Rotation and lithium abundance of solar-analog stars

Nascimento, J. D. do; Costa, J. S. da; Medeiros, J. R. De

doi:10.1051/0004-6361/200811026

Cited by 15 publications

(24 citation statements)

References 32 publications

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“…It is important to emphasize, as shown by the comparison of the models presented here with previous studies, that the amount of internal differential rotation predicted by these models is quite sensitive to the adopted braking law. Robust inferences regarding the history of lithium depletion in solar-type stars would benefit from a more physical modeling of the processes involved (e.g., Charbonnel & Talon 2005;Baraffe & Chabrier 2010;Do Nascimento et al 2010;Eggenberger et al 2010Eggenberger et al , 2012.…”

Section: Wind Braking and Lithium Depletionmentioning

confidence: 99%

Improved angular momentum evolution model for solar-like stars

Gallet

Bouvier

2013

A&A

347

482

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Context. Understanding the origin and evolution of stellar angular momentum is one of the major challenges of stellar physics. Aims. We present new models for the rotational evolution of solar-like stars between 1 Myr and 10 Gyr with the aim of reproducing the distributions of rotational periods observed for star forming regions and young open clusters within this age range. Methods. The models include a new wind braking law based on recent numerical simulations of magnetized stellar winds and specific dynamo and mass-loss prescriptions are adopted to tie angular momentum loss to angular velocity. The models additionally assume constant angular velocity during the disk accretion phase and allow for decoupling between the radiative core and the convective envelope as soon as the former develops. Results. We have developed rotational evolution models for slow, median, and fast rotators with initial periods of 10, 7, and 1.4 d, respectively. The models reproduce reasonably well the rotational behavior of solar-type stars between 1 Myr and 4.5 Gyr, including pre-main sequence (PMS) to zero-age main sequence (ZAMS) spin up, prompt ZAMS spin down, and the early-main sequence (MS) convergence of surface rotation rates. We find the model parameters accounting for the slow and median rotators are very similar to each other, with a disk lifetime of 5 Myr and a core-envelope coupling timescale of 28−30 Myr. In contrast, fast rotators have both shorter disk lifetimes (2.5 Myr) and core-envelope coupling timescales (12 Myr). We show that a large amount of angular momentum is hidden in the radiative core for as long as 1 Gyr in these models and we discuss the implications for internal differential rotation and lithium depletion. We emphasize that these results are highly dependent on the adopted braking law. We also report a tentative correlation between the initial rotational period and disk lifetime, which suggests that protostellar spin down by massive disks in the embedded phase is at the origin of the initial dispersion of rotation rates in young stars. Conclusions. We conclude that this class of semi-empirical models successfully grasp the main trends of the rotational behavior of solar-type stars as they evolve and make specific predictions that may serve as a guide for further development.

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Section: Wind Braking and Lithium Depletionmentioning

confidence: 99%

Improved angular momentum evolution model for solar-like stars

Gallet

Bouvier

2013

A&A

347

482

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“…However, do Nascimento, da Costa & De Medeiros (2010) point out that there is a large range in lithium depletion for solar-type stars which may reflect different rotational histories or be a result of different mixing mechanisms such as shear mixing caused by differential rotation (Bouvier 2008). In analysing the spectra, the equivalent width EW Li was measured using the SPLOT task in IRAF.…”

Section: Lithium-i 67078 Nm: An Age Indicatormentioning

confidence: 99%

High-resolution Spectroscopy and Spectropolarimetry of Some Late F- / Early G-type Sun-like Stars as Targets for Zeeman Doppler Imaging

Waite

Marsden

Carter

et al. 2011

Publ. – Astron. Soc. Aust

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High-resolution spectroscopy and spectropolarimetry have been undertaken at the AngloAustralian Telescope in order to identify suitable targets for magnetic studies of young Sun-like stars, for the proxy study of early solar evolution. This study involved the investigation of some variable late F-/ early G-type Sun-like stars originally identified by the Hipparcos mission. Of the 38 stars observed for this study, HIP 31021, HIP 64732, HIP 73780 were found to be spectroscopic binary stars, while HIP 19072, HIP 67651 and HIP 75636 are also likely to be binaries and HIP 33111 could even be a triple system. Magnetic fields were detected on a number of the survey stars: HIP 21632, HIP 43720, HIP 48770, HIP 62517, HIP 71933, HIP 77144, HIP 89829, HIP 90899 and HIP 105388, making these stars good candidates for follow-up Zeeman Doppler imaging studies.

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“…The rate of this secular evolution may be modified, either increased or reduced, by so-called nonstandard transport processes, such as rotational mixing, internal magnetic fields, gravity waves, or tidal interactions and by structural changes induced by, for instance, rotation, magnetic activity, metallicity, or accretion (e.g., Pinsonneault et al 1990;Zahn 1992;Ventura et al 1998;Piau & Turck-Chièze 2002;Talon & Charbonnel 2005;Denissenkov 2010;Eggenberger et al 2012;Théado & Vauclair 2012). These additional processes may vary from star to star, depending on initial conditions and specific evolutionary paths and, thus, have the potential to produce an enhanced lithium spread Full Table 1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A78 in otherwise similar stars at the same age (e.g., Pasquini et al 2008;Do Nascimento et al 2010;Ramírez et al 2012).…”

Section: Introductionmentioning

confidence: 99%

TheGaia-ESO Survey: A lithium-rotation connection at 5 Myr?

Bouvier

Lanzafame

Venuti

et al. 2016

A&A

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Context. The evolution of lithium abundance in cool dwarfs provides a unique probe of nonstandard processes in stellar evolution. Aims. We investigate the lithium content of young low-mass stars in the 5 Myr old, star forming region NGC 2264 and its relationship with rotation. Methods. We combine lithium equivalent width measurements (EW(Li)) from the Gaia-ESO Survey with the determination of rotational periods from the CSI 2264 survey. We only consider bona fide nonaccreting cluster members to minimize the uncertainties on EW(Li). Results. We report the existence of a relationship between lithium content and rotation in NGC 2264 at an age of 5 Myr. The Li-rotation connection is seen over a restricted temperature range (T eff = 3800-4400 K), where fast rotators are Li-rich compared to slow rotators. This correlation is similar to, albeit of lower amplitude than, the Li-rotation connection previously reported for K dwarfs in the 125 Myr old Pleiades cluster. We investigate whether the nonstandard pre-main-sequence models developed so far to explain the Pleiades results, which are based on episodic accretion, pre-main-sequence, core-envelope decoupling, and/or radius inflation due to enhanced magnetic activity, can account for early development of the Li-rotation connection. While radius inflation appears to be the most promising possibility, each of these models has issues. We therefore also discuss external causes that might operate during the first few Myr of pre-main-sequence evolution, such as planet engulfment and/or steady disk accretion, as possible candidates for the common origin for Li excess and fast rotation in young low-mass pre-main-sequence stars. Conclusions. The emergence of a connection between lithium content and rotation rate at such an early age as 5 Myr suggests a complex link between accretion processes, early angular momentum evolution, and possibly planet formation, which likely impacts early stellar evolution and has yet to be fully deciphered.

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Rotation and lithium abundance of solar-analog stars

Cited by 15 publications

References 32 publications

Improved angular momentum evolution model for solar-like stars

Improved angular momentum evolution model for solar-like stars

High-resolution Spectroscopy and Spectropolarimetry of Some Late F- / Early G-type Sun-like Stars as Targets for Zeeman Doppler Imaging

TheGaia-ESO Survey: A lithium-rotation connection at 5 Myr?

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