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Related papers: Magnetic field evolution in solar-type stars

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In this paper we study radial oscillations of rotating strange stars in strong magnetic fields in the Density Dependent Quark Mass (DDQM) model. We see that increase of frequency i.e. difference in frequency of rotating and non-rotating…

Astrophysics · Physics 2007-05-23 S. Singh , N. Chandrika Devi , V. K. Gupta , Asha Gupta , J. D. Anand

Magnetic fields and stellar spots can alter the equivalent widths of absorption lines in stellar spectra, varying during the activity cycle. This also influences the information that we derive through spectroscopic analysis. In this study…

Grids of models for rotating stars are constructed in the range of 9 to 120 M$_{\odot}$ at solar metallicity. The following effects of rotation are included: shellular rotation, new structure equations for non-conservative case, surface…

Astrophysics · Physics 2008-11-26 Georges Meynet , Andre Maeder

We compare the current effects of rotation in stellar evolution to those of the magnetic field created by the Tayler instability. In stellar regions, where magnetic field can be generated by the dynamo due to differential rotation (Spruit…

Astrophysics · Physics 2009-11-10 Andre Maeder , Georges Meynet

Regardless of the physical origin of stellar magnetic fields - fossil or dynamo induced - an inclination angle between the magnetic and rotation axes is very often observed. Absence of observational evidence in this direction in the solar…

Solar and Stellar Astrophysics · Physics 2018-04-27 A. Pastor Yabar , M. J. Martínez González , M. Collados

The study of stellar activity is important because it can provide new constraints for dynamo models, when combined with surface rotation rates and the depth of the convection zone. We know that the dynamo mechanism, which is believed to be…

Solar and Stellar Astrophysics · Physics 2015-06-18 S. Mathur , R. A. Garcia , J. Ballot , T. Ceillier , D. Salabert , T. S. Metcalfe , C. Regulo , A. Jimenez , S. Bloemen

At metallicities lower than that of the Small Magellanic Cloud, it remains essentially unexplored how fossil magnetic fields, forming large-scale magnetospheres, could affect the evolution of massive stars, thereby impacting the fundamental…

Solar and Stellar Astrophysics · Physics 2024-07-31 Z. Keszthelyi , J. Puls , G. Chiaki , H. Nagakura , A. ud-Doula , T. Takiwaki , N. Tominaga

Observations of various solar-type stars along decades revealed that they can have magnetic cycles, just like our Sun. An investigation of the relation between their cycle length and rotation period can shed light on the dynamo mechanisms…

Solar and Stellar Astrophysics · Physics 2017-09-20 Raissa Estrela , Adriana Valio

Main-sequence massive stars possess convective cores that likely harbor strong dynamo action. To assess the role of core convection in building magnetic fields within these stars, we employ the 3-D anelastic spherical harmonic (ASH) code to…

Solar and Stellar Astrophysics · Physics 2015-05-20 Kyle C. Augustson , Allan S. Brun , Juri Toomre

Large-scale dipolar surface magnetic fields have been detected in a fraction of OB stars, however only few stellar evolution models of massive stars have considered the impact of these fossil fields. We are performing 1D hydrodynamical…

Solar and Stellar Astrophysics · Physics 2017-11-15 Z. Keszthelyi , G. A. Wade , V. Petit

Recent spectro-polarimetric observations of solar-type stars have shown the presence of photospheric magnetic fields with a predominant toroidal component. If the external field is assumed to be current-free it is impossible to explain…

Solar and Stellar Astrophysics · Physics 2016-12-21 Alfio Bonanno

One interpretation of the activity and magnetism of late-type stars is that these both intensify with decreasing Rossby number up to a saturation level, suggesting that stellar dynamos depend on both rotation and convective turbulence. Some…

Solar and Stellar Astrophysics · Physics 2020-03-23 Jyri J. Lehtinen , Federico Spada , Maarit J. Käpylä , Nigul Olspert , Petri J. Käpylä

For main-sequence stars beyond spectral type M5 the characteristics of magnetic activity common to warmer solar-like stars change into the brown-dwarf domain: the surface magnetic field becomes more dipolar and the evolution of the field…

Solar and Stellar Astrophysics · Physics 2011-02-11 C. J. Schrijver

The evolutionary scenario of the neutron star magnetic field is examined assuming a spindown-induced expulsion of magnetic flux originally confined to the core, in which case the expelled flux undergoes ohmic decay. The nature of field…

Astrophysics · Physics 2009-10-31 Sushan Konar , Dipankar Bhattacharya

The diagram of indices of coronal and chromospheric activity allowed us to reveal stars where solar-type activity appears and regular cycles are forming. Using new consideration of a relation between coronal activity and the rotation rate,…

Solar and Stellar Astrophysics · Physics 2015-08-06 M. M. Katsova , N. I. Bondar' , M. A. Livshits

The ever increasing level of precision achieved by present and future radial-velocity instruments is opening the way to discovering very low-mass, long-period planets (e.g. solar-system analogs). These systems will be detectable as…

Earth and Planetary Astrophysics · Physics 2015-05-14 N. C. Santos , J. Gomes da Silva , C. Lovis , C. Melo

The observed variability of the cosmic-ray intensity in the interplanetary space is driven by the evolution of the Sun's magnetic activity over its 11-year quasiperiodical cycle. Investigating the relationship between solar activity indices…

Solar and Stellar Astrophysics · Physics 2022-10-13 Nicola Tomassetti , Bruna Bertucci , Emanuele Fiandrini

Observations of surface magnetic fields of cool stars reveal a large diversity of configurations. Although there is now a consensus that these fields are generated through dynamo processes occurring within the convective zone, the physical…

Solar and Stellar Astrophysics · Physics 2022-10-05 B. Zaire , L. Jouve , T. Gastine , J-F. Donati , J. Morin , N. Landin , C. P. Folsom

Recent asteroseismic analyses have revealed the presence of strong (B $\gtrsim 10^5$ G) magnetic fields in the cores of many red giant stars. Here, we examine the implications of these results for the evolution of stellar magnetic fields,…

Solar and Stellar Astrophysics · Physics 2016-06-15 Matteo Cantiello , Jim Fuller , Lars Bildsten

Long-lived magnetic fields are known to exist in upper main-sequence stars, white dwarfs, and neutron stars. In order to explore possible equilibrium configurations of the magnetic field inside these stars, we have performed…

Solar and Stellar Astrophysics · Physics 2022-01-26 Laura Becerra , Andreas Reisenegger , Juan Alejandro Valdivia , Mikhail E. Gusakov