由冷演化恒星的大气层产生的分子和尘埃贡献了星际介质中发现的大量物质。为了了解这些恒星质量损失背后的机制，研究其大气层的结构和动力学至关重要。我们的目标是验证富碳渐近巨星分支（AGB）恒星V Oph的扩展分子和尘埃层及其时间变化是否可以由恒星脉动单独触发的尘埃驱动风来解释，或者是否有其他机制在起作用。我们使用最新一代的富碳恒星自洽动力学大气模型DARWIN，模拟了V Oph中红外干涉VLTI-VLT数据（$8$ - $13~μ$ m），在相位$0.18$，$0.49$，$0.65$，以及文献测光数据。我们确定了恒星的基本参数：$T_\text{eff} = 2600~$ K，$L_\text{bol} = 3585~$ L $_{\odot}$，$M = 1.5~$ M $_{\odot}$，$C/O = 1.35$，$\dot{M} = 2.50\cdot10^{-6}$ M $_{\odot}$ /yr。本文计算了三个位相的恒星光球半径：$479$，$494$，$448$ R $_{\odot}$和尘埃半径：$780$，$853$，$787$ R $_{\odot}$。动力学模型能较好地解释观测到的$N$波段的可见度和光谱，但与实验数据存在一定的差异，本文对此进行了讨论。我们讨论了可能的原因的时间变化的外大气，推导出的磁场强度的估计，并计算上限的阿尔文波的速度。此外，使用周期光度序列和干涉建模，我们建议V Oph作为候选人被重新分类为半正规星。
英文摘要：
Molecules and dust produced by the atmospheres of cool evolved stars contribute to a significant amount of the total material found in the interstellar medium. To understand the mechanism behind the mass loss of these stars, it is of pivotal importance to investigate the structure and dynamics of their atmospheres.
Our goal is to verify if the extended molecular and dust layers of the carbon-rich asymptotic giant branch (AGB) star V Oph, and their time variations, can be explained by dust-driven winds triggered by stellar pulsation alone, or if other mechanisms are operating.
We model V Oph mid-infrared interferometric VLTI-MIDI data ($8$-$13~μ$m), at phases $0.18$, $0.49$, $0.65$, together with literature photometric data, using the latest-generation self-consistent dynamic atmosphere models for carbon-rich stars: DARWIN.
We determine the fundamental stellar parameters: $T_\text{eff} = 2600~$K, $L_\text{bol} = 3585~$L$_{\odot}$, $M = 1.5~$M$_{\odot}$, $C/O = 1.35$, $\dot{M} = 2.50\cdot10^{-6}$M$_{\odot}$/yr. We calculate the stellar photospheric radii at the three phases: $479$, $494$, $448$ R$_{\odot}$; and the dust radii: $780$, $853$, $787$ R$_{\odot}$. The dynamic models can fairly explain the observed $N$-band visibility and spectra, although there is some discrepancy between the data and the models, which is discussed in the text.
We discuss the possible causes of the temporal variations of the outer atmosphere, deriving an estimate of the magnetic field strength, and computing upper limits for the Alfvén waves velocity. In addition, using period-luminosity sequences, and interferometric modeling, we suggest V Oph as a candidate to be reclassified as a semi-regular star.
Evolution of Thermally Pulsing Asymptotic Giant Branch Stars V: Constraining the Mass Loss and Lifetimes of Intermediate Mass, Low Metallicity AGB Stars
VLA cm-wave survey of young stellar objects in the Oph A cluster: constraining extreme UV- and X-ray-driven disk photo-evaporation -- A pathfinder for Square Kilometre Array studies
Constraining the thermally-pulsing asymptotic giant branch phase with resolved stellar populations in the Small Magellanic Cloud
中低质量恒星经历的热脉冲渐近巨星分支（TP-AGB）是恒星演化中最不确定的阶段之一，模型需要借助观测进行校正。为此，我们耦合高质量的观测解析恒星在小麦哲伦云（SMC）与详细的恒星星族合成模拟计算的TRILEGAL代码。我们的方法的强度依赖于详细的空间分辨的恒星形成历史的SMC，来自深近红外测光的VISTA调查的麦哲伦云，以及快速，准确地探索各种各样的参数和影响的能力与COLIBRI代码的TP-AGB的演变。采用一组特征良好的观测结果-恒星计数和光度函数-我们建立了一个校准周期，沿着这个周期，我们迭代地改变TP-AGB模型的一些关键参数，直到我们最终达到与观测结果的良好拟合。我们的工作导致确定两个最佳拟合模型，主要是不同的效率的第三次疏浚和质量损失的TP-AGB星的初始质量大于约3 M $_{\odot}$。在这些校准模型的基础上，我们提供了一个完整的表征TP-AGB恒星星族在SMC的恒星参数（初始质量，C/O比，碳过剩，质量损失率）。包括这些改进模型在内的广泛的等时线表是公开可用的。
Large-scale variability in macroturbulence driven by pulsations in the rapidly rotating massive star Zeta Oph from high-cadence ESPRESSO spectroscopy and TESS photometry
Newcastle University（纽卡斯尔大学）；KU Leuven（荷语鲁汶大学）；Universidad de La Laguna（拉古纳大学）
An empirical view of the extended atmosphere and inner envelope of the asymptotic giant branch star R Doradus. II. Constraining the dust properties with radiative transfer modelling
Chalmers University of Technology（查尔姆斯理工大学）；Gothenburg University（哥德堡大学）
Thermohaline instability and rotation-induced mixing. III - Grid of stellar models and asymptotic asteroseismic quantities from the pre-main sequence up to the AGB for low- and intermediate-mass stars at various metallicities
Chemical Signatures of AGB Mass Transfer in Gaia White Dwarf Companions
California Institute of Technology（加州理工学院）；Gemini Observatory, NSF’s NOIRLab（双子座天文台，美国国家光学-红外天文研究实验室）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）
The impact of surface acetylene cyclotrimerization on the abundance of aromatic hydrocarbons in carbon-rich asymptotic giant branch stars
Institute of Astronomy of Russian Academy of Sciences（俄罗斯科学院天文学研究所）；Lomonosov Moscow State University（莫斯科国立罗蒙诺索夫大学）；Skolkovo Institute of Science and Technology（斯科尔科沃科学技术学院）；Samara Branch of P. N. Lebedev Physical Institute of the Russian Academy of Sciences（俄罗斯科学院列别杰夫物理研究所萨马拉分部）；Ural Federal University（乌拉尔联邦大学）
