Monthly Notices of the Royal Astronomical Society最新文献

Origins and lifetimes of secular and tidal bars in simulated disc galaxies. 模拟盘状星系中世俗和潮汐洲的起源和寿命。

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2026-03-05 eCollection Date: 2026-04-01 DOI: 10.1093/mnras/stag428

Matthew Frosst, Danail Obreschkow, Aaron Ludlow, A Fraser-McKelvie

{"title":"Origins and lifetimes of secular and tidal bars in simulated disc galaxies.","authors":"Matthew Frosst, Danail Obreschkow, Aaron Ludlow, A Fraser-McKelvie","doi":"10.1093/mnras/stag428","DOIUrl":"10.1093/mnras/stag428","url":null,"abstract":"We analyse 307 Milky Way-mass disc galaxies in the TNG50 cosmological simulation to study the formation and evolution of stellar bars through secular processes and tidal interactions. About 90 per cent of these galaxies form at least one bar during their cosmic evolution. Most bars form rapidly in dynamically cold discs shortly after the central stellar mass exceeds that of dark matter (inside the stellar half-mass radius). In these cases, bar formation is consistent with secular instabilities driven by the disc's self-gravity, which organizes stellar orbits into a coherent bar structure. However, about 24 per cent of barred galaxies are dark matter-dominated at the time of bar formation. We trace the origin of these bars to tidal perturbations from passing or accreting satellites and streams, and introduce a new metric, [Formula: see text], to quantify the total external tidal field acting on each galaxy. We find that [Formula: see text] correlates negatively with the central stellar-to-dark matter mass ratio at the time of bar formation: the more dark-matter-dominated a disc, the stronger the tidal perturbation required to trigger a bar. Bars that form in dark matter-dominated discs under tidal perturbations are typically transient - disappearing in a few Gyr - unlike their counterparts which form in stellar-dominated discs. After a few orbital times, the properties of all bars are broadly similar, though their host galaxies differ: secular bars arise in thin, compact discs, whereas tidally induced bars can form in thicker, more extended discs whose properties closely resemble those of unbarred galaxies.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"547 4","pages":"stag428"},"PeriodicalIF":4.8,"publicationDate":"2026-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13011253/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147513578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Formation time-scales for stellar bars in diverse galactic discs. 不同星系盘中恒星棒的形成时间尺度。

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2026-02-23 eCollection Date: 2026-04-01 DOI: 10.1093/mnras/stag363

Matthew Frosst, Danail Obreschkow, Aaron Ludlow

{"title":"Formation time-scales for stellar bars in diverse galactic discs.","authors":"Matthew Frosst, Danail Obreschkow, Aaron Ludlow","doi":"10.1093/mnras/stag363","DOIUrl":"10.1093/mnras/stag363","url":null,"abstract":"We study the formation of stellar bars using 145 simulations of disc galaxies embedded in live and static dark matter haloes. We use the exponential bar growth time-scale, [Formula: see text], to quantify how disc structure and kinematics regulate the onset and rate of secular bar formation. We extend previous work to thicker and more turbulent discs, motivated by those observed at high redshift ([Formula: see text]). By revisiting several commonly used disc stability criteria - the Efstathiou-Lake-Negroponte parameter ([Formula: see text]), the Ostriker-Peebles ratio ([Formula: see text]), and the disc stellar mass fraction within 2.2 disc scale radii ([Formula: see text]) - we find that [Formula: see text], when expressed in terms of the disc's orbital period, follows a tight power law with each criteria. In Milky Way-like discs embedded in live haloes, bars form within a Hubble time if [Formula: see text], [Formula: see text], and [Formula: see text]. We show discs with higher velocity dispersion experience delayed bar growth and introduce an empirical relation that correctly describes the bar formation time-scales of all our live halo models. Bars in static haloes grow at roughly half the rate of those in live haloes and require substantially greater disc instability to do so.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"547 2","pages":"stag363"},"PeriodicalIF":4.8,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13017967/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147574799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Discs no more: the morphology of low-mass simulated galaxies in FIREbox. 不再是圆盘：FIREbox中低质量模拟星系的形态。

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2025-10-24 eCollection Date: 2025-12-01 DOI: 10.1093/mnras/staf1847

José A Benavides, Laura V Sales, Andrew Wetzel, Jorge Moreno, Robert Feldmann, Francisco J Mercado, James S Bullock, Philip F Hopkins, Claude-André Faucher-Giguère, Jonathan Stern, Coral Wheeler, Dušan Kereš

{"title":"Discs no more: the morphology of low-mass simulated galaxies in FIREbox.","authors":"José A Benavides, Laura V Sales, Andrew Wetzel, Jorge Moreno, Robert Feldmann, Francisco J Mercado, James S Bullock, Philip F Hopkins, Claude-André Faucher-Giguère, Jonathan Stern, Coral Wheeler, Dušan Kereš","doi":"10.1093/mnras/staf1847","DOIUrl":"10.1093/mnras/staf1847","url":null,"abstract":"We study the morphology of hundreds of simulated central galaxies in the stellar mass range [Formula: see text] 107.5-1011 [Formula: see text] from the FIREbox cosmological volume. We demonstrate that FIREbox is able to predict a wide variety of morphologies, spanning from disc-dominated objects to spheroidal galaxies supported by stellar velocity dispersion. However, the simulations predict a strong relation between morphology (degree of rotational support) and stellar mass: galaxies comparable to the Milky Way are often disc-dominated while the presence of stellar discs mostly vanishes for dwarfs with [Formula: see text][Formula: see text]. This defines a 'morphology transition' regime for galaxies with [Formula: see text] in which discs become increasingly common, but below which discs are rare. We show that burstiness in the star formation history and the deepening of the gravitational potential strongly correlate in our simulations with this transition regime, with discs forming in objects with lower levels of burstiness in the last [Formula: see text] Gyr and haloes with mass [Formula: see text] and above. While observations support a transition towards thicker discs in the regime of dwarfs, our results are in partial disagreement with observations of at least some largely rotationally supported gas discs in dwarfs with [Formula: see text][Formula: see text]. This study highlights dwarf morphology as a fundamental benchmark for testing future galaxy formation models.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"544 4","pages":"4651-4664"},"PeriodicalIF":4.8,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12680306/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145701393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Battle of the CH motions: aliphatic versus aromatic contributions to astronomical PAH emission and exploration of the aliphatic, aromatic, and ethynyl CH stretches. CH运动之战：脂肪族与芳香族对天文多环芳烃发射的贡献，以及脂肪族、芳香族和乙基CH延伸的探索。

IF 4.7 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2024-11-15 eCollection Date: 2024-12-01 DOI: 10.1093/mnras/stae2588

Vincent J Esposito, Salma Bejaoui, Brant E Billinghurst, Christiaan Boersma, Ryan C Fortenberry, Farid Salama

{"title":"Battle of the CH motions: aliphatic versus aromatic contributions to astronomical PAH emission and exploration of the aliphatic, aromatic, and ethynyl CH stretches.","authors":"Vincent J Esposito, Salma Bejaoui, Brant E Billinghurst, Christiaan Boersma, Ryan C Fortenberry, Farid Salama","doi":"10.1093/mnras/stae2588","DOIUrl":"10.1093/mnras/stae2588","url":null,"abstract":"Strong anharmonic coupling between vibrational states in polycyclic aromatic hydrocarbons (PAH) produces highly mixed vibrational transitions that challenge the current understanding of the nature of the astronomical mid-infrared PAH emission bands. Traditionally, PAH emission bands have been characterized as either aromatic or aliphatic, and this assignment is used to determine the fraction of aliphatic carbon in astronomical sources. In reality, each of the transitions previously utilized for such an attribution is highly mixed with contributions from both aliphatic and aromatic CH motions as well as non-CH motions such as CC stretches. High-resolution gas-phase IR absorption measurements of the spectra of the aromatic molecules indene and 2-ethynyltoluene at the Canadian Light Source combined with high-level anharmonic quantum chemical computations reveal the complex nature of these transitions, implying that the use of these features as a marker for the aliphatic fraction in astronomical sources is not uniquely true or actually predictive. Further, the presence of aliphatic, aromatic, and ethynyl CH groups in 2-ethynyltoluene provides an internally consistent opportunity to simultaneously study the spectroscopy of all three astronomically important groups. Finally, this study makes an explicit connection between fundamental quantum mechanical principles and macroscopic astronomical chemical physics, an important link necessary to untangle the lifecycle of stellar and planetary systems.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"535 4","pages":"3239-3251"},"PeriodicalIF":4.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11630826/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142812957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Predictive prognostic factors in patients with proximal humeral fracture treated with reverse shoulder arthroplasty. 反向肩关节置换术治疗肱骨近端骨折患者的预后预测因素。

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2024-10-01 Epub Date: 2023-06-27 DOI: 10.1177/17585732231185099

Nur Canbolat, Serkan Bayram, Yaşar Samet Gökçeoğlu, Okan Tezgel, Mehmet Kapicioğlu, Ali Erşen, Kerem Bilsel, Mehmet İlke Büget

{"title":"Predictive prognostic factors in patients with proximal humeral fracture treated with reverse shoulder arthroplasty.","authors":"Nur Canbolat, Serkan Bayram, Yaşar Samet Gökçeoğlu, Okan Tezgel, Mehmet Kapicioğlu, Ali Erşen, Kerem Bilsel, Mehmet İlke Büget","doi":"10.1177/17585732231185099","DOIUrl":"10.1177/17585732231185099","url":null,"abstract":"Background: We aimed to evaluate the predictive determitants in patients with PHF who were treated with reverse shoulder arthroplasty (RSA) by evaluating the patient characteristics and comorbidities and extensive preoperative laboratory parameters.Methods: With examining the records of elderly patients (over 65 years old) with PHF, who were admitted to our emergency department between 2009 and 2020. For evaluation of the survival, we performed Kaplan-Meirer statistical anaylses. A Cox algorithms (uni and multivariate) were applied to recognize factors (including clinical and laboratory parameters) which are associated with survival.Results: Sixty-three females and 17 males were included with a mean of 73.5 ± 7.4 years of age. Nineteen (23.83%) patients had decreased after the surgery, with a mean survival of 47.5 ± 32.7 months. There were 61 (76.3%) surviving patients with a mean survival of 67.4 ± 35.4 months. Survival rates in the first 6 months (n: 2 patients), first year (n: 3 patients), and second year (n: 6 patients) after surgery were 97.5%, 96.3%, and 92.3%, respectively.Conclusion: The age and preoperative hemoglobin level were independently related with poor survival in patients with PHF.Level of evidence: Level III Retrospective Cohort, Prognosis Study.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"339 1","pages":"518-526"},"PeriodicalIF":4.8,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11514117/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79740666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the sausage magnetohydrodynamic waves in magnetic flux tubes: finite plasma beta and phase mixing 磁通管中的香肠磁流体动力波：有限等离子体贝塔和相混合

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2024-09-19 DOI: 10.1093/mnras/stae2173

Zanyar Ebrahimi

{"title":"On the sausage magnetohydrodynamic waves in magnetic flux tubes: finite plasma beta and phase mixing","authors":"Zanyar Ebrahimi","doi":"10.1093/mnras/stae2173","DOIUrl":"https://doi.org/10.1093/mnras/stae2173","url":null,"abstract":"Over the past twenty years, there has been increasing evidence of the existence of sausage waves in the solar atmosphere. These observations make them useful tools in the context of atmospheric seismology. Here, we study sausage magnetohydrodynamic waves in a magnetic flux tube of non-zero plasma beta with a circular cross-section and a radially inhomogeneous plasma density. Solving numerically the equations of motion for an initial value problem, the spatio-temporal evolution of the velocity perturbations is obtained for different sets of parameters. We show that the ratio of the amplitudes of the longitudinal and radial perturbations is determined by the amount of plasma beta. Additionally, the longitudinal component of the velocity perturbation experiences phase-mixing within a layer surrounding the boundary of the flux tube with a rate depending on the amount of plasma beta. The results revealed that in the presence of a non-zero plasma beta, the flux tube exhibits oscillations in both the radial and longitudinal directions, characterized by a combination of two frequencies: one belonging to the slow continuum and the other to the Alfvén continuum. Also, the period of radial oscillation is obtained for different sets of parameters. The dependence of the period of the radial oscillation on the wavenumber confirms the results obtained in previous studies.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"7 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

引用次数: 0

CXOU J005245.0-722844: Discovery of a be star / white dwarf binary system in the SMC via a very fast, super-eddington X-ray outburst event CXOU J005245.0-722844：通过快速、超边顿X射线爆发事件发现SMC中的比星/白矮星双星系统

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2024-09-19 DOI: 10.1093/mnras/stae2176

T M Gaudin, M J Coe, J A Kennea, I M Monageng, D A H Buckley, A Udalski, P A Evans

{"title":"CXOU J005245.0-722844: Discovery of a be star / white dwarf binary system in the SMC via a very fast, super-eddington X-ray outburst event","authors":"T M Gaudin, M J Coe, J A Kennea, I M Monageng, D A H Buckley, A Udalski, P A Evans","doi":"10.1093/mnras/stae2176","DOIUrl":"https://doi.org/10.1093/mnras/stae2176","url":null,"abstract":"CXOU J005245.0-722844 is an X-ray source in the Small Magellanic Cloud (SMC) that has long been known as a Be/X-ray binary (BeXRB) star, containing an OBe main sequence star and a compact object. In this paper, we report on a new very fast X-ray outburst from CXOU J005245.0-722844. X-ray observations taken by Swift constrain the duration of the outburst to less than 16 days and find that the source reached super-Eddington X-ray luminosities during the initial phases of the eruption. The XRT spectrum of CXOU J005245.0-722844 during this outburst reveals a super-soft X-ray source, best fit by an absorbed thermal blackbody model. Optical and Ultraviolet follow-up observations from the Optical Gravitational Lensing Experiment (OGLE), Asteroid Terrestrial-impact Last Alert System (ATLAS), and Swift identify a brief ∼0.5 magnitude optical burst coincident with the X-ray outburst that lasted for less than 7 days. Optical photometry additionally identifies the orbital period of the system to be 17.55 days and identifies a shortening of the period to 17.14 days in the years leading up to the outburst. Optical spectroscopy from the Southern African Large Telescope (SALT) confirms that the optical companion is an early-type OBe star. We conclude from our observations that the compact object in this system is a white dwarf (WD), making this the seventh candidate Be/WD X-ray binary. The X-ray outburst is found to be the result of a very-fast, ultra-luminous nova similar to the outburst of MAXI J0158-744.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"28 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

引用次数: 0

Effects of nucleon-nucleon short-range correlation and symmetry energy on the evolution of newly born magnetars 核子-核子短程相关性和对称能对新生磁星演化的影响

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2024-09-19 DOI: 10.1093/mnras/stae2170

C X Liu, T F Feng, J M Dong

{"title":"Effects of nucleon-nucleon short-range correlation and symmetry energy on the evolution of newly born magnetars","authors":"C X Liu, T F Feng, J M Dong","doi":"10.1093/mnras/stae2170","DOIUrl":"https://doi.org/10.1093/mnras/stae2170","url":null,"abstract":"Millisecond magnetars are widely suggested as the central engines powering hydrogen-poor superluminous supernovae (SLSNe). These magnetars primarily lose huge rotational energy through gravitational wave radiation (GWR) and magnetic dipole radiation (MDR), with MDR serving as an energy source for SLSNe. We study the evolution of the magnetar spin, magnetic inclination angle, and the resulting thermal radiative luminosity of the SLSNe, where the impacts of the nucleon-nucleon short-range correlation, the mass and initial spin of the magnetar, and the density-dependent symmetry energy of the dense nuclear matter on the evolution are discussed. The relativistic mean-field theory is employed to calculate the nuclear matter properties, and we particularly concentrate on the time- and space-dependent bulk viscosity which is crucial for the magnetic inclination angle evolution. It is found that the nucleon-nucleon short-range correlation weakens the damping of bulk viscosity of dense matter and therefore inhibits the growth of magnetic inclination angle, and it reduces the MDR (GWR) peak luminosity of a canonical magnetar by several times while it raises the peak thermal radiation luminosity of SLSNe by several times. For magnetars with nonrotating mass obviously lower than the $1.4 , rm M_odot$ with slow initial rotation, the magnetic inclination angle is more likely to evolve towards 0 degrees quickly, and these magnetars are not suitable as the central engine for SLSNe. Within the ‘family’ of FSUGarnet interaction, a stiffer symmetry energy gives a lower threshold of direct Urca process and hence gives a much larger bulk viscosity coefficient, and thus it promotes the growth of the magnetic inclination angle and the GWR for canonical stars but reduces the peak brightness of SLSNe significantly.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"1 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

引用次数: 0

Kinematic study of the orion complex: Analysing the young stellar clusters from big and small structures 猎户座复合体的运动学研究：从大小结构分析年轻恒星簇群

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2024-09-19 DOI: 10.1093/mnras/stae2157

Sergio Sánchez-Sanjuán, Jesús Hernández, Ángeles Pérez-Villegas, Carlos Román-Zúñiga, Luis Aguilar, Javier Ballesteros-Paredes, Andrea Bonilla-Barroso

{"title":"Kinematic study of the orion complex: Analysing the young stellar clusters from big and small structures","authors":"Sergio Sánchez-Sanjuán, Jesús Hernández, Ángeles Pérez-Villegas, Carlos Román-Zúñiga, Luis Aguilar, Javier Ballesteros-Paredes, Andrea Bonilla-Barroso","doi":"10.1093/mnras/stae2157","DOIUrl":"https://doi.org/10.1093/mnras/stae2157","url":null,"abstract":"In this work, we analysed young stellar clusters with spatial and kinematic coherence in the Orion star-forming complex. For this study, we selected a sample of pre-main sequence candidates using parallaxes, proper motions and positions on the colour-magnitude diagram. After applying a hierarchical clustering algorithm in the 5D parameter space provided by Gaia DR3, we divided the recovered clusters into two regimes: Big Structures and Small Structures, defined by the number of detected stars per cluster. In the first regime, we found 13 stellar groups distributed along the declination axis in the regions where there is a high density of stars. In the second regime, we recovered 34 clusters classified into two types: 14 as small groups completely independent from the larger structures, including four candidates of new clusters, and 12 classified as sub-structures embedded within five larger clusters. Additionally, radial velocity data from APOGEE-2 and GALAH DR3 was included to study the phase space in some regions of the Orion complex. From the Big Structure regime, we found evidence of a general expansion in the Orion OB1 association over a common centre, giving a clue about the dynamical effects the region is undergoing. Likewise, in the Small Structure regime, the projected kinematics shows the ballistic expansion in the λ Orionis association and the detection of likely events of clusters’ close encounters in the OB1 association.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"7 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

引用次数: 0

Short-lived gravitational instability in isolated irradiated discs 孤立辐照圆盘中的短暂引力不稳定性

IF 4.8 3区物理与天体物理

Monthly Notices of the Royal Astronomical Society Pub Date : 2024-09-19 DOI: 10.1093/mnras/stae2167

Sahl Rowther, Daniel J Price, Christophe Pinte, Rebecca Nealon, Farzana Meru, Richard Alexander

{"title":"Short-lived gravitational instability in isolated irradiated discs","authors":"Sahl Rowther, Daniel J Price, Christophe Pinte, Rebecca Nealon, Farzana Meru, Richard Alexander","doi":"10.1093/mnras/stae2167","DOIUrl":"https://doi.org/10.1093/mnras/stae2167","url":null,"abstract":"Irradiation from the central star controls the temperature structure in protoplanetary discs. Yet simulations of gravitational instability typically use models of stellar irradiation with varying complexity, or ignore it altogether, assuming heat generated by spiral shocks is balanced by cooling, leading to a self-regulated state. In this paper, we perform simulations of irradiated, gravitationally unstable protoplanetary discs using 3D hydrodynamics coupled with live Monte-Carlo radiative transfer. We find that the resulting temperature profile is approximately constant in time, since the thermal effects of the star dominate. Hence, the disc cannot regulate gravitational instabilities by adjusting the temperatures in the disc. In a 0.1M⊙ disc, the disc instead adjusts by angular momentum transport induced by the spiral arms, leading to steadily decreasing surface density, and hence quenching of the instability. Thus, strong spiral arms caused by self-gravity would not persist for longer than ten thousand years in the absence of fresh infall, although weak spiral structures remain present over longer timescales. Using synthetic images at 1.3mm, we find that spirals formed in irradiated discs are challenging to detect. In higher mass discs, we find that fragmentation is likely because the dominant stellar irradiation overwhelms the stabilising influence of PdV work and shock heating in the spiral arms.","PeriodicalId":18930,"journal":{"name":"Monthly Notices of the Royal Astronomical Society","volume":"44 1","pages":""},"PeriodicalIF":4.8,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}

引用次数: 0