Pub Date : 2024-11-26DOI: 10.3847/1538-4357/ad8915
Elspeth K. H. Lee, Shang-Min Tsai, Julianne I. Moses, John M. C. Plane, Channon Visscher and Stephen J. Klippenstein
Due to the detection of phosphine (PH3) in the solar system gas giants Jupiter and Saturn, PH3 has long been suggested to be detectable in exosolar substellar atmospheres too. However, to date, direct detection of phosphine has proven to be elusive in exoplanet atmosphere surveys. We construct an updated phosphorus-hydrogen-oxygen (PHO) photochemical network suitable for the simulation of gas giant hydrogen-dominated atmospheres. Using this network, we examine PHO photochemistry in hot Jupiter and warm Neptune exoplanet atmospheres at solar and enriched metallicities. Our results show for HD 189733b-like hot Jupiters that HOPO, PO, and P2 are typically the dominant P carriers at pressures important for transit and emission spectra, rather than PH3. For GJ1214b-like warm Neptune atmospheres our results suggest that at solar metallicity PH3 is dominant in the absence of photochemistry, but is generally not in high abundance for all other chemical environments. At 10 and 100 times solar, small oxygenated phosphorus molecules such as HOPO and PO dominate for both thermochemical and photochemical simulations. The network is able to reproduce well the observed PH3 abundances on Jupiter and Saturn. Despite progress in improving the accuracy of the PHO network, large portions of the reaction rate data remain with approximate, uncertain, or missing values, which could change the conclusions of the current study significantly. Improving understanding of the kinetics of phosphorus-bearing chemical reactions will be a key undertaking for astronomers aiming to detect phosphine and other phosphorus species in both rocky and gaseous exoplanetary atmospheres in the near future.
由于在太阳系气态巨行星木星和土星中探测到了磷化氢（PH3），人们一直认为在太阳系外的亚恒星大气中也能探测到磷化氢。然而，迄今为止，在系外行星大气探测中直接探测到磷化氢还很难。我们构建了一个更新的磷-氢-氧（PHO）光化学网络，适用于模拟气态巨行星氢为主的大气。利用这个网络，我们研究了太阳和富金属性下热木星和暖海王星系外行星大气中的磷-氢-氧光化学。我们的研究结果表明，对于类似 HD 189733b 的热木星，在对过境和发射光谱有重要影响的压力下，HOPO、PO 和 P2 通常是主要的 P 载流子，而不是 PH3。对于类似 GJ1214b 的暖海王星大气，我们的研究结果表明，在太阳金属性条件下，PH3 在没有光化学作用的情况下占主导地位，但在所有其他化学环境下，PH3 的丰度通常不高。在 10 倍和 100 倍太阳亮度时，热化学和光化学模拟都以 HOPO 和 PO 等含氧磷小分子为主。该网络能够很好地再现木星和土星上观测到的 PH3 丰度。尽管在提高 PHO 网络的准确性方面取得了进展，但大部分反应速率数据仍然是近似值、不确定值或缺失值，这可能会极大地改变当前研究的结论。天文学家的目标是在不久的将来探测岩石和气态系外行星大气中的磷和其他磷物种，而加深对含磷化学反应动力学的了解将是一项关键工作。
{"title":"A Photochemical Phosphorus-Hydrogen-Oxygen Network for Hydrogen-dominated Exoplanet Atmospheres","authors":"Elspeth K. H. Lee, Shang-Min Tsai, Julianne I. Moses, John M. C. Plane, Channon Visscher and Stephen J. Klippenstein","doi":"10.3847/1538-4357/ad8915","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8915","url":null,"abstract":"Due to the detection of phosphine (PH3) in the solar system gas giants Jupiter and Saturn, PH3 has long been suggested to be detectable in exosolar substellar atmospheres too. However, to date, direct detection of phosphine has proven to be elusive in exoplanet atmosphere surveys. We construct an updated phosphorus-hydrogen-oxygen (PHO) photochemical network suitable for the simulation of gas giant hydrogen-dominated atmospheres. Using this network, we examine PHO photochemistry in hot Jupiter and warm Neptune exoplanet atmospheres at solar and enriched metallicities. Our results show for HD 189733b-like hot Jupiters that HOPO, PO, and P2 are typically the dominant P carriers at pressures important for transit and emission spectra, rather than PH3. For GJ1214b-like warm Neptune atmospheres our results suggest that at solar metallicity PH3 is dominant in the absence of photochemistry, but is generally not in high abundance for all other chemical environments. At 10 and 100 times solar, small oxygenated phosphorus molecules such as HOPO and PO dominate for both thermochemical and photochemical simulations. The network is able to reproduce well the observed PH3 abundances on Jupiter and Saturn. Despite progress in improving the accuracy of the PHO network, large portions of the reaction rate data remain with approximate, uncertain, or missing values, which could change the conclusions of the current study significantly. Improving understanding of the kinetics of phosphorus-bearing chemical reactions will be a key undertaking for astronomers aiming to detect phosphine and other phosphorus species in both rocky and gaseous exoplanetary atmospheres in the near future.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713026","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}
Pub Date : 2024-11-26DOI: 10.3847/1538-4357/ad8922
Charlotte Myers, Kishalay De, Lin Yan, Jacob E. Jencson, Nicholas Earley, Christoffer Fremling, Daichi Hiramatsu, Mansi M. Kasliwal, Ryan M. Lau, Morgan MacLeod, Megan Masterson, Christos Panagiotou, Robert Simcoe and Samaporn Tinyanont
While core-collapse supernovae (SNe) often show early and consistent signs of circumstellar medium (CSM) interaction, some exhibit delayed signatures due to interaction with distant material around the progenitor star. Here we present the discovery in NEOWISE data of WTP 19aalnxx, a luminous mid-infrared (MIR) transient in the outskirts of the galaxy KUG 0022-007 at ≈190 Mpc. First detected in 2018, WTP 19aalnxx reaches a peak absolute (Vega) magnitude of ≈−22 at 4.6 μm in ≈3 yr, comparable to the most luminous interacting SNe. Archival data reveal a ≳5× fainter optical counterpart detected since 2015, while follow-up near-infrared observations in 2022 reveal an extremely red (Ks − W2 ≈ 3.7 mag) active transient. Deep optical spectroscopy confirm strong CSM interaction signatures via intermediate-width Balmer emission lines and coronal metal lines. Modeling the broadband spectral energy distribution, we estimate the presence of ≳10−2M⊙ of warm dust, likely formed in the cold dense shell. Together with the lack of nebular Fe emission, we suggest that WTP 19aalnxx is a missed, low (optical) luminosity SN in an emerging family of core-collapse SNe distinguished by their CSM-interaction-powered MIR emission that outshines the optical bands. Investigating the Zwicky Transient Facility sample of SNe with NEOWISE data, we find 16 core-collapse SNe (≳3% in a volume-limited sample) without early signs of CSM interaction that exhibit delayed IR brightening, suggestive of dense CSM shells at ≲1017 cm. We suggest that synoptic IR surveys offer a new route to revealing late-time CSM interaction and the prevalence of intense terminal mass loss in massive stars.
{"title":"WTP 19aalnxx: Discovery of a Bright Mid-infrared Transient in the Emerging Class of Low-luminosity Supernovae Revealed by Delayed Circumstellar Interaction","authors":"Charlotte Myers, Kishalay De, Lin Yan, Jacob E. Jencson, Nicholas Earley, Christoffer Fremling, Daichi Hiramatsu, Mansi M. Kasliwal, Ryan M. Lau, Morgan MacLeod, Megan Masterson, Christos Panagiotou, Robert Simcoe and Samaporn Tinyanont","doi":"10.3847/1538-4357/ad8922","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8922","url":null,"abstract":"While core-collapse supernovae (SNe) often show early and consistent signs of circumstellar medium (CSM) interaction, some exhibit delayed signatures due to interaction with distant material around the progenitor star. Here we present the discovery in NEOWISE data of WTP 19aalnxx, a luminous mid-infrared (MIR) transient in the outskirts of the galaxy KUG 0022-007 at ≈190 Mpc. First detected in 2018, WTP 19aalnxx reaches a peak absolute (Vega) magnitude of ≈−22 at 4.6 μm in ≈3 yr, comparable to the most luminous interacting SNe. Archival data reveal a ≳5× fainter optical counterpart detected since 2015, while follow-up near-infrared observations in 2022 reveal an extremely red (Ks − W2 ≈ 3.7 mag) active transient. Deep optical spectroscopy confirm strong CSM interaction signatures via intermediate-width Balmer emission lines and coronal metal lines. Modeling the broadband spectral energy distribution, we estimate the presence of ≳10−2M⊙ of warm dust, likely formed in the cold dense shell. Together with the lack of nebular Fe emission, we suggest that WTP 19aalnxx is a missed, low (optical) luminosity SN in an emerging family of core-collapse SNe distinguished by their CSM-interaction-powered MIR emission that outshines the optical bands. Investigating the Zwicky Transient Facility sample of SNe with NEOWISE data, we find 16 core-collapse SNe (≳3% in a volume-limited sample) without early signs of CSM interaction that exhibit delayed IR brightening, suggestive of dense CSM shells at ≲1017 cm. We suggest that synoptic IR surveys offer a new route to revealing late-time CSM interaction and the prevalence of intense terminal mass loss in massive stars.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"257 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713024","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}
Pub Date : 2024-11-26DOI: 10.3847/1538-4357/ad8560
Eduard P. Kontar, Francesco Azzollini and Olena Lyubchyk
Electrons accelerated by solar flares and observed as type III solar radio bursts are not only a crucial diagnostic tool for understanding electron transport in the inner heliosphere but also a possible early indication of potentially hazardous space weather events. The electron beams traveling in the solar corona and heliosphere along magnetic field lines generate Langmuir waves and quasilinearly relax toward a plateau in velocity space. The relaxation of the electron beam over the short distance in contrast to large beam-travel distances observed is often referred to as Sturrok’s dilemma. Here, we develop a new electron transport model with quasilinear distance/time self-consistently changing in space and time. This model results in a nonlinear advection-diffusion equation for the electron beam density with a nonlinear diffusion term that is inversely proportional to the beam density. The solution predicts slow super-diffusive (ballistic) spatial expansion of a fast-propagating electron beam. This model also provides the evolution of the spectral energy density of Langmuir waves, which determines brightness temperature of plasma radiation in solar bursts. The model solution is consistent with the results of numerical simulation using kinetic equations and can explain some characteristics of type III solar radio bursts.
太阳耀斑加速的电子和观测到的III型太阳射电暴不仅是了解内日光层电子传输的重要诊断工具，而且可能是潜在危险空间天气事件的早期征兆。电子束在日冕和日光层中沿磁场线运动时会产生朗缪尔波，并在速度空间中向高原方向发生类线性弛豫。电子束在短距离内的弛豫与观测到的大束流距离形成鲜明对比，这通常被称为 "Sturrok困境"。在这里，我们建立了一个新的电子传输模型，该模型具有在空间和时间上自洽变化的准线性距离/时间。该模型的结果是电子束密度的非线性平流-扩散方程，其中的非线性扩散项与电子束密度成反比。解法预测了快速传播电子束的缓慢超扩散（弹道）空间扩展。该模型还提供了朗缪尔波频谱能量密度的演变，而朗缪尔波频谱能量密度决定了太阳爆发中等离子体辐射的亮度温度。模型解与使用动力学方程进行数值模拟的结果一致，可以解释 III 型太阳射电暴的一些特征。
{"title":"Advection-nonlinear-diffusion Model of Flare Accelerated Electron Transport in Type III Solar Radio Bursts","authors":"Eduard P. Kontar, Francesco Azzollini and Olena Lyubchyk","doi":"10.3847/1538-4357/ad8560","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8560","url":null,"abstract":"Electrons accelerated by solar flares and observed as type III solar radio bursts are not only a crucial diagnostic tool for understanding electron transport in the inner heliosphere but also a possible early indication of potentially hazardous space weather events. The electron beams traveling in the solar corona and heliosphere along magnetic field lines generate Langmuir waves and quasilinearly relax toward a plateau in velocity space. The relaxation of the electron beam over the short distance in contrast to large beam-travel distances observed is often referred to as Sturrok’s dilemma. Here, we develop a new electron transport model with quasilinear distance/time self-consistently changing in space and time. This model results in a nonlinear advection-diffusion equation for the electron beam density with a nonlinear diffusion term that is inversely proportional to the beam density. The solution predicts slow super-diffusive (ballistic) spatial expansion of a fast-propagating electron beam. This model also provides the evolution of the spectral energy density of Langmuir waves, which determines brightness temperature of plasma radiation in solar bursts. The model solution is consistent with the results of numerical simulation using kinetic equations and can explain some characteristics of type III solar radio bursts.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713023","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}
Pub Date : 2024-11-26DOI: 10.3847/1538-4357/ad83d5
Emilia Vlahos, Yayaati Chachan, Vincent Savignac and Eve J. Lee
The atmospheric composition of exoplanets is often considered as a probe of the planet’s formation conditions. How exactly the initial chemical memory may be altered from the birth to the final state of the planet, however, remains unknown. Here, we develop a simple model of pollution of planetary atmosphere by the vaporization of infalling planetesimals of varying sizes and composition (SiO2 inside 1 au and H2O outside 1 au), following their trajectory and thermal evolution through the upper advective and radiative layers of a sub-Neptune-class planet during the late stage of disk evolution. We vary the rate of pollution by changing the solid content of the disk and by dialing the level of disk gas depletion, which in turn determines the rate of planetary migration. We find that pollution by silicate grains will always be limited by the saturation limit set by the thermal state of the atmosphere. By contrast, pollution by water ice can lead to ∼2–4 orders of magnitude variation in the atmospheric water mass fraction depending on the solid and gas content of the disk. Both cases suggest that post-formation pollution can erase the initial compositional memory of formation. Post-formation pollution can potentially transform sub-Neptunes with H/He-dominated envelopes that initially formed beyond the ice line to water worlds (i.e., with a water-enriched envelope) when the disk gas is depleted by ≳2 orders of magnitude, allowing gentle migration. We additionally discuss the expected C/O ratio profile under pollution by water and refractory carbon species.
系外行星的大气成分通常被认为是行星形成条件的探测器。然而，从行星诞生到最终状态，最初的化学记忆究竟是如何改变的，仍然是未知数。在这里，我们建立了一个行星大气污染的简单模型，即不同大小和成分（1 au 内的 SiO2 和 1 au 外的 H2O）的下沉行星微粒汽化对行星大气的污染，跟踪它们在盘演化晚期穿过亚海王星级行星上层平流层和辐射层的轨迹和热演化。我们通过改变星盘的固体含量和调整星盘气体耗竭水平来改变污染率，这反过来又决定了行星的迁移率。我们发现，硅酸盐颗粒的污染总是受到大气热状态所设定的饱和极限的限制。相比之下，水冰的污染会导致大气中水的质量分数发生 2-4 个数量级的变化，这取决于星盘的固体和气体含量。这两种情况都表明，形成后的污染可以抹去形成时的初始成分记忆。形成后的污染有可能使最初在冰线以外形成的、具有H/He为主包层的亚海王星转变为水世界（即具有富水包层），此时圆盘气体耗尽了≳2个数量级，从而使迁移变得平缓。我们还讨论了在水和难熔碳物种污染下的预期 C/O 比率曲线。
{"title":"Impacting Atmospheres: How Late-stage Pollution Alters Exoplanet Composition","authors":"Emilia Vlahos, Yayaati Chachan, Vincent Savignac and Eve J. Lee","doi":"10.3847/1538-4357/ad83d5","DOIUrl":"https://doi.org/10.3847/1538-4357/ad83d5","url":null,"abstract":"The atmospheric composition of exoplanets is often considered as a probe of the planet’s formation conditions. How exactly the initial chemical memory may be altered from the birth to the final state of the planet, however, remains unknown. Here, we develop a simple model of pollution of planetary atmosphere by the vaporization of infalling planetesimals of varying sizes and composition (SiO2 inside 1 au and H2O outside 1 au), following their trajectory and thermal evolution through the upper advective and radiative layers of a sub-Neptune-class planet during the late stage of disk evolution. We vary the rate of pollution by changing the solid content of the disk and by dialing the level of disk gas depletion, which in turn determines the rate of planetary migration. We find that pollution by silicate grains will always be limited by the saturation limit set by the thermal state of the atmosphere. By contrast, pollution by water ice can lead to ∼2–4 orders of magnitude variation in the atmospheric water mass fraction depending on the solid and gas content of the disk. Both cases suggest that post-formation pollution can erase the initial compositional memory of formation. Post-formation pollution can potentially transform sub-Neptunes with H/He-dominated envelopes that initially formed beyond the ice line to water worlds (i.e., with a water-enriched envelope) when the disk gas is depleted by ≳2 orders of magnitude, allowing gentle migration. We additionally discuss the expected C/O ratio profile under pollution by water and refractory carbon species.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"257 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142713311","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}
Pub Date : 2024-11-25DOI: 10.3847/1538-4357/ad7f4b
Li-Heng Wang, Kai Li, Ya-Ni Guo, Jing-Yi Wang, Xiang Gao, Xing Gao and Guo-You Sun
This paper selected eight totally eclipsing contact binaries for photometric and spectroscopic studies. Spectral data were analyzed by University of Lyon Spectroscopic analysis Software, and photometric data were analyzed using PHOEBE through Markov Chain Monte Carlo (MCMC) sampling. We used two methods to calculate the initial values for running MCMC: one method is a new approach proposed by ourselves to model light curves without spots, while the other method is the genetic algorithm, which can determine physical parameters with spots. The results imply that these eight targets are all contact binary stars with a small mass ratio below 0.25. There are four systems exhibiting the O’Connell effect. By adding a dark spot on the primary component, the ideal fitting can be obtained. Meanwhile, it was found that two systems are shallow contact binaries, while the remaining six are moderate contact binaries. An O − C analysis of the eight eclipsing binary stars revealed that seven of them exhibit long-term changes. Four of them display a long-term decreasing trend in orbital period, while the other three show a long-term increasing trend, and two targets exhibit periodic variations. A decrease in period may be caused by the transfer of matter from the more massive component to the less massive component, while an increase in period may be caused by transfer in the opposite way. The absolute physical parameters, orbital angular momentum, initial masses, and ages of these eight systems were calculated. Additionally, their mass–luminosity and mass–radius distributions were analyzed.
本文选取了八颗全食接触双星进行光度和光谱研究。光谱数据由里昂大学光谱分析软件进行分析，光度数据则通过马尔可夫链蒙特卡罗（MCMC）采样法用PHOEBE进行分析。我们使用了两种方法来计算运行 MCMC 的初始值：一种方法是我们自己提出的一种新方法，用于模拟没有光斑的光曲线；另一种方法是遗传算法，它可以确定有光斑的物理参数。结果表明，这八个目标都是质量比小于 0.25 的接触双星。有四个系统表现出了奥康纳尔效应。通过在主成分上添加一个暗斑，可以得到理想的拟合结果。同时，还发现有两个系统是浅接触双星，其余六个是中等接触双星。对八颗食双星的 O - C 分析显示，其中七颗呈现长期变化。其中四颗的轨道周期呈长期下降趋势，另外三颗呈长期上升趋势，还有两个目标呈周期性变化。轨道周期的减小可能是由于物质从质量较大的部分转移到质量较小的部分，而轨道周期的增大则可能是由于相反的转移。我们计算了这八个系统的绝对物理参数、轨道角动量、初始质量和年龄。此外，还分析了它们的质量-光度和质量-半径分布。
{"title":"Photometric and Spectroscopic Analysis of Eight Totally Eclipsing Contact Binaries with Small Mass Ratios","authors":"Li-Heng Wang, Kai Li, Ya-Ni Guo, Jing-Yi Wang, Xiang Gao, Xing Gao and Guo-You Sun","doi":"10.3847/1538-4357/ad7f4b","DOIUrl":"https://doi.org/10.3847/1538-4357/ad7f4b","url":null,"abstract":"This paper selected eight totally eclipsing contact binaries for photometric and spectroscopic studies. Spectral data were analyzed by University of Lyon Spectroscopic analysis Software, and photometric data were analyzed using PHOEBE through Markov Chain Monte Carlo (MCMC) sampling. We used two methods to calculate the initial values for running MCMC: one method is a new approach proposed by ourselves to model light curves without spots, while the other method is the genetic algorithm, which can determine physical parameters with spots. The results imply that these eight targets are all contact binary stars with a small mass ratio below 0.25. There are four systems exhibiting the O’Connell effect. By adding a dark spot on the primary component, the ideal fitting can be obtained. Meanwhile, it was found that two systems are shallow contact binaries, while the remaining six are moderate contact binaries. An O − C analysis of the eight eclipsing binary stars revealed that seven of them exhibit long-term changes. Four of them display a long-term decreasing trend in orbital period, while the other three show a long-term increasing trend, and two targets exhibit periodic variations. A decrease in period may be caused by the transfer of matter from the more massive component to the less massive component, while an increase in period may be caused by transfer in the opposite way. The absolute physical parameters, orbital angular momentum, initial masses, and ages of these eight systems were calculated. Additionally, their mass–luminosity and mass–radius distributions were analyzed.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"119 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697033","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}
Pub Date : 2024-11-25DOI: 10.3847/1538-4357/ad8579
Hadi Madanian, Li-Jen Chen, Jonathan Ng, Michael J. Starkey, Stephen A. Fuselier, Naoki Bessho, Daniel J. Gershman and Terry Z. Liu
The magnetic cloud within an interplanetary coronal mass ejection (ICME) is characterized by high magnetic field intensities. In this study, we investigate the interaction of a magnetic cloud carrying a density structure with the Earth’s bow shock during the ICME event on 2023 April 24. Elevated abundances of cold protons and heavier ions, namely, alpha particles and singly charged helium ions, associated with the prominence plasma are observed within this structure. The plasma downstream of the bow shock exhibits an irregular compression pattern, which could be due to the presence of heavy ions. Heavy ions carry a significant fraction of the upstream flow energy; however, due to their different mass-per-charge ratio and rigidity, they are less scattered by the electromagnetic and electrostatic waves at the shock. We find that downstream of the shock, while the ion thermal energy is only a small fraction of the background magnetic energy, nevertheless increased ion fluxes reduce the characteristic wave speeds in that region. As such, we observe a transition state of an unstable bow shock in which the plasma flow is super Alfvénic both upstream and downstream of the bow shock. Our findings help with the understanding of the intense space weather impacts of such events.
{"title":"Interaction of the Prominence Plasma within the Magnetic Cloud of an Interplanetary Coronal Mass Ejection with the Earth’s Bow Shock","authors":"Hadi Madanian, Li-Jen Chen, Jonathan Ng, Michael J. Starkey, Stephen A. Fuselier, Naoki Bessho, Daniel J. Gershman and Terry Z. Liu","doi":"10.3847/1538-4357/ad8579","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8579","url":null,"abstract":"The magnetic cloud within an interplanetary coronal mass ejection (ICME) is characterized by high magnetic field intensities. In this study, we investigate the interaction of a magnetic cloud carrying a density structure with the Earth’s bow shock during the ICME event on 2023 April 24. Elevated abundances of cold protons and heavier ions, namely, alpha particles and singly charged helium ions, associated with the prominence plasma are observed within this structure. The plasma downstream of the bow shock exhibits an irregular compression pattern, which could be due to the presence of heavy ions. Heavy ions carry a significant fraction of the upstream flow energy; however, due to their different mass-per-charge ratio and rigidity, they are less scattered by the electromagnetic and electrostatic waves at the shock. We find that downstream of the shock, while the ion thermal energy is only a small fraction of the background magnetic energy, nevertheless increased ion fluxes reduce the characteristic wave speeds in that region. As such, we observe a transition state of an unstable bow shock in which the plasma flow is super Alfvénic both upstream and downstream of the bow shock. Our findings help with the understanding of the intense space weather impacts of such events.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697035","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}
Pub Date : 2024-11-25DOI: 10.3847/1538-4357/ad865b
Kai E. Yang, 凯 杨, Lucas A. Tarr, Matthias Rempel, S. Curt Dodds, Sarah A. Jaeggli, Peter Sadowski, Thomas A. Schad, Ian Cunnyngham, Jiayi Liu, 嘉奕 刘, Yannik Glaser, Xudong Sun and 旭东 孙
The National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST) will provide high-resolution, multiline spectropolarimetric observations that are poised to revolutionize our understanding of the Sun. Given the massive data volume, novel inference techniques are required to unlock its full potential. Here, we provide an overview of our “SPIn4D” project, which aims to develop deep convolutional neural networks (CNNs) for estimating the physical properties of the solar photosphere from DKIST spectropolarimetric observations. We describe the magnetohydrodynamic (MHD) modeling and the Stokes profile synthesis pipeline that produce the simulated output and input data, respectively. These data will be used to train a set of CNNs that can rapidly infer the four-dimensional MHD state vectors by exploiting the spatiotemporally coherent patterns in the Stokes profile time series. Specifically, our radiative MHD model simulates the small-scale dynamo actions that are prevalent in quiet-Sun and plage regions. Six cases with different mean magnetic fields have been explored; each case covers six solar-hours, totaling 109 TB in data volume. The simulation domain covers at least 25 × 25 × 8 Mm, with 16 × 16 × 12 km spatial resolution, extending from the upper convection zone up to the temperature minimum region. The outputs are stored at a 40 s cadence. We forward model the Stokes profile of two sets of Fe i lines at 630 and 1565 nm, which will be simultaneously observed by DKIST and can better constrain the parameter variations along the line of sight. The MHD model output and the synthetic Stokes profiles are publicly available, with 13.7 TB in the initial release.
{"title":"Spectropolarimetric Inversion in Four Dimensions with Deep Learning (SPIn4D). I. Overview, Magnetohydrodynamic Modeling, and Stokes Profile Synthesis","authors":"Kai E. Yang, 凯 杨, Lucas A. Tarr, Matthias Rempel, S. Curt Dodds, Sarah A. Jaeggli, Peter Sadowski, Thomas A. Schad, Ian Cunnyngham, Jiayi Liu, 嘉奕 刘, Yannik Glaser, Xudong Sun and 旭东 孙","doi":"10.3847/1538-4357/ad865b","DOIUrl":"https://doi.org/10.3847/1538-4357/ad865b","url":null,"abstract":"The National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST) will provide high-resolution, multiline spectropolarimetric observations that are poised to revolutionize our understanding of the Sun. Given the massive data volume, novel inference techniques are required to unlock its full potential. Here, we provide an overview of our “SPIn4D” project, which aims to develop deep convolutional neural networks (CNNs) for estimating the physical properties of the solar photosphere from DKIST spectropolarimetric observations. We describe the magnetohydrodynamic (MHD) modeling and the Stokes profile synthesis pipeline that produce the simulated output and input data, respectively. These data will be used to train a set of CNNs that can rapidly infer the four-dimensional MHD state vectors by exploiting the spatiotemporally coherent patterns in the Stokes profile time series. Specifically, our radiative MHD model simulates the small-scale dynamo actions that are prevalent in quiet-Sun and plage regions. Six cases with different mean magnetic fields have been explored; each case covers six solar-hours, totaling 109 TB in data volume. The simulation domain covers at least 25 × 25 × 8 Mm, with 16 × 16 × 12 km spatial resolution, extending from the upper convection zone up to the temperature minimum region. The outputs are stored at a 40 s cadence. We forward model the Stokes profile of two sets of Fe i lines at 630 and 1565 nm, which will be simultaneously observed by DKIST and can better constrain the parameter variations along the line of sight. The MHD model output and the synthetic Stokes profiles are publicly available, with 13.7 TB in the initial release.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"140 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697036","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}
Pub Date : 2024-11-25DOI: 10.3847/1538-4357/ad88e9
Andrzej Niedźwiecki, Michał Szanecki and Agnieszka Janiuk
We study spectra produced by weakly accreting black hole (BH) systems using the semianalytic advection-dominated accretion flow (ADAF) model and the general-relativistic magnetohydrodynamic (GRMHD) simulation. We find significant differences between these two approaches related to a wider spread of the flow parameters as well as a much steeper radial distribution of the magnetic field in the latter. We apply these spectral models to the broadband spectral energy distribution (SED) of the nucleus of the M87 galaxy. The standard (in particular, 1D) formulation of the ADAF model does not allow us to explain it; previous claims that this model reproduces the observed SED suffer from an inaccurate treatment of the Compton process. The spectra based on GRMHD simulation are in a much better agreement with the observed data. In our GRMHD model, in which we assumed the BH spin a = 0.9, the bulk of radiation observed between the millimeter and the X-ray range is produced in the disk area within 4 gravitational radii from the BH. In this solution, the synchrotron component easily reproduces the spectral data between the millimeter and the UV range, and the Compton component does not violate the X-rays constraints, for yr−1 and a relatively strong magnetic field, with the plasma β ∼ 1 in the region where radiation is produced. However, the Compton component cannot explain the observed X-ray spectrum. Instead, the X-ray spectrum can be reproduced by a high-energy tail of the synchrotron spectrum if electrons have a hybrid energy distribution with a ∼5% nonthermal component.
我们利用半解析吸积流（ADAF）模型和广义相对论磁流体动力学（GRMHD）模拟，研究了弱吸积黑洞（BH）系统产生的光谱。我们发现这两种方法存在明显差异，前者的流动参数分布更广，后者的磁场径向分布更陡峭。我们将这些光谱模型应用于 M87 星系核的宽带光谱能量分布（SED）。ADAF模型的标准（特别是一维）表述并不能让我们解释它；以前声称该模型可以再现观测到的SED，是因为对康普顿过程的处理不准确。基于 GRMHD 模拟的光谱与观测数据的一致性要好得多。在我们的 GRMHD 模型中，我们假定 BH 自旋 a = 0.9，在毫米和 X 射线范围内观测到的大部分辐射都产生于距离 BH 4 个引力半径范围内的盘区。在这个方案中，同步辐射成分很容易再现毫米波和紫外波段之间的光谱数据，而康普顿成分也没有违反 X 射线约束条件，即在年-1 和相对较强的磁场条件下，辐射产生区域的等离子体 β ∼ 1。然而，康普顿成分无法解释观测到的 X 射线光谱。相反，如果电子具有混合能量分布，其中有 ∼5% 的非热量成分，那么同步辐射光谱的高能量尾部就可以再现 X 射线光谱。
{"title":"Broadband Spectral Modeling of the M87 Nucleus","authors":"Andrzej Niedźwiecki, Michał Szanecki and Agnieszka Janiuk","doi":"10.3847/1538-4357/ad88e9","DOIUrl":"https://doi.org/10.3847/1538-4357/ad88e9","url":null,"abstract":"We study spectra produced by weakly accreting black hole (BH) systems using the semianalytic advection-dominated accretion flow (ADAF) model and the general-relativistic magnetohydrodynamic (GRMHD) simulation. We find significant differences between these two approaches related to a wider spread of the flow parameters as well as a much steeper radial distribution of the magnetic field in the latter. We apply these spectral models to the broadband spectral energy distribution (SED) of the nucleus of the M87 galaxy. The standard (in particular, 1D) formulation of the ADAF model does not allow us to explain it; previous claims that this model reproduces the observed SED suffer from an inaccurate treatment of the Compton process. The spectra based on GRMHD simulation are in a much better agreement with the observed data. In our GRMHD model, in which we assumed the BH spin a = 0.9, the bulk of radiation observed between the millimeter and the X-ray range is produced in the disk area within 4 gravitational radii from the BH. In this solution, the synchrotron component easily reproduces the spectral data between the millimeter and the UV range, and the Compton component does not violate the X-rays constraints, for yr−1 and a relatively strong magnetic field, with the plasma β ∼ 1 in the region where radiation is produced. However, the Compton component cannot explain the observed X-ray spectrum. Instead, the X-ray spectrum can be reproduced by a high-energy tail of the synchrotron spectrum if electrons have a hybrid energy distribution with a ∼5% nonthermal component.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"281 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697043","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}
Pub Date : 2024-11-25DOI: 10.3847/1538-4357/ad8cd9
Gexing Li and Zhihong Li
The determination of neutrino mass hierarchy is crucial for particle physics, astrophysics, and cosmology. In this work, we propose an easy-to-use method to determine the neutrino hierarchy based on core-collapse supernova (CCSN) neutrino detections. By analyzing the expected event rates of the neutrino burst at a terrestrial water Cherenkov detector, we found that the event rates predicted by the normal and inverted hierarchy models have marked differences in the neutrino energy range 10 ∼ 20 MeV and the postbounce time <0.5 s. Within this specific energy and time range, the analytical relationship between the cumulative event number and proto–neutron star (PNS) baryon mass is extracted. Based on the normal and inverted hierarchy models, two different PNS masses can be inferred from this relationship by using the time profile of neutrino events. Then, the neutrino hierarchy can be determined by comparing the PNS mass inferred from the neutrino detections and the electromagnetic or gravitational-wave channels. Furthermore, the nonadiabatic part of the Mikheyev–Smirnov–Wolfenstein flavor conversions may also be quantified with this method, which would be very helpful for the studies of the explosion mechanism and nucleosynthesis of CCSNe.
{"title":"A Promising Approach for Determining Neutrino Mass Hierarchy by Using Supernova Neutrino Detections","authors":"Gexing Li and Zhihong Li","doi":"10.3847/1538-4357/ad8cd9","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8cd9","url":null,"abstract":"The determination of neutrino mass hierarchy is crucial for particle physics, astrophysics, and cosmology. In this work, we propose an easy-to-use method to determine the neutrino hierarchy based on core-collapse supernova (CCSN) neutrino detections. By analyzing the expected event rates of the neutrino burst at a terrestrial water Cherenkov detector, we found that the event rates predicted by the normal and inverted hierarchy models have marked differences in the neutrino energy range 10 ∼ 20 MeV and the postbounce time <0.5 s. Within this specific energy and time range, the analytical relationship between the cumulative event number and proto–neutron star (PNS) baryon mass is extracted. Based on the normal and inverted hierarchy models, two different PNS masses can be inferred from this relationship by using the time profile of neutrino events. Then, the neutrino hierarchy can be determined by comparing the PNS mass inferred from the neutrino detections and the electromagnetic or gravitational-wave channels. Furthermore, the nonadiabatic part of the Mikheyev–Smirnov–Wolfenstein flavor conversions may also be quantified with this method, which would be very helpful for the studies of the explosion mechanism and nucleosynthesis of CCSNe.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"189 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697107","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}
Pub Date : 2024-11-25DOI: 10.3847/1538-4357/ad8881
Emre Işık, Sami K. Solanki, Robert H. Cameron and Alexander I. Shapiro
Besides a dense coverage of their high latitudes by starspots, rapidly rotating cool stars also display low-latitude spots in Doppler images, although generally with lower coverage. In contrast, flux emergence models of fast-rotating stars predict strong poleward deflection of radially rising magnetic flux as the Coriolis effect dominates over buoyancy, leaving a spot-free band around the equator. To resolve this discrepancy, we consider a flux tube near the base of the convection zone in a solar-type star rotating 8 times faster than the Sun, assuming field intensification by weak-tube explosions. For the intensification to continue into the buoyancy-dominated regime, the upper convection zone must have a significantly steeper temperature gradient than in the Sun by a factor that is comparable with that found in 3D simulations of rotating convection. Within the hypothesis that stellar active regions stem from the base of the convection zone, flux emergence between the equator and 20° latitudes requires highly supercritical field strengths of up to 500 kG in rapidly rotating stars. These field strengths require explosions of 100 kG tubes within the convection zone, compatible with reasonable values of the superadiabatic temperature gradient associated with the more rapid rotation.
除了星斑密集覆盖高纬度地区外，快速旋转的冷星也会在多普勒图像中显示低纬度地区的星斑，不过覆盖率一般较低。与此相反，快速旋转恒星的磁通量涌现模型预测，由于科里奥利效应超过了浮力，径向上升的磁通量会发生强烈的极向偏转，从而在赤道周围留下一个无星斑带。为了解决这一差异，我们考虑了太阳型恒星对流区底部附近的磁通量管，其旋转速度是太阳的 8 倍，假定磁场通过弱管爆炸而增强。要使强化持续到浮力主导机制，上部对流区的温度梯度必须比太阳陡峭得多，其系数与旋转对流三维模拟中发现的系数相当。根据恒星活动区源自对流区底部的假设，在赤道和 20° 纬度之间出现的通量需要快速旋转恒星中高达 500 kG 的高度超临界场强。这些场强要求对流区内有 100 kG 的爆炸管，这与与更快速旋转相关的超绝热温度梯度的合理值相一致。
{"title":"Low-latitude Magnetic Flux Emergence on Rapidly Rotating Solar-type Stars","authors":"Emre Işık, Sami K. Solanki, Robert H. Cameron and Alexander I. Shapiro","doi":"10.3847/1538-4357/ad8881","DOIUrl":"https://doi.org/10.3847/1538-4357/ad8881","url":null,"abstract":"Besides a dense coverage of their high latitudes by starspots, rapidly rotating cool stars also display low-latitude spots in Doppler images, although generally with lower coverage. In contrast, flux emergence models of fast-rotating stars predict strong poleward deflection of radially rising magnetic flux as the Coriolis effect dominates over buoyancy, leaving a spot-free band around the equator. To resolve this discrepancy, we consider a flux tube near the base of the convection zone in a solar-type star rotating 8 times faster than the Sun, assuming field intensification by weak-tube explosions. For the intensification to continue into the buoyancy-dominated regime, the upper convection zone must have a significantly steeper temperature gradient than in the Sun by a factor that is comparable with that found in 3D simulations of rotating convection. Within the hypothesis that stellar active regions stem from the base of the convection zone, flux emergence between the equator and 20° latitudes requires highly supercritical field strengths of up to 500 kG in rapidly rotating stars. These field strengths require explosions of 100 kG tubes within the convection zone, compatible with reasonable values of the superadiabatic temperature gradient associated with the more rapid rotation.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697042","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}
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