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Related papers: Modeling $\epsilon$ Eridani and asteroseismic test…

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We estimate the main-sequence age and heavy-element abundance of the Sun by means of an asteroseismic calibration of theoretical solar models using only low-degree acoustic modes from the BiSON. The method can therefore be applied also to…

Solar and Stellar Astrophysics · Physics 2015-05-30 G. Houdek , D. O. Gough

Despite the fact that the initial helium abundance is an essential ingredient in modelling solar-type stars, its abundance in these stars remains a poorly constrained observational property. This is because the effective temperature in…

Solar and Stellar Astrophysics · Physics 2021-01-20 Nuno Moedas , Benard Nsamba , Miguel T. Clara

Diffusion of elements in the atmosphere and envelope of a star can drastically alter its surface composition, leading to extreme chemical peculiarities. We consider the case of hot subdwarfs, where surface helium abundances range from…

Solar and Stellar Astrophysics · Physics 2018-02-02 Conor M. Byrne , C. Simon Jeffery , Christopher A. Tout , Haili Hu

We include gaseous continuum and line emission into our GALEV models for the spectral and photometric evolution of Simple Stellar Populations (SSPs) for various metallicities in the range 0.02 <= Z/Zsun <= 2.5. This allows to extend them to…

Astrophysics · Physics 2010-04-06 Peter Anders , Uta Fritze -- v. Alvensleben

A study of the IGM metal enrichment using a series of SPH simulations is presented, employing metal cooling and turbulent diffusion of metals and thermal energy. An adiabatic feedback mechanism was adopted where gas cooling was prevented to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Sijing Shen , James Wadsley , Gregory Stinson

We study the structural characteristic of the variable DA white dwarf G117B-15A by applying the methods of asteroseismology. For such a purpose, we construct white dwarf evolutionary models considering a detailed and up-to-date physical…

Astrophysics · Physics 2009-11-07 O. G. Benvenuto , A. H. Corsico , L. G. Althaus , A. M. Serenelli

When modelling stars with masses larger than 1.2Msun with no observed chemical peculiarity, atomic diffusion is often neglected because, on its own, it causes unrealistic surface abundances compared with those observed. The reality is that…

Solar and Stellar Astrophysics · Physics 2019-12-25 M. Deal , M-J. Goupil , J. P. Marques , D. Reese , Y. Lebreton

The characterization of the growing number of newly discovered exoplanets ---nature, internal structure, formation and evolution--- strongly relies on the properties of their host-star, i.e. its mass, radius and age. These latter can be…

Solar and Stellar Astrophysics · Physics 2011-09-01 Yveline Lebreton

The distributions of a galaxy's gas and stars in chemical space encodes a tremendous amount of information about that galaxy's physical properties and assembly history. However, present methods for extracting information from chemical…

Astrophysics of Galaxies · Physics 2018-02-14 Mark R. Krumholz , Yuan-Sen Ting

We revisit the problem of low-mass pre-main-sequence (PMS) stellar evolution and its observational consequences for where stars fall on the Hertzsprung-Russell diagram (HRD). In contrast to most previous work, our models follow stars as…

Solar and Stellar Astrophysics · Physics 2015-05-27 Takashi Hosokawa , Stella S. R. Offner , Mark R. Krumholz

We present an updated release of the BaSTI (a Bag of Stellar Tracks and Isochrones) stellar model and isochrone library for a solar scaled heavy element distribution. The main input physics changed from the previous BaSTI release include…

Astrophysics of Galaxies · Physics 2018-04-11 S. L. Hidalgo , A. Pietrinferni , S. Cassisi , M. Salaris , A. Mucciarelli , A. Savino , A. Aparicio , V. Silva Aguirre , K. Verma

Diffusion of atoms can be important during quiescent phases of stellar evolution. Particularly in the very thin inert envelopes of subdwarf B stars, diffusive movements will considerably change the envelope structure and the surface…

Solar and Stellar Astrophysics · Physics 2015-05-14 Haili Hu , E. Glebbeek , A. A. Thoul , M. -A. Dupret , R. J. Stancliffe , G. Nelemans , C. Aerts

We build, as far as theory will permit, self consistent model HII regions around central clusters of aging stars. These produce strong emission line diagnostics applicable to either individual HII regions in galaxies, or to the integrated…

Stellar evolution calculations were carried out from the main sequence to the final AGB stage of stars with initial masses from 1 to $2M_\odot$ and metallicity $Z=0.01$. Selected models of evolutionary sequences were used as initial…

Solar and Stellar Astrophysics · Physics 2018-09-11 Yuri Fadeyev

The physical parameters of the retired A star HD 185351 were analysed in great detail by Johnson et al. (2014) using interferometry, spectroscopy and asteroseismology. Results from all independent methods are consistent with HD 185351…

Recent dramatic improvements in the modeling of abundance evolution due to diffusion in A stars have been achieved with the help of monochromatic opacity tables from the OPAL group. An important result in the context of stellar pulsations…

Astrophysics · Physics 2007-05-23 S. Turcotte , J. Richer , G. Michaud , J. Christensen-Dalsgaard

We present analyses of observations of epsilon Eridani (K2 V) made with the Low Energy Transmission Grating Spectrometer on Chandra and the Extreme Ultraviolet Explorer, supplemented by observations made with the Space Telescope Imaging…

Astrophysics · Physics 2009-11-13 J. -U. Ness , C. Jordan

Coronal mass ejections (CMEs) are a prominent contributor to solar system space weather and might have impacted the Sun's early angular momentum evolution. A signal diagnostic of CMEs on the Sun is coronal dimming: a drop in coronal…

Stellar models with masses ranging from 0.5 to $1.3~M_\odot$ were constructed in order to compare to young cluster observations of Li and of rotation velocities. The amount of Li depletion in cool stars is sensitive to the amount of…

Astrophysics · Physics 2009-10-22 Brian Chaboyer , P. Demarque , M. H. Pinsonneault

We present detailed evolutionary calculations focused on the evolution of intermediate mass stars with 3 Msun < M < 9 Msun of metallicity typical of the Large Magellanic Cloud (LMC), i.e. Z=0.008. We compare carefully the models calculated…

Astrophysics · Physics 2009-11-11 P. Ventura , M. Castellani , C. W. Straka