The Astrophysical Journal Letters最新文献_第5页

Resolving Emission from Small Dust Grains in the Blue Compact Dwarf II Zw 40 with JWST 用JWST解析蓝致密矮星II zw40中小尘埃颗粒的辐射

The Astrophysical Journal Letters Pub Date : 2025-09-29 DOI: 10.3847/2041-8213/ae0467

Thomas S.-Y. Lai, 劭愉賴, Sara Duval, J. D. T. Smith, Lee Armus, Adolf N. Witt, Karin Sandstrom, Elizabeth Tarantino, Shunsuke Baba, Alberto Bolatto, Grant P. Donnelly, Brandon S. Hensley, Masatoshi Imanishi, Laura Lenkic, Sean Linden, Takao Nakagawa, Henrik W. W. Spoon, Aditya Togi and Cory M. Whitcomb

{"title":"Resolving Emission from Small Dust Grains in the Blue Compact Dwarf II Zw 40 with JWST","authors":"Thomas S.-Y. Lai, 劭愉賴, Sara Duval, J. D. T. Smith, Lee Armus, Adolf N. Witt, Karin Sandstrom, Elizabeth Tarantino, Shunsuke Baba, Alberto Bolatto, Grant P. Donnelly, Brandon S. Hensley, Masatoshi Imanishi, Laura Lenkic, Sean Linden, Takao Nakagawa, Henrik W. W. Spoon, Aditya Togi and Cory M. Whitcomb","doi":"10.3847/2041-8213/ae0467","DOIUrl":"https://doi.org/10.3847/2041-8213/ae0467","url":null,"abstract":"We present James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) and Mid-infrared Instrument integral field spectroscopy of the nearby blue compact dwarf II Zw 40, which has a low metallicity of 25% of solar. Leveraging the high spatial/spectral resolution and wavelength coverage of JWST/NIRSpec, we present robust detections of the 3.3 μm polycyclic aromatic hydrocarbon (PAH) emission on 20 pc scales. The strength of the Pfδ emission relative to the 3.3 PAH feature is significantly stronger than typical higher-metallicity star-forming galaxies. We find that 3.3 μm PAH emission is concentrated near the northern super star cluster and is cospatial with CO gas. A strong correlation exists between the 3.3/11.3 PAH ratio and radiation hardness probed by [Ne iii]/[Ne ii], providing evidence of photodestruction of PAH molecules in intense radiation environments. Our analysis shows that while the overall PAH fraction is lower in II Zw 40 than in higher-metallicity galaxies, the contribution of the 3.3 μm PAH feature to the total PAH emission is higher. We propose that the PAH size distribution is fundamentally shaped by two competing mechanisms in low-metallicity environments: photodestruction and inhibited growth. Additionally, the high radiation field intensity in II Zw 40 suggests that multiphoton heating of PAHs may be an important effect. As one of the first spatially resolved studies of aromatic emission in a low-metallicity environment, our spectroscopic results offer practical guidance for future observations of the 3.3 μm PAH feature in low-metallicity galaxies using JWST.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145188708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Orbital Eccentricity and Spin–Orbit Misalignment Are Evidence that Neutron Star–Black Hole Mergers Form through Triple Star Evolution 轨道偏心率和自旋轨道错位是中子星-黑洞合并形成的证据

The Astrophysical Journal Letters Pub Date : 2025-09-29 DOI: 10.3847/2041-8213/ae055b

Jakob Stegmann and Jakub Klencki

{"title":"Orbital Eccentricity and Spin–Orbit Misalignment Are Evidence that Neutron Star–Black Hole Mergers Form through Triple Star Evolution","authors":"Jakob Stegmann and Jakub Klencki","doi":"10.3847/2041-8213/ae055b","DOIUrl":"https://doi.org/10.3847/2041-8213/ae055b","url":null,"abstract":"There is growing evidence that a substantial fraction of the neutron star–black holes (NSBHs) detected through gravitational waves merge with nonzero eccentricity or large black hole spin–orbit misalignment. This is in tension with leading formation scenarios to date. Residual eccentricity rules out formation from isolated binary stars, while neutron star (NS) natal kicks and unequal masses of NSBHs inhibit efficient pairing in dense stellar environments. We report that all observed properties—NSBH merger rate, eccentricity, and spin–orbit misalignment—are explained by the high prevalence of massive stellar triples in the field. Modeling their evolution from the zero-age main sequence, we investigate NSBH mergers caused by gravitational perturbations from a tertiary companion. The NS formation decisively impacts the triple stability, preferentially leaving behind surviving NSBHs in compact triple architectures with mild hierarchies. The rich three-body dynamics of compact, unequal-mass triples enables mergers across a wide range of orbital parameters and provides a natural explanation for an abundance of residual eccentricity and spin–orbit misalignment. We infer a total NSBH merger rate of –23 Gpc−3 yr−1 (within uncertainties on NS kicks) with a few 10% exhibiting residual eccentricity e20 > 0.1 or large spin–orbit misalignment , consistent with current observations. The mergers closely track the cosmic star formation rate due to short delay times (∼10–100 Myr), include a substantial fraction of burst-like highly eccentric systems (e20 > 0.9), and almost universally retain eccentricities e20 > 10−3 detectable by next-generation detectors. If evidence for eccentric and misaligned events solidifies, our results suggest that triple dynamics is the dominant formation channel of gravitational-wave events from NSBH mergers.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145188709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Black Hole Is Born: 3D General-relativistic Magnetohydrodynamic Simulation of Black Hole Formation from Core Collapse 一个黑洞的诞生：黑洞形成的三维广义相对论磁流体力学模拟

The Astrophysical Journal Letters Pub Date : 2025-09-29 DOI: 10.3847/2041-8213/ae08a6

Goni Halevi, Swapnil Shankar, Philipp Mösta, Roland Haas and Erik Schnetter

{"title":"A Black Hole Is Born: 3D General-relativistic Magnetohydrodynamic Simulation of Black Hole Formation from Core Collapse","authors":"Goni Halevi, Swapnil Shankar, Philipp Mösta, Roland Haas and Erik Schnetter","doi":"10.3847/2041-8213/ae08a6","DOIUrl":"https://doi.org/10.3847/2041-8213/ae08a6","url":null,"abstract":"We present the first three-dimensional, fully general-relativistic magnetohydrodynamic (3D GRMHD) simulation of a black hole (BH) formed from the collapsed core of a massive star. The ability to self-consistently capture the birth of a compact remnant in 3D is crucial for modeling natal BH properties (including masses, spins, and kicks), which are of particular interest in the era of gravitational-wave astronomy. However, such simulations have remained elusive due to extreme computational challenges and demands. We employ the GPU-accelerated dynamical-spacetime GRMHD code GRaM-X to follow the collapse, core bounce, shock propagation, and eventual BH formation of a massive stellar progenitor in full 3D. We initialize our simulation by mapping a one-dimensional (1D) model of a star with a zero-age-main-sequence mass of 45M⊙ to 3D. We use the core rotation velocity expected from stellar evolution modeling and a relatively weak dipolar magnetic field. The collapsing core drives a shock that reaches a maximum radius of roughly 170 km before stalling and does not lead to a successful explosion. The protoneutron star accretes matter before collapsing to form a BH tBH ≈ 325 ms after core bounce. The time of BH formation and initial BH mass are remarkably similar to those obtained with GR1D, a 1D general-relativistic neutrino-hydrodynamics code, to which we compare our results. We track the horizon of the newborn BH after formation and calculate a steady kick velocity of and a mass of MBH ≈ 2.62M⊙, which is still rising at the end of the simulation.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"97 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145188713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

RIOJA. JWST and ALMA Unveil the Inhomogeneous and Complex Interstellar Medium Structure in a Star-forming Galaxy at z = 6.81 里奥哈葡萄酒。JWST和ALMA揭示了z = 6.81恒星形成星系中不均匀和复杂的星际介质结构

The Astrophysical Journal Letters Pub Date : 2025-09-28 DOI: 10.3847/2041-8213/ae0574

Mitsutaka Usui, Ken Mawatari, Javier Álvarez-Márquez, Takuya Hashimoto, Yuma Sugahara, Rui Marques-Chaves, Akio K. Inoue, Luis Colina, Santiago Arribas, Carmen Blanco-Prieto, Yurina Nakazato, Naoki Yoshida, Tom J. L. C. Bakx, Daniel Ceverino, Luca Costantin, Alejandro Crespo Gómez, Masato Hagimoto, Hiroshi Matsuo, Wataru Osone, Yi W. Ren, Yoshinobu Fudamoto, Takeshi Hashigaya, Miguel Pereira-Santaella and Yoichi Tamura

{"title":"RIOJA. JWST and ALMA Unveil the Inhomogeneous and Complex Interstellar Medium Structure in a Star-forming Galaxy at z = 6.81","authors":"Mitsutaka Usui, Ken Mawatari, Javier Álvarez-Márquez, Takuya Hashimoto, Yuma Sugahara, Rui Marques-Chaves, Akio K. Inoue, Luis Colina, Santiago Arribas, Carmen Blanco-Prieto, Yurina Nakazato, Naoki Yoshida, Tom J. L. C. Bakx, Daniel Ceverino, Luca Costantin, Alejandro Crespo Gómez, Masato Hagimoto, Hiroshi Matsuo, Wataru Osone, Yi W. Ren, Yoshinobu Fudamoto, Takeshi Hashigaya, Miguel Pereira-Santaella and Yoichi Tamura","doi":"10.3847/2041-8213/ae0574","DOIUrl":"https://doi.org/10.3847/2041-8213/ae0574","url":null,"abstract":"We report the discovery of a complex density-stratified interstellar medium (ISM) in the star-forming galaxy COS-2987 at z = 6.81, revealed by the unprecedented synergy between James Webb Space Telescope (JWST)/NIRSpec integral field spectroscopy and Atacama Large Millimeter/submillimeter Array (ALMA) observations. These observations detect key emission lines, including [O ii] λλ 3727, 3730, [O iii] 4364, [O iii] λλ 4960, 5008, and [O iii] 88 μm, as well as Hα and Hβ. JWST spectroscopy alone indicates ISM properties that are typical for galaxies at z ∼ 7. These include low dust extinction (AV ≈ 0.14 mag), moderate electron density (ne ≈ 500 cm−3), and low gas-phase metallicity (∼10%). However, the strong far-infrared [O iii] 88 μm emission detected by ALMA cannot be explained by a single-component ionized medium with uniform electron density and temperature. Instead, a two-component ISM model—comprising compact, high-temperature, and high-density gas components (Te ≈ 26,000 K; ne ≈ 600 cm−3) and an extended, cooler, and lower-density component (Te ≈ 8000 K; ne ≈ 50 cm−3)—successfully reproduces the observed line ratios of [O iii] 88 μm/[O iii] 5008 Å and [O iii] 4364/[O iii] 5008 Å, with a volume ratio of 1 : 300 between the two components. Our results demonstrate that JWST alone probes only a fraction of the ISM and highlight the critical importance of combining JWST and ALMA to reveal the density-stratified ISM of early galaxies.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Carbon-rich Disk Surrounding a Planetary-mass Companion 富含碳的圆盘围绕着行星质量的伴星

The Astrophysical Journal Letters Pub Date : 2025-09-28 DOI: 10.3847/2041-8213/ae0290

Gabriele Cugno and Sierra L. Grant

{"title":"A Carbon-rich Disk Surrounding a Planetary-mass Companion","authors":"Gabriele Cugno and Sierra L. Grant","doi":"10.3847/2041-8213/ae0290","DOIUrl":"https://doi.org/10.3847/2041-8213/ae0290","url":null,"abstract":"During the final assembly of gas giant planets, circumplanetary disks (CPDs) of gas and dust form due to the conservation of angular momentum, providing material to be accreted onto the planet and the ingredients for moons. The composition of these disks has remained elusive, as their faint nature and short separations from their host stars have limited our ability to access them. Now, with the spatial and spectral resolution of the JWST/MIRI Medium-Resolution Spectrograph, we can observe and characterize this reservoir for wide-orbit planetary-mass companions for the first time. We present the mid-infrared spectrum from the CPD surrounding the young companion CT Cha b. The data show a carbon-rich chemistry with seven carbon-bearing molecules (up to C6H6) and one isotopolog detected and indicate a high gaseous C/O > 1 that is in contrast with the elemental abundance ratios typically measured in directly imaged gas giant atmospheres. This carbon-rich chemistry is also in stark contrast to the spectrum of the disk surrounding the host star, CT Cha A, which shows no carbon-bearing molecules. This difference in disk chemistry between the host disk and its companion indicates rapid, divergent chemical evolution on ∼million-year timescales. Nonetheless, the chemical properties of the CPD follow trends observed in isolated objects, where disks transition from an oxygen-rich to carbon-rich composition with decreasing host mass. Our results provide the first direct insight into the chemical and physical properties of material being accreted onto a gas giant analog and into its potential moon system.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145182823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Survival of 2D Turbulence in the Local Interstellar Medium 局部星际介质中二维湍流的生存

The Astrophysical Journal Letters Pub Date : 2025-09-28 DOI: 10.3847/2041-8213/ae07c3

Masaru Nakanotani and Gary P. Zank

{"title":"Survival of 2D Turbulence in the Local Interstellar Medium","authors":"Masaru Nakanotani and Gary P. Zank","doi":"10.3847/2041-8213/ae07c3","DOIUrl":"https://doi.org/10.3847/2041-8213/ae07c3","url":null,"abstract":"The evolution of 2D turbulence in the partially ionized local interstellar medium is investigated using 2D MHD simulations coupled with a neutral hydrogen gas via charge exchange. While it has been discussed that Alfvén and compressible waves are damped in a partially ionized plasma due to plasma-neutral drag effects, little is known about how (quasi-)2D turbulence (or magnetic flux ropes) interacts with a neutral gas. We expect that quasi-2D turbulence is unaffected by such an interaction since there is no associated velocity fluctuation, and our nonlinear simulation reveals that magnetic fluctuations in a partially ionized plasma are undamped, whereas the magnetic, kinetic plasma, and neutral spectra are modified to a −7/3 spectrum. The modified spectra can be explained by a Kolmogorov-type scaling law in which the turbulence cascade occurs through magnetic reconnection, as observed in the simulation. Our result suggests that magnetic fluctuations perpendicular to the background magnetic field cascade down to smaller scales without damping, whereas Alfvénic turbulence is damped at the characteristic scale associated with the plasma-neutral drag, and LISM turbulence will be magnetically rather than kinetically dominated. We note that the possible dominance of quasi-2D turbulence in the local interstellar medium can be crucial to the diffusive transport of cosmic rays.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145188715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modeling Tails of Escaping Gas in Exoplanet Atmospheres with Harmonica 用Harmonica模拟系外行星大气中逸出气体的尾部

The Astrophysical Journal Letters Pub Date : 2025-09-28 DOI: 10.3847/2041-8213/adfb77

Carlos Gascón, Mercedes López-Morales, Shreyas Vissapragada, Morgan MacLeod, Hannah R. Wakeford, David Grant, Ignasi Ribas and Guillem Anglada-Escudé

{"title":"Modeling Tails of Escaping Gas in Exoplanet Atmospheres with Harmonica","authors":"Carlos Gascón, Mercedes López-Morales, Shreyas Vissapragada, Morgan MacLeod, Hannah R. Wakeford, David Grant, Ignasi Ribas and Guillem Anglada-Escudé","doi":"10.3847/2041-8213/adfb77","DOIUrl":"https://doi.org/10.3847/2041-8213/adfb77","url":null,"abstract":"Exoplanets that reside close to their host stars, and therefore receive substantial amounts of X-ray and ultraviolet radiation, are prone to suffer from strong atmospheric escape. This can lead to the creation of an envelope of escaping gas along the planet’s orbital trajectory, often referred to as a tail. When transiting in front of their host star, these tails can not only produce larger depths in the transit light curves but also introduce significant asymmetries between ingress and egress. Using the publicly available software Harmonica, we present a method to model the light curves of transiting planets surrounded by extended envelopes of escaping gas and subsequently infer the shape and size of the latter. We apply this method to the JWST NIRISS/SOSS observations of HAT-P-18 b, which show pronounced helium tail features in the spectroscopic light curve of the metastable helium triplet at 10830 Å. Our model reveals that, in order to fit the observed light curve of HAT-P-18 b, the planet must possess a trailing helium tail of planetary radii. We carry out injection-recovery tests to validate the effectiveness of the proposed methodology. We demonstrate that, with sufficient precision, we would be able to fit a multilayer envelope to the data, which would provide insight into the relative radial variations in the opacity profile.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"114 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145188717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

JWST Detection of a Carbon-dioxide-dominated Gas Coma Surrounding Interstellar Object 3I/ATLAS JWST探测到环绕星际物体3I/ATLAS的以二氧化碳为主的气体彗发

The Astrophysical Journal Letters Pub Date : 2025-09-25 DOI: 10.3847/2041-8213/ae0647

Martin A. Cordiner, Nathan X. Roth, Michael S. P. Kelley, Dennis Bodewits, Steven B. Charnley, Maria N. Drozdovskaya, Davide Farnocchia, Marco Micheli, Stefanie N. Milam, Cyrielle Opitom, Megan E. Schwamb, Cristina A. Thomas and Stefano Bagnulo

{"title":"JWST Detection of a Carbon-dioxide-dominated Gas Coma Surrounding Interstellar Object 3I/ATLAS","authors":"Martin A. Cordiner, Nathan X. Roth, Michael S. P. Kelley, Dennis Bodewits, Steven B. Charnley, Maria N. Drozdovskaya, Davide Farnocchia, Marco Micheli, Stefanie N. Milam, Cyrielle Opitom, Megan E. Schwamb, Cristina A. Thomas and Stefano Bagnulo","doi":"10.3847/2041-8213/ae0647","DOIUrl":"https://doi.org/10.3847/2041-8213/ae0647","url":null,"abstract":"3I/ATLAS is the third confirmed interstellar object to visit our solar system and only the second to display a clear coma. Infrared spectroscopy with the James Webb Space Telescope (JWST) provides the opportunity to measure its coma composition and determine the primary activity drivers. We report the first results from our JWST NIRSpec campaign for 3I/ATLAS, at an inbound heliocentric distance of rH = 3.32 au. The spectral images (spanning 0.6–5.3 μm) reveal a CO2-dominated coma, with enhanced outgassing in the sunward direction and the presence of H2O, CO, water ice, dust, and a tentative detection of OCS. The coma CO2/H2O mixing ratio of 7.6 ± 0.3 is among the highest ever observed in a comet, and is 4.5σ above the trend as a function of rH for long-period and Jupiter-family comets (excluding the outlier C/2016 R2). Our observations are compatible with an intrinsically CO2-rich nucleus, which may indicate that 3I/ATLAS contains ices exposed to higher levels of radiation than solar system comets or that it formed close to the CO2 ice line in its parent protoplanetary disk. A relatively low coma H2O gas abundance may also be implied, for example, due to inhibited heat penetration into the nucleus, which could suppress the H2O sublimation rate relative to CO2 and CO.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"94 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Coexistence of Longitudinal and Transverse Oscillations in Polar Plumes Observed with Solar Orbiter/Extreme Ultraviolet Imager 用太阳轨道器/极紫外成像仪观测到的极地羽流纵向和横向振荡共存

The Astrophysical Journal Letters Pub Date : 2025-09-25 DOI: 10.3847/2041-8213/ae071e

Upasna Baweja, Vaibhav Pant, S. Krishna Prasad, Arpit Kumar Shrivastav, Tom Van Doorsselaere, Nancy Narang, Cis Verbeeck, M. Saleem Khan and David Berghmans

{"title":"Coexistence of Longitudinal and Transverse Oscillations in Polar Plumes Observed with Solar Orbiter/Extreme Ultraviolet Imager","authors":"Upasna Baweja, Vaibhav Pant, S. Krishna Prasad, Arpit Kumar Shrivastav, Tom Van Doorsselaere, Nancy Narang, Cis Verbeeck, M. Saleem Khan and David Berghmans","doi":"10.3847/2041-8213/ae071e","DOIUrl":"https://doi.org/10.3847/2041-8213/ae071e","url":null,"abstract":"Magnetohydrodynamic waves play a key role in heating the solar corona and driving the solar wind. Recent observations have shown the presence of slow magnetoacoustic and Alfvénic waves in polar plumes and interplumes. However, a complete understanding of wave dynamics in the polar regions has long been limited by the lack of simultaneous high-resolution observations. In this study, we utilize a high-spatial-resolution (210 km per pixel) and high-cadence (5 s) data set from the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter, acquired on 2021 September 14. Our findings reveal the simultaneous presence of slow magnetoacoustic and Alfvénic waves within the same polar plumes. For the slow magnetoacoustic waves, the amplitudes of the propagating disturbances are 1.4%–3.2% of the background intensity, with periodicities of 9 minutes, and the projected speeds of these disturbances range between 115 and 125 km s−1. The corresponding electron temperatures in plumes range between 0.58 and 0.69 MK. The damping lengths of these propagating disturbances for five plumes are ≈2.4–7.1 Mm. The propagating disturbances are also detected in the fine-scale substructures within the plumes. Alfvénic waves, on the other hand, are detected with average displacement amplitude, periodicity, and velocity amplitude of 165 ± 82 km, 93 ± 39 s, and 12 ± 7 km s−1, respectively. The ranges for the displacement amplitude, period, and velocity amplitude are 50–600 km, 50–250 s, and 3–32 km s−1, respectively. These results mark the first demonstration of the ability of Solar Orbiter/EUI to simultaneously detect both slow magnetoacoustic and Alfvénic wave modes extending up to 20 Mm in polar plumes.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Astrometric Methods for Detecting Exomoons Orbiting Imaged Exoplanets: Prospects for Detecting Moons Orbiting a Giant Planet in α Centauri A’s Habitable Zone 探测环绕系外行星的系外卫星的天体测量方法：探测在半人马座α a宜居带环绕一颗巨大行星的卫星的前景

The Astrophysical Journal Letters Pub Date : 2025-09-25 DOI: 10.3847/2041-8213/ae0741

Kevin Wagner, Ewan Douglas, Steve Ertel, Kyran Grattan, S. Pete Worden, Aniket Sanghi, Billy Quarles and Charles Beichman

{"title":"Astrometric Methods for Detecting Exomoons Orbiting Imaged Exoplanets: Prospects for Detecting Moons Orbiting a Giant Planet in α Centauri A’s Habitable Zone","authors":"Kevin Wagner, Ewan Douglas, Steve Ertel, Kyran Grattan, S. Pete Worden, Aniket Sanghi, Billy Quarles and Charles Beichman","doi":"10.3847/2041-8213/ae0741","DOIUrl":"https://doi.org/10.3847/2041-8213/ae0741","url":null,"abstract":"Nearby giant exoplanets offer an opportunity to search for moons (exomoons) orbiting them. Here, we present a simulation framework for investigating the possibilities of detecting exomoons via their astrometric signal in planet-to-star relative astrometry. We focus our simulations on α Centauri A, orbited by a hypothetical giant planet consistent with candidate detections in Very Large Telescope and James Webb Space Telescope observations. We consider a variety of observatory architectures capable of searching for exomoons, including upcoming facilities and also a hypothetical dedicated facility—e.g., a purpose-built space telescope with diameter = 3 m, central observing wavelength of 500 nm, and contrast-limited performance of ∼10−9 in 1 hr observations. We find that such a facility would be capable of detecting ∼Earth-mass moons in a 5 yr campaign, assuming a Saturn-mass planet. More generally, we simulate expected detection limits for a variety of levels of astrometric precision. We find that moons as small as ∼0.2 M⊕ on orbital periods of 4−30 days can be detected with astrometric precision of 0.1 mas and observing cadence of 1 hr over a 5 yr campaign. Additionally, we find that a 39 m ground-based telescope can detect Earth-sized exomoons orbiting the same hypothetical planet with a more modest observing cadence of 1 day. We discuss these results as motivation for a dedicated space observatory as well as a more detailed study of the physical parameters of a greater variety of star–planet–moon systems.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145153943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0