREM model with solar metallicity and C/O = 0.6. An important caveat is that it is difficult to estimate robust errors on these values, which are subject to interpolation errors as well as potentially missing model physics. Taken together, the orbital and atmospheric constraints paint a preliminary picture of formation inconsistent with scattering after disk dispersal. Further work is needed to validate this interpretation. Analysis code used to perform this work is available on GitHub: https://github.com/sblunt/hip65426 .

Tension remains between the observed and modeled properties of substellar objects, but objects in binary orbits, with known dynamical masses, can provide a way forward. HD 72946 B is a recently imaged brown dwarf companion to a nearby, solar-type star. We achieve ∼100 μ as relative astrometry of HD 72946 B in the K band using VLTI/GRAVITY, unprecedented for a benchmark brown dwarf. We fit an ensemble of measurements of the orbit using orbitize! and derive a strong dynamical mass constraint M _B = 69.5 ± 0.5 M _Jup assuming a strong prior on the host star mass M _A = 0.97 ± 0.01 M _⊙ from an updated stellar analysis. We fit the spectrum of the companion to a grid of self-consistent BT-Settl-CIFIST model atmospheres, and perform atmospheric retrievals using petitRADTRANS . A dynamical mass prior only marginally influences the sampled distribution of effective temperature, but has a large influence on the surface gravity and radius, as expected. The dynamical mass alone does not strongly influence retrieved pressure–temperature or cloud parameters within our current retrieval setup. Independently of the cloud prescription and prior assumptions, we find agreement within ±2 σ between the C/O of the host (0.52 ± 0.05) and brown dwarf (0.43–0.63), as expected from a molecular cloud collapse formation scenario, but our retrieved metallicities are implausibly high (0.6–0.8) in light of the excellent agreement of the data with the solar-abundance model grid. Future work on our retrieval framework will seek to resolve this tension. Additional study of low surface gravity objects is necessary to assess the influence of a dynamical mass prior on atmospheric analysis.

Introduction A growing body of evidence has shown the association between autoimmune thyroiditis and mental illness (Rege et al. AUS N J S Psychiatry 2013; 300 141-154). Identifying the neuropsychiatric features associated with thyroid antibody positivity could have significant implications for diagnostic and therapeutic strategies. However, the link between anti-thyroid antibodies and precise underlying pathophysiology requires future research. Objectives The aim of the present study was to conduct a retrospective evolution in patients diagnosed with schizophrenia spectrum disorder and affective disorder who were screened for anti-thyroid antibodies at the time of their hospitalization and to investigate neuropsychiatric features of anti-thyroid antibody-positive patients. Methods A total of 143 inpatients diagnosed with schizophrenia spectrum disorders and affective disorders between 2021 and 2023 were screened for anti-thyroid antibodies such as thyroid peroxidase (TPO) and thyroglobulin (TG). All patients were women. In order to elucidate the subsequent neuropsychiatric clinical features of individuals with positive anti-thyroid antibodies, the retrospective examination was conducted based on Neuropsychiatric Invetory-Q (NPI-Q) and DSM-V diagnostic criteria utilized at the time of hospitalization. Results The main age of the patients was 48.2 (SD 10.4). A total of 143 inpatients with schizophrenia spectrum disorders and affective disorders were screened for anti-thyroid antibodies at the time of their hospitalizations. %23.1 (n=33) tested positive for at least one of the anti-TG or anti-TPO. All patients were euthyroid. The neuropsychiatric diagnoses are shown in Table 1. The most common neuropsychiatric features assessed by NPI-Q are shown in Table 2. 12.1% (n=4) of all patients were treated with IV steroid Pulse therapy. Table 1. Neuropsychiatric syndrom-level diagnostic patterns according to DSM-V Patients with positive thyroid autoantibodies(n=33) Manic syndrome 10 (30.3%) Psychotic Syndrome 19 ( 57.6%) Depression syndrome 5 (15.2%) Catatonia 10 (30.3%) Exited 6 (18.2%) Stuporus 2 (6.1%) Fluctuating 2 (6.1%) Table 2. The most common clusters of Neuropsychiatric features NPI-Q Positive Thyroid Autoantibodies(n=33) Delusion 15 (45.4%) Agitation/Aggression 14 (42.4%) Irrıtability 14 (42.4%) Motor abnormality 14 (42.4%) Sleep disorder 15 (45.4%) Appetite/Eating 14 (42.4%) Conclusions In particular, in a subset of schizophrenia spectrum disorder or affective disorder patients with positive anti-thyroid antibodies may indicate autoimmunity, especially in cases where catatonic symptoms dominate the clinical presentation. Disclosure of Interest None Declared

"nBackground: The association between maternal smoking and poor pregnancy outcome, which is well established in medi­cal literature, has also been corroborated by the results of this study conducted in a Turkish hospital. Our objective was to investi­gate the effects of cigarette smoking during pregnancy on infant head circumference, height, weight, and body mass in­dex (BMI)."nMethods: In this retrospective study, the data was collected from the Medical Live Birth Registry in a maternity hospital with the largest capacity of births in a city of northwest Turkey during 2002."nResults: We found that 16.4% (1040/6332) of mothers investigated had smoked during their pregnancy, with a mean of 5 ciga­rettes per day. Head circumference, height, weight and BMI values of male infants whose mothers smoked were found to be less than those of infants whose mothers did not smoke (P> 0.05, for each one). Head circumference, height, weight and BMI values of female infants whose mothers smoked were less than those whose mothers did not smoke (P> 0.05, P< 0.01, P< 0.05 and P> 0.05, respectively). According to analysis of variance, infant head circumferences, heights and weights in all infants decreased as the rate of the mother's smoking increased (P> 0.05, P< 0.001 and P> 0.05, respec­tively)."nConclusions: The results support that maternal smoking during pregnancy was associated with a linear reduction of height meas­urement, and the infants appeared to be more susceptible to the growth retarding effects of cigarette smoking on height. Thus, if cessation-of-smoking programs are initiated before conception, many of the harmful effects of smoking on fe­tal growth might be prevented.

Background: The association between maternal smoking and poor pregnancy outcome, which is well established in medi­cal literature, has also been corroborated by the results of this study conducted in a Turkish hospital. Our objective was to investi­gate the effects of cigarette smoking during pregnancy on infant head circumference, height, weight, and body mass in­dex (BMI). Methods: In this retrospective study, the data was collected from the Medical Live Birth Registry in a maternity hospital with the largest capacity of births in a city of northwest Turkey during 2002. Results: We found that 16.4% (1040/6332) of mothers investigated had smoked during their pregnancy, with a mean of 5 ciga­rettes per day. Head circumference, height, weight and BMI values of male infants whose mothers smoked were found to be less than those of infants whose mothers did not smoke (P> 0.05, for each one). Head circumference, height, weight and BMI values of female infants whose mothers smoked were less than those whose mothers did not smoke (P> 0.05, P< 0.01, P< 0.05 and P> 0.05, respectively). According to analysis of variance, infant head circumferences, heights and weights in all infants decreased as the rate of the mother's smoking increased (P> 0.05, P< 0.001 and P> 0.05, respec­tively). Conclusions: The results support that maternal smoking during pregnancy was associated with a linear reduction of height meas­urement, and the infants appeared to be more susceptible to the growth retarding effects of cigarette smoking on height. Thus, if cessation-of-smoking programs are initiated before conception, many of the harmful effects of smoking on fe­tal growth might be prevented.