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Related papers: The lithium-rotation correlation for WTTS in Tauru…

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Neutrino losses play a crucial role in the evolution of massive stars. We study the neutrino luminosity of stars ranging from 20 to 90 M_{\odot} from Zero Age Main Sequence (ZAMS) to Fe Core Collapse (FeCC) with different rotation and…

Solar and Stellar Astrophysics · Physics 2023-10-17 Hao Wang , Chunhua Zhu , Helei Liu , Sufen Guo , Guoliang Lü

Two problems are discussed here. The first one is the 0.4 dex discrepancy between the 7Li abundance derived from the spectra of metal-poor halo stars on the one hand, and from Big Bang nucleosynthesis, based on the cosmological parameters…

Rotation is one of the key stellar parameters which undergo substantial evolution during the stellar lifetime, in particular during the early stages. Stellar rotational periods can be determined on the basis of the periodic modulation of…

Solar and Stellar Astrophysics · Physics 2015-06-12 Laura Affer , Giuseppina Micela , Fabio Favata , Ettore Flaccomio , Jerome Bouvier

We report discovery of significant depletion of Li on the surfaces of F dwarf stars in the 150-Myr-old open cluster M35, analagous to a feature in the 700-Myr-old Hyades cluster that has been referred to as the ``Li gap.'' We have caught…

Astrophysics · Physics 2009-11-10 Aaron Steinhauer , Constantine P. Deliyannis

In Paper I, we classified a stellar sample from the thin disc with a broad range in metallicity as being churned outward or inward, or blurred/undisturbed. In this paper (Paper II), we delve deeper by analysing our entire…

Solar and Stellar Astrophysics · Physics 2025-07-11 M. L. L. Dantas , R. Smiljanic , D. Romano , G. Guiglion , L. Magrini , P. B. Tissera , R. S. de Souza

We report on the abundance analysis of Li in solar-type (G-type main sequence) superflare stars which were found by the analysis of Kepler photometric data. Li is a key element to understand the evolution of the stellar convection zone…

Solar and Stellar Astrophysics · Physics 2015-07-15 Satoshi Honda , Yuta Notsu , Hiroyuki Maehara , Shota Notsu , Takuya Shibayama , Daisaku Nogami , Kazunari Shibata

We construct models for the rotation rates of T Tauri stars whose spin is regulated by magnetic linkage between the star and a surrounding accretion disc. Our models utilise a time-dependent disc code to follow the accretion process and…

Astrophysics · Physics 2015-06-24 P. J. Armitage , C. J. Clarke

We present the results of a spectroscopic survey of X-ray selected, low-mass candidate members of the young open cluster NGC 2547. Using a combination of photometry, spectroscopic indices and radial velocities we refine our candidate list…

Astrophysics · Physics 2009-11-07 R. D Jeffries , J. M. Oliveira , D. Barrado y Navascues , J. R. Stauffer

We have obtained high-dispersion spectra for 256 pre-main-sequence stars in the Orion Nebula Cluster in order to measure their projected rotational velocities and study the rotational evolution and physical properties of young, low-mass…

Astrophysics · Physics 2009-11-07 K. L. Rhode , W. Herbst , R. D. Mathieu

We exploit the unique characteristics of a sample of open clusters (OCs) and field stars for which high-precision 7Li abundances and stellar parameters are homogeneously derived by the Gaia-ESO Survey (GES). We derive possibly undepleted…

Rotation deeply affects the evolution of very metal poor massive stars. Indeed, even moderately rotating stars reach the break--up limit during the Main--Sequence (MS) phase, they evolve rapidly to the red after the core H--burning phase…

Astrophysics · Physics 2007-05-23 Georges Meynet , André Maeder , Sylvia Ekström

Current observations indicate that stars with higher rotation rates appear to maintain more surface lithium, and the majority of lithium-rich giants are indeed red clump stars. Hence, we investigate the mechanisms behind lithium enrichment…

Solar and Stellar Astrophysics · Physics 2025-02-21 Xue-Feng Li , Jian-Rong Shi , Yan Li , Hong-Liang Yan , Jing-Hua Zhang

We conducted a 12-month monitoring campaign of 33 T Tauri stars (TTS) in Taurus. Our goal was to monitor objects that possess a disk but have a weak Halpha line, a common accretion tracer for young stars, to determine whether they host a…

Solar and Stellar Astrophysics · Physics 2017-10-11 Gaspard Duchene , Adam Becker , Yizhe Yang , Herve Bouy , Robert J. De Rosa , Jennifer Patience , Julien H. Girard

The connection rotation-CaII emission flux-lithium abundance is analyzed for a sample of bona fide subgiant stars, with evolutionary status determined from HIPPARCOS trigonometric parallax measurements and from the Toulouse-Geneva code.

We show by detailed model computation how much the Pre-Main Sequence (PMS) Lithium depletion depends on the treatment of over-adiabaticity, by taking advantage of the results of new models by Montalb\'an et al., which apply different…

Astrophysics · Physics 2009-11-10 F. D'Antona , J. Montalban

Stellar rotation is a complex function of mass, metallicity, and age and can be altered by binarity. To understand the importance of these parameters in main sequence stars, we have assembled a sample of observations that spans a range of…

The full disk, full of gas and dust, determines the upper limit of planet masses, and its lifetime is critical for planet formation, especially for giant planets. In this work, we studied the evolutionary timescales of the full disks of T…

Solar and Stellar Astrophysics · Physics 2023-12-25 Hasitieer Haerken , Guang-Wei Li , Min Li , Fuqing Duan , Yongheng Zhao

We compare evolutionary models for protoplanetary discs that include disc winds with observational determinations of the disc lifetime and accretion rate in Taurus. Using updated estimates for stellar ages in Taurus, together with published…

Astrophysics · Physics 2009-11-07 Philip J. Armitage , Cathie J. Clarke , Francesco Palla

The lithium-dip observed in mid-F dwarfs remains a long-standing challenge for stellar evolution models. We present high-precision stellar parameters and A(Li) for 22 new comoving pairs, primarily located on the hotter side of the Li-Dip.…

Solar and Stellar Astrophysics · Physics 2025-08-14 Qinghui Sun , Yuan-Sen Ting , Barbara J. Anthony-Twarog , Bruce A. Twarog , Fan Liu , Yuxi , Lu

We present self-consistent calculations coupling numerical hydrodynamics simulations of collapsing pre-stellar cores and stellar evolution models of accreting objects. We analyse the main impact of consistent accretion history on the…

Solar and Stellar Astrophysics · Physics 2016-12-21 I. Baraffe , V. G. Elbakyan , E. I. Vorobyov , G. Chabrier