Seismic diagnostics of solar-like oscillating stars

Li, Yaguang; Du, Minghao; Xie, Binbin; Tian, Zhijia; Bi, Shaolan; Li, Tan-Da; Wu, Yaqian; Liu, Kang

doi:10.1088/1674-4527/17/5/44

Cited by 6 publications

(2 citation statements)

References 60 publications

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“…Yu et al (2018) characterized solarlike oscillations and granulation for 16 094 oscillating red giants by using the long-cadence data of Kepler, which are helpful to lift degeneracies in deriving atmospheric parameters from LAMOST. Li et al (2017) performed asteroseismic analysis on six solar-type stars observed by Kepler with the LK project atmospheric parameters serving as constraints on stellar models. Li et al (2018) conducted an analysis for the asteroseismic binary system KIC 7107778 with a non-eclipsing unresolved companion having solar-like oscillations.…”

Section: Stellar Pulsations and Asteroseismologymentioning

confidence: 99%

Overview of the LAMOST-Kepler project

Cat

Zong

et al. 2020

Res. Astron. Astrophys.

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The NASA Kepler mission obtained long-term high-quality photometric observations for a large number of stars in its original field of view from 2009 to 2013. To provide reliable stellar parameters in a homogeneous way, the LAMOST telescope began to carry out low-resolution spectroscopic observations for as many stars as possible in the Kepler field in 2012. By June 2018, 238 386 low-resolution spectra with SNR g ≥ 6 had been collected for 155 623 stars in the Kepler field, enabling the determination of atmospheric parameters and radial velocities, as well as spectral classification of the target stars. This information has been used by astronomers to carry out research in various fields, including stellar pulsations and asteroseismology, exoplanets, stellar magnetic activity and flares, peculiar stars and the Milky Way, binary stars, etc. We summarize the research progress in these fields where the usage of data from the LAMOST-Kepler (LK) project has played a role. In addition, time-domain medium-resolution spectroscopic observations have been carried out for about 12 000 stars in four central plates of the Kepler field since 2018. The currently available results show that the LAMOST-Kepler medium resolution (LK-MRS) observations provide qualified data suitable for research in additional science projects including binaries, high-amplitude pulsating stars, etc. As LAMOST is continuing to collect both low- and medium-resolution spectra of stars in the Kepler field, we expect more data to be released continuously and new scientific results to appear based on the LK project data.

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Section: Stellar Pulsations and Asteroseismologymentioning

confidence: 99%

Overview of the LAMOST-Kepler project

Cat

Zong

et al. 2020

Res. Astron. Astrophys.

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“…• Recent studies of KIC 6766513 and KIC 10147635 (Li et al 2017) using the YREC included element diffusion of helium and heavy elements but not convective overshooting.…”

Section: Comparison With Previous Studiesmentioning

confidence: 99%

Asteroseismology of 36 Kepler subgiants -- II: Determining ages from detailed modelling

Li,

Bedding,

Christensen-Dalsgaard

et al. 2020

Preprint

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Detailed modelling of stellar oscillations is able to give precise estimates for stellar ages, but the inferred results typically depend on the adopted model parameters used for the age inference. High-quality asteroseismic data with precise measurements of mixed modes are available for 36 Kepler subgiants. To obtain a handle on the robustness of the ages for these stars, we first study the dependencies of seismic ages on three model input parameters. We find that inferred ages do not change systematically with the helium fraction (Y ) or the mixing-length parameter (α MLT ) but depend strongly on the metallicity ([M/H]) of the model. The results indicate that age estimates of subgiants have less model dependence and hence are more reliable than those of main-sequence stars or red giants. We then model individual oscillation frequencies of the same 36 Kepler subgiants, using observed metallicities, and obtain their ages with an average precision of ∼ 15%. The comparison with previous age estimates with different stellar codes or input physics show good agreement (mostly within 2σ). We hence suggest that seismology-determined ages of subgiants are not greatly model-dependent.

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Investigation of the orientation of galaxies in clusters: the importance, methods and results of research

Pajowska¹,

Godlowski²,

Zhu

et al. 2019

J. Cosmol. Astropart. Phys.

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Various models of structure formation can account for various aspects of the galaxy formation process on different scales, as well as for various observational features of structures. Thus, the investigation of galaxies orientation constitute a standard test of galaxies formation scenarios since observed variations in angular momentum represent fundamental constraints for any model of galaxy formation.We have improved the method of analysis of the alignment of galaxies in clusters. Now, the method allows to analyze both position angles of galaxy major axes and two angles describing the spatial orientation of galaxies. The distributions of analyzed angles were tested for isotropy by applying different statistical tests.For sample of analyzed clusters we have computed the mean values of analyzed statistics, checking whether they are the same as expected ones in the case of random distribution of analyzed angles. The detailed discussion of this method has been performed. We have shown how to proceed in many particular cases in order to improve the statistical reasoning when analyzing the distribution of the angles in the observational data. Separately, we have compared these new results with those obtained from numerical simulations. We show how powerful is our method on the example of galaxy orientation analysis in 247 Abell rich galaxy clusters. We have found that the orientations of galaxies in analyzed clusters are not random. It means that we genuinely confirmed an existence of the alignment of galaxies in rich Abells' galaxy clusters. This result is independent from the clusters of Bautz-Morgan types.

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Seismic diagnostics of solar-like oscillating stars

Cited by 6 publications

References 60 publications

Overview of the LAMOST-Kepler project

Overview of the LAMOST-Kepler project

Asteroseismology of 36 Kepler subgiants -- II: Determining ages from detailed modelling

Investigation of the orientation of galaxies in clusters: the importance, methods and results of research

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