The Astrophysical Journal Letters最新文献_第2页

Correlation between Supergranular Lane Widths and Sunspot Number; A Simple Way to Predict the Amplitude of Sunspot Cycle 超粒道宽度与太阳黑子数量之间的相关性；预测太阳黑子周期振幅的简单方法

The Astrophysical Journal Letters Pub Date : 2023-12-01 DOI: 10.3847/2041-8213/ad13e9

K. P. Raju, Jagdev Singh, B. Ravindra, Muthu Priyal

引用次数: 0

Investigations of Flaring Plasma Parameters during an M-class Flare Using the Differential Evolution Method and XSM/Chandrayaan-2 Observations 利用差分演化法和 XSM/Chandrayaan-2 观测数据研究 M 级耀斑期间的等离子体参数

The Astrophysical Journal Letters Pub Date : 2023-12-01 DOI: 10.3847/2041-8213/ad0f23

A. Kępa, M. Siarkowski, A. Awasthi, J. Sylwester, B. Sylwester

{"title":"Investigations of Flaring Plasma Parameters during an M-class Flare Using the Differential Evolution Method and XSM/Chandrayaan-2 Observations","authors":"A. Kępa, M. Siarkowski, A. Awasthi, J. Sylwester, B. Sylwester","doi":"10.3847/2041-8213/ad0f23","DOIUrl":"https://doi.org/10.3847/2041-8213/ad0f23","url":null,"abstract":"We employ the differential evolution (DE) method to analyze observations from the Solar X-Ray Monitor on board the Chandrayaan-2 spacecraft. DE belongs to the family of evolutionary algorithms that find solutions using mechanisms inspired by biological processes. This approach enables us to simultaneously calculate the distribution of the differential emission measure and elemental abundances through an iterative process. We establish a model for the emission sources of flaring plasma, incorporating temperature, emission measure, and abundances of eight elements: Mg, Al, Si, S, Ar, Ca, Fe, and Ni, for an M3.9 GOES-class solar flare that occurred on 2021 May 7 (SOL2021-05-07T19:04). Our analysis covers various phases of the flare, determining the evolution of temperature, emission measure, and elemental abundances. Additionally, utilizing data from the Spectrometer Telescope for Imaging X-rays on board the Solar Orbiter, we investigate the evolution of hard X-ray source morphology, source volume, electron density, and thermal behavior of the flaring plasma throughout the event. The results reveal notable variations in elemental abundances between photospheric and coronal values during different flare phases. This emphasizes the significance of elemental abundance information in comprehending X-ray emissions during solar flares.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139026487","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

Time-dependent Dynamics of the Corona 日冕随时间变化的动力学特性

The Astrophysical Journal Letters Pub Date : 2023-12-01 DOI: 10.3847/2041-8213/ad00bd

E. Mason, R. Lionello, Cooper Downs, Jon A. Linker, R. Caplan, M. DeRosa

{"title":"Time-dependent Dynamics of the Corona","authors":"E. Mason, R. Lionello, Cooper Downs, Jon A. Linker, R. Caplan, M. DeRosa","doi":"10.3847/2041-8213/ad00bd","DOIUrl":"https://doi.org/10.3847/2041-8213/ad00bd","url":null,"abstract":"We present in this Letter the first global comparison between traditional line-tied steady-state magnetohydrodynamic models and a new, fully time-dependent thermodynamic magnetohydrodynamic simulation of the global corona. To approximate surface magnetic field distributions and magnitudes around solar minimum, we use the Lockheed Evolving Surface-Flux Assimilation Model to obtain input maps that incorporate flux emergence and surface flows over a full solar rotation, including differential rotation and meridional flows. Each time step evolves the previous state of the plasma with a new magnetic field input boundary condition, mimicking photospheric driving on the Sun. We find that this method produces a qualitatively different corona compared to steady-state models. The magnetic energy levels are higher in the time-dependent model, and coronal holes evolve more along the following edge than they do in steady-state models. Coronal changes, as illustrated with forward-modeled emission maps, evolve on longer timescales with time-dependent driving. We discuss implications for active and quiet Sun scenarios, solar wind formation, and widely used steady-state assumptions like potential field source surface calculations.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138607852","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

Gas-phase Ortho-to-para Ratio of Formaldehyde Formed at Low Temperatures in Laboratory Ices 实验室冰层中低温形成的甲醛气相正对比例

The Astrophysical Journal Letters Pub Date : 2023-12-01 DOI: 10.3847/2041-8213/ad0bee

K. M. Yocum, O. Wilkins, J. C. Bardwell, S. N. Milam, P. Gerakines

引用次数: 0

Erratum: “The Changing Lightcurve of the Double-mode RR Lyrae Variable Star V338 Boo” (2021, ApJL, 916, L12) 勘误:“双模RR天琴座变星V338 Boo的光变曲线变化”(2021,ApJL, 916, L12)

The Astrophysical Journal Letters Pub Date : 2023-09-01 DOI: 10.3847/2041-8213/acf133

Kenneth Carrell, Ronald Wilhelm, F. Olsen, Andrew Tom, Garath Vetters, Anna McElhannon

引用次数: 0

Iron Isotope Constraints on the Structure of the Early Solar System 铁同位素对早期太阳系结构的约束

The Astrophysical Journal Letters Pub Date : 2023-09-01 DOI: 10.3847/2041-8213/acefd1

Y. Marrocchi, M. Piralla, F. Tissot

{"title":"Iron Isotope Constraints on the Structure of the Early Solar System","authors":"Y. Marrocchi, M. Piralla, F. Tissot","doi":"10.3847/2041-8213/acefd1","DOIUrl":"https://doi.org/10.3847/2041-8213/acefd1","url":null,"abstract":"The recent advent of nontraditional isotopic systems has revealed that meteorites display a fundamental isotopic dichotomy between noncarbonaceous (NC) and carbonaceous (C) groups, which represent material from the inner and outer solar system, respectively. On the basis of iron isotope anomalies, this view has recently been challenged in favor of a circumsolar disk structured into three distinct reservoirs (the so-called isotopic trichotomy). In this scenario, the CI chondrites—a rare type of carbonaceous chondrites with chemical composition similar to that of the Sun’s photosphere—would sample a distinct source region than other carbonaceous chondrites, located beyond Saturn’s orbit. Here, we report a model based on the available data for both mass-dependent fractionation of Te stable isotopes and mass-independent Fe nucleosynthetic anomalies. On the basis of the Te–Fe isotopic correlation defined by all carbonaceous chondrites including CIs, we show that the NC-CC dichotomy extends to Fe isotopes. Our finding thus supports (i) the existence of only two reservoirs in the early solar system and (ii) the ubiquitous presence of CI-like dust throughout the carbonaceous reservoir. Our approach also reveals that the carrier phase of 54Fe anomalies corresponds to Fe–Ni metal beads mostly located within chondrules. Finally, we propose that the CC chondrule component records a constant mix of refractory inclusions and NC-like dust.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129520382","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

Dispersive Suprathermal Ion Events Observed by the Parker Solar Probe Mission 帕克太阳探测器任务观测到的色散超热离子事件

The Astrophysical Journal Letters Pub Date : 2023-09-01 DOI: 10.3847/2041-8213/acf21c

S. Alnussirat, R. Livi, D. E. Larson, A. Rahmati, P. Whittlesey, O. Romeo, S. Badman, Milo Buitrago-Casas, Juan Carlos, Martínez Oliveros, M. Pulupa, S. Bale, J. Huang, J. Verniero, N. R. ﬁ, D. Mitchell, D. J. McComas, Matt Hill, Christina Cohen

引用次数: 0

The Discrepancy between Observed and Predicted Heliospheric Energetic Neutral Atoms below Solar Wind Energy 太阳风能量以下的日球层高能中性原子的观测与预测差异

The Astrophysical Journal Letters Pub Date : 2023-09-01 DOI: 10.3847/2041-8213/aced9b

A. Galli, I. Baliukin, M. Kornbleuth, M. Opher, S. Fuselier, Justyna M. Sokół, K. Dialynas, M. Dayeh, V. Izmodenov, J. Richardson

引用次数: 0

Observations of Twist, Current Helicity, and Writhe in the Magnetic Knots of δ-sunspots Consistent with the Kink Instability of a Highly Twisted Flux Rope δ-太阳黑子磁结中的扭、电流螺旋度和扭的观测与高扭通量绳的扭不稳定性一致

The Astrophysical Journal Letters Pub Date : 2023-08-31 DOI: 10.3847/2041-8213/acf0c6

P. Levens, A. Norton, M. Linton, K. Knizhnik, Y. Liu

{"title":"Observations of Twist, Current Helicity, and Writhe in the Magnetic Knots of δ-sunspots Consistent with the Kink Instability of a Highly Twisted Flux Rope","authors":"P. Levens, A. Norton, M. Linton, K. Knizhnik, Y. Liu","doi":"10.3847/2041-8213/acf0c6","DOIUrl":"https://doi.org/10.3847/2041-8213/acf0c6","url":null,"abstract":"We measure current helicity (H r c ) as well as proxies for twist (α r ) and writhe (W) in the isolated magnetic knots of three delta (δ)-sunspots and report that the observations are consistent with a kink instability acting on a highly twisted flux tube. δ-spots are active regions (ARs) in which positive and negative umbrae share a penumbra. We identify and isolate “magnetic knots,” i.e., opposite polarity umbrae that are in close proximity and forming the δ-configuration, in ARs NOAA 11158, 11267, and 11476 as observed with data from the Solar Dynamic Observatory Helioseismic and Magnetic Imager. We find that H r c , α r , and W have the same sign for each magnetic knot, as predicted in simulations of a kink instability acting on highly twisted flux tubes. The deformed flux tube causing the δ-formation, the magnetic knot, is only a portion of the entire AR and demonstrates the potential for the kink instability to act on a smaller spatial scale within the AR. Each magnetic footpoint contains a single sign of the radial current, J r , which suggests that we are observing the core of the flux rope without return currents. As a counterexample, we analyze one β-spot that shows H r c and α r have the opposite signs of W. While our observations support the formation mechanism of the magnetic knots in δ-spots being the kink instability, a much larger sample is needed to determine confidently the prevalence of the kink instability as the cause of flux tube deformation.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129437245","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

Discovery of Super-enriched Gas ∼1 Gyr after the Big Bang 大爆炸后超富集气体~ 1 Gyr的发现

The Astrophysical Journal Letters Pub Date : 2023-08-31 DOI: 10.3847/2041-8213/aceefe

Jianghao 江豪 Huyan 呼延, V. Kulkarni, Suraj Poudel, N. Tejos, C. Péroux, S. López

{"title":"Discovery of Super-enriched Gas ∼1 Gyr after the Big Bang","authors":"Jianghao 江豪 Huyan 呼延, V. Kulkarni, Suraj Poudel, N. Tejos, C. Péroux, S. López","doi":"10.3847/2041-8213/aceefe","DOIUrl":"https://doi.org/10.3847/2041-8213/aceefe","url":null,"abstract":"Abundances of chemical elements in the interstellar and circumgalactic media of high-redshift galaxies offer important constraints on the nucleosynthesis by early generations of stars. Damped Lyα absorbers (DLAs) in spectra of high-redshift background quasars are excellent sites for obtaining robust measurements of element abundances in distant galaxies. Past studies of DLAs at redshifts z > 4 have measured abundances of ≲0.01 solar. Here we report the discovery of a DLA at z = 4.7372 with an exceptionally high degree of chemical enrichment. We estimate the H i column density in this absorber to be log (N H I/cm−2) = 20.48 ± 0.15. Our analysis shows unusually high abundances of carbon and oxygen ([C/H] = 0.88 ± 0.17, [O/H] = 0.71 ± 0.16). Such a high level of enrichment a mere 1.2 Gyr after the Big Bang is surprising because of insufficient time for the required amount of star formation. To our knowledge, this is the first supersolar absorber found at z > 4.5. We find the abundances of Si and Mg to be [Si/H] = −0.56−0.35+0.40 and [Mg/H] = 0.59−0.50+0.27 , confirming the metal-rich nature of this absorber. By contrast, Fe shows a much lower abundance ([Fe/H] = −1.53−0.15+0.15 ). We discuss implications of our results for galactic chemical evolution models. The metallicity of this absorber is higher than that of any other known DLA and is >2 orders of magnitude above predictions of chemical evolution models and the N H I-weighted mean metallicity from previous studies at z > 4.5. The relative abundances (e.g., [O/Fe] = 2.29 ± 0.05, [C/Fe] = 2.46 ± 0.08) are also highly unusual compared to predictions for enrichment by early stars.","PeriodicalId":179976,"journal":{"name":"The Astrophysical Journal Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131182358","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