Astronomy & Astrophysics最新文献

{"title":"Doppler velocity oscillations in an Hα network rosette","authors":"Jongchul Chae, Eun-Kyung Lim, Juhyung Kang, Kyoung-Sun Lee, Maria S. Madjarska","doi":"10.1051/0004-6361/202555021","DOIUrl":"https://doi.org/10.1051/0004-6361/202555021","url":null,"abstract":"Magnetic flux tubes such as sunspots play the role of channels through which magnetohydrodynamic waves carry mechanical energy from the solar interior to the atmosphere. We investigate the spatial distribution of Doppler velocity oscillations in the chromospheric network rosette, a supposed quiet Sun miniature of a sunspot, by analyzing H<i>α<i/> line spectral data taken with the Fast Imaging Solar Spectrograph of the Goode Solar Telescope. The rosette consists of two regions: a central region displaying H<i>α<i/> emission and a fibril region displaying H<i>α<i/> absorption. We have categorized the observed velocity oscillations into three groups depending on location and period. Group I oscillations with periods from 3 to 6 min occur in the central region, group II oscillations with periods from 6 to 20 min in the inner parts of the fibril region, and group III oscillations with periods shorter than 3 min in the outermost parts of the fibril region. We discuss the probable physical origin of oscillations of each group. Our results suggest that the rosette is similar to a sunspot in morphology and oscillation properties, but there exist differences as well.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"236 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Virial quantities of galaxy clusters from extrapolating strong-lensing mass profiles","authors":"Enrico Maraboli, Claudio Grillo, Pietro Bergamini, Carlo Giocoli","doi":"10.1051/0004-6361/202554495","DOIUrl":"https://doi.org/10.1051/0004-6361/202554495","url":null,"abstract":"We study the radial total mass profiles of nine massive galaxy clusters (<i>M<i/><sub>200c<sub/> > 5 × 10<sup>14<sup/> M<sub>⊙<sub/>) in the redshift range 0.2 < <i>z<i/> < 0.9. These clusters were observed as part of the CLASH, HFF, BUFFALO, and CLASH-VLT programs, which provided high-quality photometric and spectroscopic data. Additional high-resolution spectroscopic data were obtained with the integral-field spectrograph MUSE at the Very Large Telescope. Our research takes advantage of strong-lensing analyses that rely on deep panchromatic and spectroscopic measurements. From these data, we measure the projected total mass profiles of each galaxy cluster in our sample. We fit these mass profiles with simple one-component spherically symmetric mass models including the Navarro–Frenk–White (NFW) nonsingular isothermal sphere, dual pseudo-isothermal ellipsoidal, a beta model, and Hernquist profiles. We performed a Bayesian analysis to sample the posterior probability distributions of the free parameters of the models. We find that the NFW, Hernquist, and beta models are the most suitable profiles for fitting the measured projected total mass profiles of the clusters. Moreover, we tested the robustness of our results by changing the region in which we performed the fits: We slightly modified the center of the projected mass profiles and the radial range of the region. We employed the results obtained with the Hernquist profile to compare our total mass estimates ( ) with the <i>M<i/><sub>200c<sub/> values from weak-lensing studies. Through this analysis, we found scaling relations between and <i>M<i/><sub>200c<sub/> and a value of the scale radius, <i>r<i/><sub>S<sub/>, and <i>R<i/><sub>200c<sub/>. Interestingly, we also found that the <i>M<i/><sub>200c<sub/> values we obtained by extrapolating the total mass profiles we fit are very close to the weak-lensing results. This feature can be exploited in future studies of clusters and cosmology because it provides an easy way to infer the virial masses of clusters.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"37 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of pure warm-hot intergalactic medium emission from a 7.2 Mpc long filament in the Shapley supercluster using X-ray spectroscopy","authors":"K. Migkas, F. Pacaud, T. Tuominen, N. Aghanim","doi":"10.1051/0004-6361/202554944","DOIUrl":"https://doi.org/10.1051/0004-6361/202554944","url":null,"abstract":"A significant fraction of the local Universe baryonic content still remains undetected. Cosmological simulations indicate that most of the missing baryons reside in cosmic filaments in the form of warm-hot intergalactic medium (WHIM). The latter shows low surface brightness and soft X-ray emission, making it challenging to detect. Until now, X-ray WHIM emission has been detected only in very few individual filaments, whereas in even fewer filaments WHIM was spectroscopically analyzed. The Suzaku X-ray telescope is ideal for studying X-ray WHIM emission from filaments because of its low instrumental background. We used four Suzaku pointings to study the WHIM emission of a filament in the Shapley supercluster, connecting the galaxy cluster pairs A3530/32 and A3528-N/S. We additionally employ XMM-Newton observations to robustly account for point sources in the filament, which Suzaku fails to detect because of its poor angular resolution, and to fully characterize the neighboring clusters and their signal contamination to the filament region. We report the direct imaging and spectroscopic detection of extended thermal WHIM emission from this single filament. Our imaging analysis confirms the existence of (21±3)% additional X-ray emission throughout the filament compared to the sky background at a 6.1<i>σ<i/> level. We constrain the filament gas temperature, electron density, and baryon overdensity to be <i>k<i/><sub>B<sub/><i>T<i/>≈(0.8−1.1) keV, <i>n<i/><sub>e<sub/>≈10<sup>−5<sup/> cm<sup>−3<sup/>, and <i>δ<i/><sub>b<sub/>≈(30−40), respectively, at a >3<i>σ<i/> detection level, in agreement with cosmological simulations for the first time for a single filament. Independently of the X-ray analysis, we also identify a spectroscopic galaxy overdensity throughout the filament using the Shapley Supercluster velocity Database and constrain the filament's 3D length to be 7.2 Mpc at a 53° angle with the plane of the sky. Overall, this is the first X-ray spectroscopic detection of pure WHIM emission from an individual, pristine filament without significant contamination from unresolved point sources and gas clumps.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"147 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shared properties of merger-driven long-duration gamma-ray bursts","authors":"Yacheng Kang, Jin-Ping Zhu, Yu-Han Yang, Ziming Wang, Eleonora Troja, Bing Zhang, Lijing Shao, Zhuo Li","doi":"10.1051/0004-6361/202554448","DOIUrl":"https://doi.org/10.1051/0004-6361/202554448","url":null,"abstract":"<i>Context.<i/> The recent detections of bright optical/infrared kilonova signals following two long-duration gamma-ray bursts (LGRBs), GRB 211211A and GRB 230307A, have significantly challenged the traditional classification of GRBs. These merger-driven LGRBs may represent a distinct GRB population, sparking interest in their progenitors and central engines.<i>Aims.<i/> Traditional GRB classification methods often struggle to distinguish merger-driven LGRBs from traditional merger-driven short-duration GRBs resulting from compact object mergers and from collapse-driven LGRBs produced by massive stars. We thus aim to explore the shared properties in terms of hardness, energy, and duration among observed merger-driven LGRB events, thereby identifying their observed differences from the traditional GRB population.<i>Methods.<i/> We collected a sample of merger-driven LGRBs with known redshifts, including observed information on their main emission (ME) and whole emission (WE) phases. Treating ME and WE properties as two independent sets of information, we applied several GRB classification methodologies to explore their potential shared properties.<i>Results.<i/> Using the phenomenologically defined energy-hardness (<i>EH<i/>) parameter, characterized by the intrinsic hardness and energy of GRBs, and the duration of GRBs, we identified a probable universal linear correlation across merger-driven LGRBs that holds regardless of whether their ME or WE phases are considered.<i>Conclusions.<i/> We propose that such shared properties of merger-driven LGRBs are unlikely to arise from the low-redshift selection effect, and they become particularly intriguing when compared with the relatively weak correlations or lack of correlation observed in traditional merger-driven short-duration GRBs (with or without extended emissions) and collapse-driven LGRBs. Our newly proposed correlation highlights the necessity for further investigation into the observations of merger-driven LGRBs and the physical mechanisms underlying the empirical correlation.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"16 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polarization of light from fast-rotating Wolf–Rayet stars: Monte Carlo simulations compared to the analytical formula","authors":"S. Abdellaoui, J. Krtička, B. Kubátová, P. Kurfürst","doi":"10.1051/0004-6361/202553921","DOIUrl":"https://doi.org/10.1051/0004-6361/202553921","url":null,"abstract":"<i>Context<i/>. Fast-rotating Wolf–Rayet (WR) stars are potential progenitors of long gamma-ray bursts, but observational verification is challenging. Spectral lines from their expanding stellar wind obscure accurate rotational velocity measurements. Intrinsic polarization from wind rotation may help to determine rotational speeds. However, this procedure requires precise wind models.<i>Aims<i/>. Our study aims to investigate the intrinsic polarization due to the rotational distortion of WR winds considering multiplescattering of photons and compare it to a single-scattering model, in which we use an analytical expression of the polarization.<i>Methods<i/>. We studied the polarization signatures resulting from the prolate structure of rotating winds of two WR stars using a 3D Monte Carlo radiative transfer code Hyperion. We estimated the intrinsic polarization resulting from multiple-scattering in WR winds for different rotational velocities, inclination angles, and mass-loss rates.<i>Results<i/>. Our results indicate that at a rotation rate of less than 50% of the critical rate, the intrinsic polarization from multiplescattering is close to that of a single-scattering model. However, at higher rotation velocities, the polarization from multiple-scattering increases with inclination up to 40°, while it decreases for inclinations higher than about 60°. This dependence is inconsistent with the single-scattering model. We also discuss the effect of the mass-loss rate on the polarization and find that the polarization changes linearly with the mass-loss rate. However, it is important to note that the relationship between polarization and mass-loss rate may vary for different types of stars.<i>Conclusions<i/>. The results have implications for future studies of stellar winds and mass loss and may help to improve our understanding of the complex environments of massive stars. Our research offers valuable information on the complex polarization patterns observed in stellar winds, emphasizing the significance of accounting for the influence of multiple-scattering when interpreting observations.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"100 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling helium in exoplanet atmospheres. A revised network with photoelectron-driven processes","authors":"A. García Muñoz","doi":"10.1051/0004-6361/202555145","DOIUrl":"https://doi.org/10.1051/0004-6361/202555145","url":null,"abstract":"<i>Context<i/>. The He I line at 1.08 μm is a valuable tracer of atmospheric escape in exoplanet atmospheres.<i>Aims<i/>. We expand past networks used to predict the absorbing He(2<sup>3<sup/>S) by including, firstly, processes that involve H<sub>2<sub/> and some molecular ions, and secondly, the interaction of photoelectrons with the atmosphere.<i>Methods<i/>. We survey the literature on the chemical-collisional-radiative processes that govern the production-loss of He(2<sup>3<sup/>S). We simulate the atmospheric outflow from the Neptune-sized GJ 436 b by coupling a hydrodynamic model that solves the bulk properties of the gas and a Monte Carlo model that tracks the energy degradation of the photoelectrons.<i>Results<i/>. We identify Penning ionization of H as a key He(2<sup>3<sup/>S) loss process at GJ 436 b and update its rate coefficient to a value consistent with the most recent available cross sections. The update significantly affects the predicted strength of the He I line. For GJ 436 b, photoelectron-driven processes (mainly ionization and excitation) modify the He(2<sup>3<sup/>S) population in layers too deep to affect the in-transit spectrum. The situation might be different for other atmospheres though. The spectral energy distribution of the host star GJ 436 has a strong effect on the predicted in-transit signal. The published nondetections of the He I line for GJ 436 b are reasonably consistent with our model predictions for a solar-metallicity atmosphere when the model adopts a recently proposed spectral energy distribution for the star.<i>Conclusions<i/>. The interpretation of the He I line at 1.08 μm is model dependent. Our revised network provides a general framework for extracting more robust conclusions from measurements of this line, especially in atmospheres where H<sub>2<sub/> remains abundant to high altitudes. We will explore additional, previously ignored processes in future work.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"48 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SN 2023ixf: Interaction signatures in the spectrum at 445 days","authors":"Gastón Folatelli, Lucía Ferrari, Keila Ertini, Hanindyo Kuncarayakti, Keiichi Maeda","doi":"10.1051/0004-6361/202554128","DOIUrl":"https://doi.org/10.1051/0004-6361/202554128","url":null,"abstract":"<i>Context.<i/> SN 2023ixf is one of the nearest and brightest Type II supernovae (SNe) of the past decades. Its proximity and extremely early discovery have enabled a large number of studies based on extensive observations throughout the electromagnetic spectrum. A rich set of pre-explosion data provided important insight into the properties of the progenitor star. There has been, however, a wide range of estimated initial masses of 9–22 M<sub>⊙<sub/>. Early monitoring of the SN also showed the presence of a dense circumstellar material (CSM) structure near the star (≲10<sup>15<sup/> cm), which was probably expelled in the last years prior to the explosion. At farther distances, there have been indications of a drop in the CSM density. These extended CSM structures can be further probed with late-time observations during the nebular phase.<i>Aims.<i/> We monitored the spectroscopic evolution of SN 2023ixf at late phases with the aim of characterizing the progenitor properties. The observations also serve to search for indications of ejecta–CSM interaction that may shed light on the mass-loss processes during the final stages of evolution of the progenitor star.<i>Methods.<i/> This study is based on a nebular spectrum obtained with GMOS at the Gemini North Telescope 445 days after explosion. The SN evolution was analyzed in comparison with a previous spectrum at an age of 259 days. The 445 d spectrum was further compared with those of similar SNe II and with synthetic radiation-transfer nebular spectra. Line profiles were used to determine properties of the emitting regions. [O I] and [Ca II] line fluxes were used to derive an estimate of the progenitor mass at birth.<i>Results.<i/> The 445 d spectrum exhibits a dramatic evolution with signs of ejecta–CSM interaction. The H<i>α<i/> profile shows a complex profile that can be separated into a boxy component, possibly arising from the interaction with a CSM shell and a centrally peaked component that may be due to the radioactive-powered SN ejecta. The CSM shell would be located at a distance of ∼10<sup>16<sup/> cm from the progenitor, and it may be associated with mass loss occurring up until ≈500−1000 years before the explosion. Similar interaction signatures have been detected in other SNe II, although for events with standard plateau durations, this occurred later than 600–700 days. SN 2023ixf appears to belong to a group of SNe II with short plateaus or linear light curves that develop interaction features before ≈500 days. Other lines, such as those from [O I] and [Ca II], appear to be unaffected by the CSM interaction. This allowed us to estimate an initial progenitor mass, which falls in the relatively low range of 10–15 M<sub>⊙<sub/>.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"70 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase-space distortion as a key to unraveling galactic bar buckling","authors":"Viktor D. Zozulia, Natalia Ya. Sotnikova, Anton A. Smirnov","doi":"10.1051/0004-6361/202554837","DOIUrl":"https://doi.org/10.1051/0004-6361/202554837","url":null,"abstract":"For the first time, we investigate the resonant structure of <i>N<i/>-body galactic bar at the stage of buckling using action-angle variables. We studied the evolution of vertical actions (<i>J<i/><sub><i>z<i/><sub/>) and angles associated with vertical resonance (<i>θ<i/><sub>res<sub/> = <i>θ<i/><sub><i>z<i/><sub/> − <i>θ<i/><sub>R<sub/>) for all orbits in the bar. For this purpose, we divided the orbits into types according to the behavior (libration or circulation) of their resonant angle with respect to fixed points <i>θ<i/><sub>res<sub/> = 0 and <i>π<i/> (vertical resonance). We show that during buckling, flat bar orbits circulating with increasing <i>θ<i/><sub>res<sub/> transformed into banana-shaped librating orbits (resonant capture) or circulating orbits with decreasing <i>θ<i/><sub>res<sub/> (resonant heating). The orbital transformation is accompanied by an increase in <i>J<i/><sub><i>z<i/><sub/> and the formation of a boxy- or peanut-shaped bulge. During buckling, the phase space <i>J<i/><sub><i>z<i/><sub/> − <i>θ<i/><sub>res<sub/> undergoes a distortion creating an asymmetry in the position of the fixed points <i>θ<i/><sub>res<sub/> = 0 and <i>π<i/> and in banana-shaped orbits near these points. The fixed point <i>θ<i/><sub>res<sub/> = 0 may disappear completely. This also breaks the symmetry between the orbits, which are captured into resonance or go into circulation with decreasing <i>θ<i/><sub>res<sub/> near <i>θ<i/><sub>res<sub/> = 0 and <i>π<i/>. At the same time, near <i>θ<i/><sub>res<sub/> = 0, banana-shaped orbits with low vertical action <i>J<i/><sub><i>z<i/><sub/> appear. This reopens the path of orbital transformation through the fixed point, <i>θ<i/><sub>res<sub/> = 0. The phase space transformation and orbit transformation occur in a coordinated manner and lead to the smoothing of phase space perturbations and restoration of symmetry between orbits.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"15 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-resolution, high-efficiency narrowband spectroscopy with an s-p-phased holographic grating in double pass","authors":"C. Farret Jentink, F. Pepe, C. Lovis, C. Schwab, F. Wildi, A. Clawson","doi":"10.1051/0004-6361/202554218","DOIUrl":"https://doi.org/10.1051/0004-6361/202554218","url":null,"abstract":"<i>Context<i/>. High-resolution spectroscopy (R>50 000) in astronomy is typically performed with echelle-type spectrographs. The science for which these instruments have proven very effective is the detection of exoplanets through the radial velocity method, and the characterization of their atmospheres. For atmospheric characterization, it has been proven tedious to detect these signals, however mostly due to sensitivity constraints. While echelle-type spectrographs provide the necessary broad bandwidth for radial velocity measurements, they compromise total throughput. Additionally, the need for spectral order sorting complicates the optical design and reduces throughput further. A high spectral resolution and a limited bandpass are required to measure the exoplanet atmospheric absorption from the ground. Therefore, we propose a new method to for achieving a very high spectral resolution with significantly higher throughput within a limited bandpass that is focused on a specific spectral line or set of spectral lines of interest.<i>Aims<i/>. We describe and test a novel method for reaching a high spectral resolution with very high unpolarized diffraction efficiency in first-order employing a tuned high fringe-density volume-phase holographic (VPH) grating in double pass. We also provide laboratory tests that highlight the potential of this setup.<i>Methods<i/>. We used a wavelength-tunable laser to measure the dispersion and diffraction efficiency of a tuned VPH grating. We compared a single- and double-pass setup to verify the expected results. We also imaged the resulting spectrum to assess the optical quality.<i>Results<i/>. The VPH grating we tested can reach a diffraction-limited resolving power of >140 000 in double pass, with a peak double-pass diffraction efficiency of 79% for unpolarized light. We tested the grating at a more modest resolution of 38 000 given the sampling constraints. Based on current manufacturing abilities, we estimate that double-pass diffraction efficiencies over 50% with diffraction-limited resolving powers >200 000 should be within reach from the visible to the near-infrared, where the bandwidth is limited by the detector size.<i>Conclusions<i/>. For specific science cases where a relatively narrow wavelength regime at (ultra-)high spectral resolution is required, a double-pass VPH setup can prove to be very efficient. As the grating operates in first order, there is no need for a cross-dispersion, which allows very high total system throughputs and less complicated optics overall. This might enable ground-breaking science with smaller-class telescopes, with relatively compact instruments, and it might be of special interest for exoplanet atmospheric characterization because these observations typically require a large amount of observing time, a high signal-to-noise ratio, and a high spectral resolution.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"240 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Circumbinary disc interactions and stochastic dust obscuration in the post-asymptotic-giant-branch binary HD 213985","authors":"Krystian Iłkiewicz, Léa Planquart, Tomek Kamiński, Hans Van Winckel","doi":"10.1051/0004-6361/202453585","DOIUrl":"https://doi.org/10.1051/0004-6361/202453585","url":null,"abstract":"HD 213985 is an eccentric binary system with a post-AGB primary and a jet-launching secondary star. We confirm that the system photometric variability is likely due to obscuration by the inner edge of a circumbinary disc, similar to RVb-type RV Tau stars. The system has shown an increase in the orbital variability amplitude in optical photometric bands, along with irregular changes in its shape that often started to appear skewed. Variability in the Na D lines suggests that this behaviour may be driven by interactions between the circumbinary disc and outflows through the L2 Lagrange point. Moreover, HD 213985 has exhibited episodes of short-term fluctuations whose appearance is not strictly related to the orbital phase. This variability is consistent with obscuration by transient dust structure leading to weather-like variability patterns.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":"89 1","pages":""},"PeriodicalIF":6.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}