首页 > 最新文献

arXiv - PHYS - Solar and Stellar Astrophysics最新文献

英文 中文
JWST imaging of the closest globular clusters -- IV. Chemistry, luminosity, and mass functions of the lowest-mass members in the NIRISS parallel fields JWST 对最接近球状星团的成像 -- IV.NIRISS平行场中最低质量成员的化学、光度和质量函数
Pub Date : 2024-09-10 DOI: arxiv-2409.06774
M. Libralato, R. Gerasimov, L. Bedin, J. Anderson, D. Apai, A. Bellini, A. J. Burgasser, M. Griggio, D. Nardiello, M. Salaris, M. Scalco, E. Vesperini
We present observations of the two closest globular clusters, NGC 6121 andNGC 6397, taken with the NIRISS detector of JWST. The combination of our newJWST data with archival Hubble Space Telescope (HST) images allows us tocompute proper motions, disentangle cluster members from field objects, andprobe the main sequence (MS) of the clusters down to <0.1 $M_odot$ as well asthe brighter part of the white-dwarf sequence. We show that theoreticalisochrones fall short in modeling the low-mass MS and discuss possibleexplanations for the observed discrepancies. Our analysis suggests that thelowest-mass members of both clusters are significantly more metal-rich andoxygen-poor than their higher-mass counterparts. It is unclear whether thedifference is caused by a genuine mass-dependent chemical heterogeneity,low-temperature atmospheric processes altering the observed abundances, orsystematic shortcomings in the models. We computed the present-day localluminosity and mass functions of the two clusters; our data reveal a strongflattening of the mass function indicative of a significant preferential lossof low-mass stars in agreement with previous dynamical models for these twoclusters. We have made our NIRISS astro-photometric catalogs and stacked imagespublicly available to the community.
我们将介绍利用 JWST 的近红外ISS 探测器对两个距离最近的球状星团 NGC 6121 和 NGC 6397 的观测结果。将JWST的新数据与哈勃太空望远镜(HST)的存档图像结合起来,我们就可以计算适当的运动,将星团成员从场天体中分离出来,并探测星团的主序列(MS),最小可达<0.1 $M_odot$,以及白矮星序列中较亮的部分。我们发现理论上的等距线并不能模拟低质量的主序,并讨论了观测到的差异的可能解释。我们的分析表明,这两个星团中质量最低的成员比质量较高的成员富含金属和贫氧。目前还不清楚造成这种差异的原因是与质量相关的真正的化学异质性,还是低温大气过程改变了观测到的丰度,或者是模型的系统性缺陷。我们计算了这两个星团现在的光度和质量函数;我们的数据显示质量函数的强烈扁平化,表明低质量恒星的大量优先损耗,这与这两个星团以前的动力学模型是一致的。我们已经向社会公开了我们的 NIRISS 天文光度目录和叠加图像。
{"title":"JWST imaging of the closest globular clusters -- IV. Chemistry, luminosity, and mass functions of the lowest-mass members in the NIRISS parallel fields","authors":"M. Libralato, R. Gerasimov, L. Bedin, J. Anderson, D. Apai, A. Bellini, A. J. Burgasser, M. Griggio, D. Nardiello, M. Salaris, M. Scalco, E. Vesperini","doi":"arxiv-2409.06774","DOIUrl":"https://doi.org/arxiv-2409.06774","url":null,"abstract":"We present observations of the two closest globular clusters, NGC 6121 and\u0000NGC 6397, taken with the NIRISS detector of JWST. The combination of our new\u0000JWST data with archival Hubble Space Telescope (HST) images allows us to\u0000compute proper motions, disentangle cluster members from field objects, and\u0000probe the main sequence (MS) of the clusters down to <0.1 $M_odot$ as well as\u0000the brighter part of the white-dwarf sequence. We show that theoretical\u0000isochrones fall short in modeling the low-mass MS and discuss possible\u0000explanations for the observed discrepancies. Our analysis suggests that the\u0000lowest-mass members of both clusters are significantly more metal-rich and\u0000oxygen-poor than their higher-mass counterparts. It is unclear whether the\u0000difference is caused by a genuine mass-dependent chemical heterogeneity,\u0000low-temperature atmospheric processes altering the observed abundances, or\u0000systematic shortcomings in the models. We computed the present-day local\u0000luminosity and mass functions of the two clusters; our data reveal a strong\u0000flattening of the mass function indicative of a significant preferential loss\u0000of low-mass stars in agreement with previous dynamical models for these two\u0000clusters. We have made our NIRISS astro-photometric catalogs and stacked images\u0000publicly available to the community.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217383","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
One month convection timescale on the surface of a giant evolved star 一颗巨型演化恒星表面的一个月对流时间尺度
Pub Date : 2024-09-10 DOI: arxiv-2409.06785
W. Vlemmings, T. Khouri, B. Bojnordi Arbab, E. De Beck, M. Maercker
The transport of energy through convection is important during many stages ofstellar evolution, and is best studied in our Sun or giant evolved stars.Features that are attributed to convection are found on the surface of massivered supergiant stars. Also for lower mass evolved stars, indications ofconvection are found, but convective timescales and sizes remain poorlyconstrained. Models indicate that convective motions are crucial for theproduction of strong winds that return the products of stellar nucleosynthesisinto the interstellar medium. Here we report a series of reconstructedinterferometric images of the surface of the evolved giant star R Doradus. Theimages reveal a stellar disc with prominent small scale features that providethe structure and motions of convection on the stellar surface. We find thatthe dominant structure size of the features on the stellar disc is$0.72pm0.05$ astronomical units (au). We measure the velocity of the surfacemotions to vary between $-18$ and $+20$ km s$^{-1}$, which means the convectivetimescale is approximately one month. This indicates a possible differencebetween the convection properties of low-mass and high-mass evolved stars.
通过对流进行能量传输在恒星演化的许多阶段都很重要,对太阳或巨型演化恒星的研究最为深入。在质量较低的演化恒星中,也发现了对流的迹象,但对流的时间尺度和大小仍然没有得到很好的约束。模型表明,对流运动是产生强风的关键,强风将恒星核合成的产物送回星际介质。在这里,我们报告了一系列对演化巨星 R Doradus 表面的干涉测量重建图像。这些图像揭示了一个具有突出小尺度特征的恒星盘,这些特征提供了恒星表面对流的结构和运动。我们发现恒星盘上特征的主要结构尺寸为0.72/pm0.05$天文单位(au)。我们测得的表面运动速度在$-18$和$+20$ km s$^{-1}$之间变化,这意味着对流时间尺度大约为一个月。这表明低质量和高 质量演化恒星的对流特性可能存在差异。
{"title":"One month convection timescale on the surface of a giant evolved star","authors":"W. Vlemmings, T. Khouri, B. Bojnordi Arbab, E. De Beck, M. Maercker","doi":"arxiv-2409.06785","DOIUrl":"https://doi.org/arxiv-2409.06785","url":null,"abstract":"The transport of energy through convection is important during many stages of\u0000stellar evolution, and is best studied in our Sun or giant evolved stars.\u0000Features that are attributed to convection are found on the surface of massive\u0000red supergiant stars. Also for lower mass evolved stars, indications of\u0000convection are found, but convective timescales and sizes remain poorly\u0000constrained. Models indicate that convective motions are crucial for the\u0000production of strong winds that return the products of stellar nucleosynthesis\u0000into the interstellar medium. Here we report a series of reconstructed\u0000interferometric images of the surface of the evolved giant star R Doradus. The\u0000images reveal a stellar disc with prominent small scale features that provide\u0000the structure and motions of convection on the stellar surface. We find that\u0000the dominant structure size of the features on the stellar disc is\u0000$0.72pm0.05$ astronomical units (au). We measure the velocity of the surface\u0000motions to vary between $-18$ and $+20$ km s$^{-1}$, which means the convective\u0000timescale is approximately one month. This indicates a possible difference\u0000between the convection properties of low-mass and high-mass evolved stars.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217382","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 Census of the beta Pic Moving Group and Other Nearby Associations with Gaia 贝塔皮克移动小组及其他与盖亚有关的邻近地区普查
Pub Date : 2024-09-09 DOI: arxiv-2409.06092
K. L. Luhman
I have used the third data release of the Gaia mission to improve thereliability and completeness of membership samples in the beta Pic moving group(BPMG) and other nearby associations with ages of 20-50 Myr (Sco Body, Carina,Columba, chi1 For, Tuc-Hor, IC 2602, IC 2391, NGC 2547). I find that Carina,Columba, and chi1 For are physically related and coeval, and that Carina is theclosest fringe of a much larger association. Similarly, Tuc-Hor and IC 2602form a coeval population that is spatially and kinematically continuous. Bothresults agree with hypotheses from Gagne et al. (2021). I have used the newcatalogs to study the associations in terms of their initial mass functions,X-ray emission, ages, and circumstellar disks. For instance, using the modelfor Li depletion from Jeffries et al. (2023), I have derived an age of24.7+0.9/-0.6 Myr for BPMG, which is similar to estimates from previousstudies. In addition, I have used infrared photometry from the Wide-fieldInfrared Survey Explorer to check for excess emission from circumstellar disksamong the members of the associations, which has resulted in a dramaticincrease in the number of known disks around M stars at ages of 30-50 Myr and asignificant improvement in measurements of excess fractions for those spectraltypes and ages. Most notably, I find that the W3 excess fraction for M0-M6initially declines with age to a minimum in BPMG <0.015), increases to amaximum in Carina/Columba chi1 For (0.041+0.009/-0.007, 34 Myr), and declinesagain in the oldest two associations (40-50 Myr). The origin of that peak andthe nature of the M dwarf disks at >20 Myr are unclear.
我利用盖亚(Gaia)任务发布的第三次数据,提高了β皮克移动群(BPMG)和其他年龄在20-50 Myr的附近星团(Sco Body、Carina、Columba、chi1 For、Tuc-Hor、IC 2602、IC 2391、NGC 2547)成员样本的可靠性和完整性。我发现船底座、哥伦布和chi1 For在物理上是相关的,而且是共生的,船底座是一个大得多的联合体的最接近的边缘。同样,Tuc-Hor 和 IC 2602 形成了一个在空间和运动学上连续的共生族群。这两个结果都与加涅等人(2021 年)的假设一致。我利用新的目录从初始质量函数、X射线发射、年龄和周星盘等方面对这些联系进行了研究。例如,利用 Jeffries 等人(2023 年)的锂耗尽模型,我推算出 BPMG 的年龄为 24.7+0.9/-0.6 Myr,这与之前研究的估计值相似。此外,我还利用宽视场红外巡天探测器(Wide-field-Infrared Survey Explorer)的红外测光来检查星团成员中是否有来自周星盘的过量发射,结果发现年龄在30-50 Myr的M星周围的已知周星盘的数量急剧增加,对这些光谱类型和年龄的过量分数的测量结果也有了显著改善。最值得注意的是,我发现M0-M6的W3过剩分率最初会随着年龄的增长而下降,到BPMG 20 Myr的最小值还不清楚。
{"title":"A Census of the beta Pic Moving Group and Other Nearby Associations with Gaia","authors":"K. L. Luhman","doi":"arxiv-2409.06092","DOIUrl":"https://doi.org/arxiv-2409.06092","url":null,"abstract":"I have used the third data release of the Gaia mission to improve the\u0000reliability and completeness of membership samples in the beta Pic moving group\u0000(BPMG) and other nearby associations with ages of 20-50 Myr (Sco Body, Carina,\u0000Columba, chi1 For, Tuc-Hor, IC 2602, IC 2391, NGC 2547). I find that Carina,\u0000Columba, and chi1 For are physically related and coeval, and that Carina is the\u0000closest fringe of a much larger association. Similarly, Tuc-Hor and IC 2602\u0000form a coeval population that is spatially and kinematically continuous. Both\u0000results agree with hypotheses from Gagne et al. (2021). I have used the new\u0000catalogs to study the associations in terms of their initial mass functions,\u0000X-ray emission, ages, and circumstellar disks. For instance, using the model\u0000for Li depletion from Jeffries et al. (2023), I have derived an age of\u000024.7+0.9/-0.6 Myr for BPMG, which is similar to estimates from previous\u0000studies. In addition, I have used infrared photometry from the Wide-field\u0000Infrared Survey Explorer to check for excess emission from circumstellar disks\u0000among the members of the associations, which has resulted in a dramatic\u0000increase in the number of known disks around M stars at ages of 30-50 Myr and a\u0000significant improvement in measurements of excess fractions for those spectral\u0000types and ages. Most notably, I find that the W3 excess fraction for M0-M6\u0000initially declines with age to a minimum in BPMG <0.015), increases to a\u0000maximum in Carina/Columba chi1 For (0.041+0.009/-0.007, 34 Myr), and declines\u0000again in the oldest two associations (40-50 Myr). The origin of that peak and\u0000the nature of the M dwarf disks at >20 Myr are unclear.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227208","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
The Role of High-mass Stellar Binaries in the Formation of High-mass Black Holes in Dense Star Clusters 高质恒星双星在密集星团中形成高质黑洞过程中的作用
Pub Date : 2024-09-09 DOI: arxiv-2409.05947
Ambreesh Khurana, Sourav Chatterjee
Recent detections of gravitational waves from mergers of binary black holes(BBHs) with pre-merger source-frame individual masses in the so-called uppermass-gap, expected due to (pulsational) pair instability supernova ((P)PISN),have created immense interest in the astrophysical production of high-massblack holes (BHs). Previous studies show that high-mass BHs may be produced viarepeated BBH mergers inside dense star clusters. Alternatively, inside densestar clusters, stars with unusually low core-to-envelope mass ratios can formvia mergers of high-mass stars, which then can avoid (P)PISN, but producehigh-mass BHs via mass fallback. We simulate detailed star-by-starmulti-physics models of dense star clusters using the Monte Carlo clusterevolution code, CMC, to investigate the role of primordial binary fractionamong high-mass stars (>=15 Msun) on the formation of high-mass BHs. We varythe high-mass stellar binary fraction (fb_15_prime) while keeping all otherinitial properties, including the population of high-mass stars, unchanged. Wefind that the number of high-mass BHs, as well as the mass of the most massiveBH formed via stellar core-collapse are proportional to fb_15_prime. Incontrast, there is no correlation between fb_15_prime and the number ofhigh-mass BHs formed via BH-BH mergers. Since the total production of high-massBHs is dominated by BH-BH mergers in old clusters, the overall number ofhigh-mass BHs produced over the typical lifetime of globular clusters isinsensitive to fb_15_prime. Furthermore, we study the differences in thedemographics of BH-BH mergers as a function of fb_15_prime.
最近探测到的双黑洞(BBHs)合并产生的引力波,其合并前源框的单个质量处于所谓的上质量间隙(uppermass-gap),预计是由于(脉冲)对不稳定性超新星((P)PISN)引起的,这引起了人们对高质黑洞(BHs)天体物理产生的极大兴趣。先前的研究表明,高质黑洞可能是通过高密度星团内部的重复BBH合并产生的。或者,在致密星团内部,内核与外壳质量比异常低的恒星可以通过高质恒星的合并形成,这样就可以避免(P)PISN,但会通过质量回落产生高质黑洞。我们使用蒙特卡罗星团演化代码 CMC 模拟了高密度星团的详细的逐星多物理模型,研究了高质恒星(>=15 Msun)中的原始双星比例对高质 BH 形成的作用。我们改变了高质恒星的双星比例(fb_15_prime),同时保持所有其他初始属性不变,包括高质恒星的数量。我们发现,高质 BH 的数量以及通过恒星核心坍缩形成的最大质量 BH 的质量与 fb_15_prime 成正比。与此相反,fb_15_prime 与通过 BH-BH 合并形成的高质 BH 的数量之间没有相关性。由于老星团中的BH-BH合并主要产生高质BH,因此在球状星团的典型生命周期中产生的高质BH的总数对fb_15_prime并不敏感。此外,我们还研究了BH-BH合并的动力学差异与fb_15_prime的函数关系。
{"title":"The Role of High-mass Stellar Binaries in the Formation of High-mass Black Holes in Dense Star Clusters","authors":"Ambreesh Khurana, Sourav Chatterjee","doi":"arxiv-2409.05947","DOIUrl":"https://doi.org/arxiv-2409.05947","url":null,"abstract":"Recent detections of gravitational waves from mergers of binary black holes\u0000(BBHs) with pre-merger source-frame individual masses in the so-called upper\u0000mass-gap, expected due to (pulsational) pair instability supernova ((P)PISN),\u0000have created immense interest in the astrophysical production of high-mass\u0000black holes (BHs). Previous studies show that high-mass BHs may be produced via\u0000repeated BBH mergers inside dense star clusters. Alternatively, inside dense\u0000star clusters, stars with unusually low core-to-envelope mass ratios can form\u0000via mergers of high-mass stars, which then can avoid (P)PISN, but produce\u0000high-mass BHs via mass fallback. We simulate detailed star-by-star\u0000multi-physics models of dense star clusters using the Monte Carlo cluster\u0000evolution code, CMC, to investigate the role of primordial binary fraction\u0000among high-mass stars (>=15 Msun) on the formation of high-mass BHs. We vary\u0000the high-mass stellar binary fraction (fb_15_prime) while keeping all other\u0000initial properties, including the population of high-mass stars, unchanged. We\u0000find that the number of high-mass BHs, as well as the mass of the most massive\u0000BH formed via stellar core-collapse are proportional to fb_15_prime. In\u0000contrast, there is no correlation between fb_15_prime and the number of\u0000high-mass BHs formed via BH-BH mergers. Since the total production of high-mass\u0000BHs is dominated by BH-BH mergers in old clusters, the overall number of\u0000high-mass BHs produced over the typical lifetime of globular clusters is\u0000insensitive to fb_15_prime. Furthermore, we study the differences in the\u0000demographics of BH-BH mergers as a function of fb_15_prime.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217389","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
Full Stokes-vector inversion of the solar Mg II h & k lines 太阳镁 II h 和 k 线的全斯托克斯向量反演
Pub Date : 2024-09-09 DOI: arxiv-2409.05328
Hao Li, Tanausú del Pino Alemán, Javier Trujillo Bueno
The polarization of the Mg II h & k resonance lines is the result of thejoint action of scattering processes and the magnetic field induced Hanle,Zeeman, and magneto-optical effects, thus holding significant potential for thediagnostic of the magnetic field in the solar chromosphere. The ChromosphericLAyer Spectro-Polarimeter sounding rocket experiment, carried out in 2019,successfully measured at each position along the 196 arcsec spectrograph slitthe wavelength variation of the four Stokes parameters in the spectral regionof this doublet around 280 nm, both in an active region plage and in a quietregion close to the limb. We consider some of these CLASP2 Stokes profiles andapply to them the recently-developed HanleRT Tenerife Inversion Code, whichassumes a one-dimensional model atmosphere for each spatial pixel underconsideration (i.e., it neglects the effects of horizontal radiative transfer).We find that the non-magnetic causes of symmetry breaking, due to thehorizontal inhomogeneities and the gradients of the horizontal components ofthe macroscopic velocity in the solar atmosphere, have a significant impact onthe linear polarization profiles. By introducing such non-magnetic causes ofsymmetry breaking as parameters in our inversion code, we can successfully fitthe Stokes profiles and provide an estimation of the magnetic field vector. Forexample, in the quiet region pixels, where no circular polarization signal isdetected, we find that the magnetic field strength in the upper chromospherevaries between 1 and 20 gauss.
Mg II h和k共振线的偏振是散射过程和磁场诱导的汉勒、泽曼和磁光效应共同作用的结果,因此在诊断太阳色球层磁场方面具有重要潜力。2019年进行的色球层激光分光极谱仪探空火箭实验在196角秒光谱仪狭缝的每个位置都成功地测量了280纳米左右该双色球光谱区域内四个斯托克斯参数的波长变化,无论是在活跃区域的平台还是在靠近边缘的安静区域。我们考虑了 CLASP2 中的一些斯托克斯剖面,并将最近开发的 HanleRT Tenerife 反演代码应用于这些剖面,该代码假定所考虑的每个空间像素都是一维模型大气(即忽略了水平辐射传递的影响)。我们发现,由于太阳大气中的水平不均匀性和宏观速度水平分量的梯度,对称性破缺的非磁性原因对线性极化剖面有重大影响。通过在反演代码中引入这些非磁性的对称性破缺原因作为参数,我们可以成功地拟合斯托克斯剖面,并提供磁场矢量的估计值。例如,在没有检测到圆极化信号的静区像素中,我们发现上色球层的磁场强度在 1 到 20 高斯之间变化。
{"title":"Full Stokes-vector inversion of the solar Mg II h & k lines","authors":"Hao Li, Tanausú del Pino Alemán, Javier Trujillo Bueno","doi":"arxiv-2409.05328","DOIUrl":"https://doi.org/arxiv-2409.05328","url":null,"abstract":"The polarization of the Mg II h & k resonance lines is the result of the\u0000joint action of scattering processes and the magnetic field induced Hanle,\u0000Zeeman, and magneto-optical effects, thus holding significant potential for the\u0000diagnostic of the magnetic field in the solar chromosphere. The Chromospheric\u0000LAyer Spectro-Polarimeter sounding rocket experiment, carried out in 2019,\u0000successfully measured at each position along the 196 arcsec spectrograph slit\u0000the wavelength variation of the four Stokes parameters in the spectral region\u0000of this doublet around 280 nm, both in an active region plage and in a quiet\u0000region close to the limb. We consider some of these CLASP2 Stokes profiles and\u0000apply to them the recently-developed HanleRT Tenerife Inversion Code, which\u0000assumes a one-dimensional model atmosphere for each spatial pixel under\u0000consideration (i.e., it neglects the effects of horizontal radiative transfer).\u0000We find that the non-magnetic causes of symmetry breaking, due to the\u0000horizontal inhomogeneities and the gradients of the horizontal components of\u0000the macroscopic velocity in the solar atmosphere, have a significant impact on\u0000the linear polarization profiles. By introducing such non-magnetic causes of\u0000symmetry breaking as parameters in our inversion code, we can successfully fit\u0000the Stokes profiles and provide an estimation of the magnetic field vector. For\u0000example, in the quiet region pixels, where no circular polarization signal is\u0000detected, we find that the magnetic field strength in the upper chromosphere\u0000varies between 1 and 20 gauss.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227211","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
Matching seismic masses for RR Lyrae-type and oscillating red horizontal-branch stars in M4 M4中RR天琴座型恒星和振荡红色水平分支恒星的匹配地震质量
Pub Date : 2024-09-09 DOI: arxiv-2409.05391
László Molnár, Henryka Netzel, Madeline Howell, Csilla Kalup, Meridith Joyce
Globular clusters offer a powerful way to test the properties of stellarpopulations and the late stages of low-mass stellar evolution. In this paper westudy oscillating giant stars and overtone RR Lyrae-type pulsators in thenearest globular cluster, M4, with the help of high-precision, continuous lightcurves collected by the Kepler space telescope in the K2 mission. We determinethe frequency composition of five RRc stars and model their physical parameterswith a grid of linear pulsation models. We are able, for the first time, tocompare seismic masses of RR Lyrae stars directly to the masses of the verysimilar red horizontal branch stars in the same stellar population,independently determined from asteroseismic scaling relations. We find a closematch, with an average seismic mass of $0.651pm0.028,M_odot$ for RR Lyraestars and $0.657pm0.034,M_odot$ for red horizontal-branch stars. While thevalidity of our RR Lyrae masses still relies on the similarity of neighboringhorizontal branch subgroups, this result strongly indicates that RRc stars mayindeed exhibit high-degree, $l = 8$ and 9 non-radial modes, and modeling thesemodes can provide realistic mass estimates. We also determine the He content ofthe cluster to be $Y = 0.266pm 0.008$, and compare the seismic masses for oursample of RR Lyrae to theoretical mass relations and highlight the limitationsof these relations.
球状星团为检验恒星群的性质和低质量恒星演化的晚期阶段提供了一种强有力的方法。本文借助开普勒太空望远镜在K2任务中收集的高精度连续光曲线,研究了距离球状星团M4最近的球状星团中的振荡巨星和泛音RR Lyrae型脉冲星。我们确定了五颗RRc恒星的频率组成,并用线性脉动模型网格来模拟它们的物理参数。我们首次能够将天琴座RR星的地震质量直接与同一恒星群中非常相似的红色水平支恒星的质量进行比较,后者是根据小行星地震比例关系独立确定的。我们发现两者的质量非常接近,RR天琴座恒星的平均地震质量为0.651/pm0.028,M_odot$,而红色水平分支恒星的平均地震质量为0.657/pm0.034,M_odot$。虽然我们的天琴座RR星质量的有效性仍然依赖于相邻水平分支亚群的相似性,但这一结果有力地表明,RRc星可能确实表现出了高阶的、$l = 8$和9的非径向模式,而这些模式的建模可以提供现实的质量估计。我们还确定了星团中的氦含量为$Y = 0.266pm 0.008$,并将我们的天琴座RR样本的地震质量与理论质量关系进行了比较,强调了这些关系的局限性。
{"title":"Matching seismic masses for RR Lyrae-type and oscillating red horizontal-branch stars in M4","authors":"László Molnár, Henryka Netzel, Madeline Howell, Csilla Kalup, Meridith Joyce","doi":"arxiv-2409.05391","DOIUrl":"https://doi.org/arxiv-2409.05391","url":null,"abstract":"Globular clusters offer a powerful way to test the properties of stellar\u0000populations and the late stages of low-mass stellar evolution. In this paper we\u0000study oscillating giant stars and overtone RR Lyrae-type pulsators in the\u0000nearest globular cluster, M4, with the help of high-precision, continuous light\u0000curves collected by the Kepler space telescope in the K2 mission. We determine\u0000the frequency composition of five RRc stars and model their physical parameters\u0000with a grid of linear pulsation models. We are able, for the first time, to\u0000compare seismic masses of RR Lyrae stars directly to the masses of the very\u0000similar red horizontal branch stars in the same stellar population,\u0000independently determined from asteroseismic scaling relations. We find a close\u0000match, with an average seismic mass of $0.651pm0.028,M_odot$ for RR Lyrae\u0000stars and $0.657pm0.034,M_odot$ for red horizontal-branch stars. While the\u0000validity of our RR Lyrae masses still relies on the similarity of neighboring\u0000horizontal branch subgroups, this result strongly indicates that RRc stars may\u0000indeed exhibit high-degree, $l = 8$ and 9 non-radial modes, and modeling these\u0000modes can provide realistic mass estimates. We also determine the He content of\u0000the cluster to be $Y = 0.266pm 0.008$, and compare the seismic masses for our\u0000sample of RR Lyrae to theoretical mass relations and highlight the limitations\u0000of these relations.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217411","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
Gemini High-resolution Optical SpecTrograph (GHOST) at Gemini-South: Instrument performance and integration, first science, and next steps 位于双子座南区的双子座高分辨率光学摄谱仪(GHOST):仪器性能和集成、首次科学实验以及下一步工作
Pub Date : 2024-09-09 DOI: arxiv-2409.05855
V. M. Kalari, R. J. Diaz, G. Robertson, A. McConnachie, M. Ireland, R. Salinas, P. Young, C. Simpson, C. Hayes, J. Nielsen, G. Burley, J. Pazder, M. Gomez-Jimenez, E. Martioli, S. B. Howell, M. Jeong, S. Juneau, R. Ruiz-Carmona, S. Margheim, A. Sheinis, A. Anthony, G. Baker, T. A. M. Berg, T. Cao, E. Chapin, T. Chin, K. Chiboucas, V. Churilov, E. Deibert, A. Densmore, J. Dunn, M. L. Edgar, J. Heo, D. Henderson, T. Farrell, J. Font, V. Firpo, J. Fuentes, K. Labrie, S. Lambert, J. Lawrence, J. Lothrop, R. McDermid, B. W. Miller, G. Perez, V. M. Placco, P. Prado, C. Quiroz, F. Ramos, R. Rutten, K. M. G. Silva, J. Thomas-Osip, C. Urrutia, W. D. Vacca, K. Venn, F. Waller, L. Waller, M. White, S. Xu, R. Zhelem
The Gemini South telescope is now equipped with a new high-resolutionspectrograph called GHOST (the Gemini High-resolution Optical SpecTrograph).This instrument provides high-efficiency, high-resolution spectra covering347-1060 nm in a single exposure of either one or two targets simultaneously,along with precision radial velocity spectroscopy utilizing an internalcalibration source. It can operate at a spectral element resolving power ofeither 76000 or 56000, and can reach a SNR$sim$5 in a 1hr exposure on aV$sim$20.8 mag target in median site seeing, and dark skies (per resolutionelement). GHOST was installed on-site in June 2022, and we report performanceafter full integration to queue operations in November 2023, in addition toscientific results enabled by the integration observing runs. These resultsdemonstrate the ability to observe a wide variety of bright and faint targetswith high efficiency and precision. With GHOST, new avenues to explorehigh-resolution spectroscopy have opened up to the astronomical community.These are described, along with the planned and potential upgrades to theinstrument.
双子座南望远镜现在配备了一台名为 GHOST(双子座高分辨率光学摄谱仪)的新型高分辨率摄谱仪。这台仪器可以在一次曝光中同时对一个或两个目标提供覆盖 347-1060 纳米的高效率、高分辨率光谱,并利用内部校准源进行精确的径向速度光谱分析。它可以在 76000 或 56000 分 辨率的光谱元件分辨率下运行,在中值视场和暗天条件下,对 20.8 等的目标进行 1 小时的曝光,信噪比可达到 5(每个分辨率元件)。GHOST于2022年6月在现场安装,我们报告了2023年11月完全整合到队列运行之后的性能,以及整合观测运行所取得的科学结果。这些结果展示了以高效率和高精度观测各种亮目标和暗目标的能力。GHOST 为天文学界开辟了探索高分辨率光谱的新途径。
{"title":"Gemini High-resolution Optical SpecTrograph (GHOST) at Gemini-South: Instrument performance and integration, first science, and next steps","authors":"V. M. Kalari, R. J. Diaz, G. Robertson, A. McConnachie, M. Ireland, R. Salinas, P. Young, C. Simpson, C. Hayes, J. Nielsen, G. Burley, J. Pazder, M. Gomez-Jimenez, E. Martioli, S. B. Howell, M. Jeong, S. Juneau, R. Ruiz-Carmona, S. Margheim, A. Sheinis, A. Anthony, G. Baker, T. A. M. Berg, T. Cao, E. Chapin, T. Chin, K. Chiboucas, V. Churilov, E. Deibert, A. Densmore, J. Dunn, M. L. Edgar, J. Heo, D. Henderson, T. Farrell, J. Font, V. Firpo, J. Fuentes, K. Labrie, S. Lambert, J. Lawrence, J. Lothrop, R. McDermid, B. W. Miller, G. Perez, V. M. Placco, P. Prado, C. Quiroz, F. Ramos, R. Rutten, K. M. G. Silva, J. Thomas-Osip, C. Urrutia, W. D. Vacca, K. Venn, F. Waller, L. Waller, M. White, S. Xu, R. Zhelem","doi":"arxiv-2409.05855","DOIUrl":"https://doi.org/arxiv-2409.05855","url":null,"abstract":"The Gemini South telescope is now equipped with a new high-resolution\u0000spectrograph called GHOST (the Gemini High-resolution Optical SpecTrograph).\u0000This instrument provides high-efficiency, high-resolution spectra covering\u0000347-1060 nm in a single exposure of either one or two targets simultaneously,\u0000along with precision radial velocity spectroscopy utilizing an internal\u0000calibration source. It can operate at a spectral element resolving power of\u0000either 76000 or 56000, and can reach a SNR$sim$5 in a 1hr exposure on a\u0000V$sim$20.8 mag target in median site seeing, and dark skies (per resolution\u0000element). GHOST was installed on-site in June 2022, and we report performance\u0000after full integration to queue operations in November 2023, in addition to\u0000scientific results enabled by the integration observing runs. These results\u0000demonstrate the ability to observe a wide variety of bright and faint targets\u0000with high efficiency and precision. With GHOST, new avenues to explore\u0000high-resolution spectroscopy have opened up to the astronomical community.\u0000These are described, along with the planned and potential upgrades to the\u0000instrument.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227215","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
Connectivity between the solar photosphere and chromosphere in a vortical structure. Observations of multi-phase, small-scale magnetic field amplification 涡旋结构中太阳光层和色球层之间的联系。多相小尺度磁场放大观测
Pub Date : 2024-09-09 DOI: arxiv-2409.05769
S. M. Díaz-Castillo, C. E. Fischer, R. Rezaei, O. Steiner, S. Berdyugina
High-resolution solar observations have revealed the existence of small-scalevortices, as seen in chromospheric intensity maps and velocity diagnostics.Frequently, these vortices have been observed near magnetic fluxconcentrations, indicating a link between swirls and the evolution of thesmall-scale magnetic fields. Vortices have also been studied withmagneto-hydrodynamic (MHD) numerical simulations of the solar atmosphere,revealing their complexity, dynamics, and magnetic nature. In particular, ithas been proposed that a rotating magnetic field structure driven by aphotospheric vortex flow at its footprint produces the chromospheric swirlingplasma motion. We present a complete and comprehensive description of the timeevolution of a small-scale magnetic flux concentration interacting with theintergranular vortex flow and affected by processes of intensification andweakening of its magnetic field. In addition, we study the chromosphericdynamics associated with the interaction, including the analysis of achromospheric swirl and an impulsive chromospheric jet.
高分辨率太阳观测揭示了小尺度漩涡的存在,正如在色球强度图和速度诊断中看到的那样,这些漩涡经常在磁通量集中附近被观测到,表明漩涡与小尺度磁场的演变之间存在联系。我们还利用太阳大气的磁流体动力(MHD)数值模拟对漩涡进行了研究,揭示了它们的复杂性、动力学和磁性。特别是,有人提出,由光球漩涡流驱动的旋转磁场结构在其足迹处产生了色球层漩涡等离子体运动。我们完整而全面地描述了与晶间漩涡流相互作用并受其磁场增强和减弱过程影响的小尺度磁通量浓度的时间演变。此外,我们还研究了与相互作用相关的色球层动力学,包括分析非色球层漩涡和脉冲色球层射流。
{"title":"Connectivity between the solar photosphere and chromosphere in a vortical structure. Observations of multi-phase, small-scale magnetic field amplification","authors":"S. M. Díaz-Castillo, C. E. Fischer, R. Rezaei, O. Steiner, S. Berdyugina","doi":"arxiv-2409.05769","DOIUrl":"https://doi.org/arxiv-2409.05769","url":null,"abstract":"High-resolution solar observations have revealed the existence of small-scale\u0000vortices, as seen in chromospheric intensity maps and velocity diagnostics.\u0000Frequently, these vortices have been observed near magnetic flux\u0000concentrations, indicating a link between swirls and the evolution of the\u0000small-scale magnetic fields. Vortices have also been studied with\u0000magneto-hydrodynamic (MHD) numerical simulations of the solar atmosphere,\u0000revealing their complexity, dynamics, and magnetic nature. In particular, it\u0000has been proposed that a rotating magnetic field structure driven by a\u0000photospheric vortex flow at its footprint produces the chromospheric swirling\u0000plasma motion. We present a complete and comprehensive description of the time\u0000evolution of a small-scale magnetic flux concentration interacting with the\u0000intergranular vortex flow and affected by processes of intensification and\u0000weakening of its magnetic field. In addition, we study the chromospheric\u0000dynamics associated with the interaction, including the analysis of a\u0000chromospheric swirl and an impulsive chromospheric jet.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217409","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
High-Speed Outflows and Dusty Disks during the AGB to PN Transition: The PANORAMA survey AGB向PN过渡期间的高速外流和尘状盘:PANORAMA 勘测
Pub Date : 2024-09-09 DOI: arxiv-2409.06038
Raghvendra Sahai, Javier Alcolea, Bruce Balick, Eric G. Blackman, Valentin Bujarrabal, Arancha Castro-Carrizo, Orsola De Marco, Joel Kastner, Hyosun Kim, Eric Lagadec, Chin-Fei Lee, Laurence Sabin, M. Santander-Garcia, Carmen Sánchez Contreras, Daniel Tafoya, Toshiya Ueta, Wouter Vlemmings, Albert Zijlstra
As mass-losing asymptotic giant branch (AGB) stars evolve to planetarynebulae (PNe), the mass outflow geometries transform from nearly spherical toextreme aspherical. The physical mechanisms governing this transformation arewidely believed to be linked to binarity and the associated production of disksand fast jets during transitional (post-AGB) evolutionary stages. We arecarrying out a systematic ALMA survey ($P$re-planet$A$ry $N$ebulaehigh-angular-res$O$lution su$R$vey with $A$L$MA$ or PANORAMA) of arepresentative sample of bipolar and multipolar post-AGB objects. We haveobtained high angular-resolution (0".1-0".4) observations of the CO(3--2)and/or 6--5 emission in order to probe the spatio-kinematic structure of thecollimated outflows and the central disk/torii. The results are remarkable,generally showing the presence of bipolar or multipolar high-velocity outflows,dense toroidal waists, and in one case, a geometrically-thin circular ringaround the central bipolar nebula. A high degree of point-symmetrycharacterizes the morphology of the mass ejecta. In this contribution, wepresent these and other highlights from our survey. We aim to use 2D/3Dradiative transfer modeling in order to derive accurate outflow momenta, massesand mass-loss rates for our sample, and build hydrodynamical models that canexplain the observed spatio-kinematic structures. These results will then beused to distinguish between different classes of PN-shaping binary interactionmodels.
当质量损失的渐变巨枝(AGB)恒星演化成行星状星云(PNe)时,质量流出的几何形状会从近似球形转变为极端非球形。人们普遍认为这种转变的物理机制与二元性以及在过渡(后AGB)演化阶段产生的相关磁盘和快速喷流有关。我们正在对具有代表性的双极和多极后AGB天体样本进行系统的ALMA巡天(P$re-planet$A$ry $N$ebulaehigh-angular-res$O$lution su$R$vey with $A$L$MA$ or PANORAMA)。我们获得了 CO(3--2)和/或 6--5 辐射的高角分辨率(0".1-0".4)观测数据,以探测共轭外流和中心盘/蝶形的空间运动结构。结果非常显著,一般都显示出存在双极或多极高速外流和致密的环状腰带,在一个情况下,中央双极星云周围还有一个几何上很薄的圆形环。质量喷出物的形态具有高度的点对称性。在本文中,我们将介绍这些以及我们的观测中发现的其他亮点。我们的目标是利用二维/三维辐射传递建模,为我们的样本推导出精确的流出矩、质量和质量损失率,并建立能够解释观测到的空间运动学结构的流体力学模型。然后将利用这些结果来区分不同类别的 PN 塑造双星相互作用模型。
{"title":"High-Speed Outflows and Dusty Disks during the AGB to PN Transition: The PANORAMA survey","authors":"Raghvendra Sahai, Javier Alcolea, Bruce Balick, Eric G. Blackman, Valentin Bujarrabal, Arancha Castro-Carrizo, Orsola De Marco, Joel Kastner, Hyosun Kim, Eric Lagadec, Chin-Fei Lee, Laurence Sabin, M. Santander-Garcia, Carmen Sánchez Contreras, Daniel Tafoya, Toshiya Ueta, Wouter Vlemmings, Albert Zijlstra","doi":"arxiv-2409.06038","DOIUrl":"https://doi.org/arxiv-2409.06038","url":null,"abstract":"As mass-losing asymptotic giant branch (AGB) stars evolve to planetary\u0000nebulae (PNe), the mass outflow geometries transform from nearly spherical to\u0000extreme aspherical. The physical mechanisms governing this transformation are\u0000widely believed to be linked to binarity and the associated production of disks\u0000and fast jets during transitional (post-AGB) evolutionary stages. We are\u0000carrying out a systematic ALMA survey ($P$re-planet$A$ry $N$ebulae\u0000high-angular-res$O$lution su$R$vey with $A$L$MA$ or PANORAMA) of a\u0000representative sample of bipolar and multipolar post-AGB objects. We have\u0000obtained high angular-resolution (0\".1-0\".4) observations of the CO(3--2)\u0000and/or 6--5 emission in order to probe the spatio-kinematic structure of the\u0000collimated outflows and the central disk/torii. The results are remarkable,\u0000generally showing the presence of bipolar or multipolar high-velocity outflows,\u0000dense toroidal waists, and in one case, a geometrically-thin circular ring\u0000around the central bipolar nebula. A high degree of point-symmetry\u0000characterizes the morphology of the mass ejecta. In this contribution, we\u0000present these and other highlights from our survey. We aim to use 2D/3D\u0000radiative transfer modeling in order to derive accurate outflow momenta, masses\u0000and mass-loss rates for our sample, and build hydrodynamical models that can\u0000explain the observed spatio-kinematic structures. These results will then be\u0000used to distinguish between different classes of PN-shaping binary interaction\u0000models.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217388","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
Advancing Machine Learning for Stellar Activity and Exoplanet Period Rotation 推进恒星活动和系外行星周期旋转的机器学习
Pub Date : 2024-09-09 DOI: arxiv-2409.05482
Fatemeh Fazel Hesar, Bernard Foing, Ana M. Heras, Mojtaba Raouf, Victoria Foing, Shima Javanmardi, Fons J. Verbeek
This study applied machine learning models to estimate stellar rotationperiods from corrected light curve data obtained by the NASA Kepler mission.Traditional methods often struggle to estimate rotation periods accurately dueto noise and variability in the light curve data. The workflow involved usinginitial period estimates from the LS-Periodogram and Transit Least Squarestechniques, followed by splitting the data into training, validation, andtesting sets. We employed several machine learning algorithms, includingDecision Tree, Random Forest, K-Nearest Neighbors, and Gradient Boosting, andalso utilized a Voting Ensemble approach to improve prediction accuracy androbustness. The analysis included data from multiple Kepler IDs, providing detailedmetrics on orbital periods and planet radii. Performance evaluation showed thatthe Voting Ensemble model yielded the most accurate results, with an RMSEapproximately 50% lower than the Decision Tree model and 17% better than theK-Nearest Neighbors model. The Random Forest model performed comparably to theVoting Ensemble, indicating high accuracy. In contrast, the Gradient Boostingmodel exhibited a worse RMSE compared to the other approaches. Comparisons ofthe predicted rotation periods to the photometric reference periods showedclose alignment, suggesting the machine learning models achieved highprediction accuracy. The results indicate that machine learning, particularlyensemble methods, can effectively solve the problem of accurately estimatingstellar rotation periods, with significant implications for advancing the studyof exoplanets and stellar astrophysics.
这项研究应用机器学习模型从美国宇航局开普勒任务获得的校正光曲线数据中估算恒星的自转周期。工作流程包括使用 LS-Periodogram 和 Transit Least Squarestechniques 得出的初始周期估计值,然后将数据分成训练集、验证集和测试集。我们使用了几种机器学习算法,包括决策树、随机森林、K-近邻和梯度提升,还使用了投票集合方法来提高预测准确性和稳健性。分析包括来自多个开普勒 ID 的数据,提供了轨道周期和行星半径的详细指标。性能评估结果表明,投票集合模型产生了最准确的结果,其均方误差比决策树模型低约50%,比K-近邻模型好17%。随机森林模型的表现与投票集合模型相当,显示出较高的准确性。相比之下,梯度提升模型的均方根误差比其他方法要小。预测的旋转周期与光度参考周期的比较显示两者接近,表明机器学习模型达到了较高的预测精度。结果表明,机器学习,尤其是集合方法,可以有效地解决准确估计恒星旋转周期的问题,对推动系外行星和恒星天体物理学的研究具有重要意义。
{"title":"Advancing Machine Learning for Stellar Activity and Exoplanet Period Rotation","authors":"Fatemeh Fazel Hesar, Bernard Foing, Ana M. Heras, Mojtaba Raouf, Victoria Foing, Shima Javanmardi, Fons J. Verbeek","doi":"arxiv-2409.05482","DOIUrl":"https://doi.org/arxiv-2409.05482","url":null,"abstract":"This study applied machine learning models to estimate stellar rotation\u0000periods from corrected light curve data obtained by the NASA Kepler mission.\u0000Traditional methods often struggle to estimate rotation periods accurately due\u0000to noise and variability in the light curve data. The workflow involved using\u0000initial period estimates from the LS-Periodogram and Transit Least Squares\u0000techniques, followed by splitting the data into training, validation, and\u0000testing sets. We employed several machine learning algorithms, including\u0000Decision Tree, Random Forest, K-Nearest Neighbors, and Gradient Boosting, and\u0000also utilized a Voting Ensemble approach to improve prediction accuracy and\u0000robustness. The analysis included data from multiple Kepler IDs, providing detailed\u0000metrics on orbital periods and planet radii. Performance evaluation showed that\u0000the Voting Ensemble model yielded the most accurate results, with an RMSE\u0000approximately 50% lower than the Decision Tree model and 17% better than the\u0000K-Nearest Neighbors model. The Random Forest model performed comparably to the\u0000Voting Ensemble, indicating high accuracy. In contrast, the Gradient Boosting\u0000model exhibited a worse RMSE compared to the other approaches. Comparisons of\u0000the predicted rotation periods to the photometric reference periods showed\u0000close alignment, suggesting the machine learning models achieved high\u0000prediction accuracy. The results indicate that machine learning, particularly\u0000ensemble methods, can effectively solve the problem of accurately estimating\u0000stellar rotation periods, with significant implications for advancing the study\u0000of exoplanets and stellar astrophysics.","PeriodicalId":501068,"journal":{"name":"arXiv - PHYS - Solar and Stellar Astrophysics","volume":"59 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142217410","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
期刊
arXiv - PHYS - Solar and Stellar Astrophysics
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1