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Related papers: Pollux: A weak dynamo-driven dipolar magnetic fiel…

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We report magnetic and spectroscopic observations and modeling of the Of?p star CPD -28 2561. Using more than 75 new spectra, we have measured the equivalent width variations and examined the dynamic spectra of photospheric and…

We have used NSF's Karl G. Jansky Very Large Array (VLA) to observe a sample of five known radio-emitting late L and T dwarfs ranging in age from ~0.2 - 3.4Gyr. We observed each target for seven hours, extending to higher frequencies than…

Solar and Stellar Astrophysics · Physics 2018-08-09 Melodie Kao , Gregg Hallinan , J. Sebastian Pineda , David Stevenson , Adam Burgasser

Some of the white dwarfs exhibit among the strongest magnetic fields in the universe. Many of these degenerate magnetic stars are also rotating very slowly. Among these objects, Grw+70$^\circ$\,8247, with its century-long suspected rotation…

Solar and Stellar Astrophysics · Physics 2019-05-01 Stefano Bagnulo , John D. Landstreet

We studied possible evolution of the rotational period and the magnetic field of the X-ray source RX J0720.4-3125 assuming this source to be an isolated neutron star accreting interstellar medium. Magnetic field of the source is estimated…

Astrophysics · Physics 2009-10-30 D. Yu. Konenkov , S. B. Popov

We considered variations the dipole and the quadrupole components of the solar large-scale magnetic field. Both the axial and the equatorial dipoles exhibit a systematic decrease in the past four cycles in accordance with the general…

Solar and Stellar Astrophysics · Physics 2020-02-19 V. N. Obridko , D. D. Sokoloff , B. D. Shelting , A. S. Shibalova , I. M. Livshits

In this paper we describe a Bayesian statistical method designed to infer the magnetic properties of stars observed using high-resolution circular spectropolarimetry in the context of large surveys. This approach is well suited for…

Solar and Stellar Astrophysics · Physics 2015-06-03 V. Petit , G. A. Wade

In this paper, we study six slowly rotating mid-to-late M~dwarfs (rotation period $P_{\mathrm{rot}} \approx 40-190\,\mathrm{dy}$) by analysing spectropolarimetric data collected with SPIRou at the Canada-France-Hawaii Telescope as part of…

Solar and Stellar Astrophysics · Physics 2023-11-10 L. T. Lehmann , J. -F. Donati , P. Fouque , C. Moutou , S. Bellotti , X. Delfosse , P. Petit , A. Carmona , J. Morin , A. A. Vidotto , the SLS consortium

There is an intricate relationship between the organization of large-scale magnetic fields by a stellar dynamo and the rate of angular momentum loss due to magnetized stellar winds. An essential ingredient for the operation of a large-scale…

The Sun's polar magnetic fields are directly related to solar cycle variability. The strength of the polar fields at the start (minimum) of a cycle determine the subsequent amplitude of that cycle. In addition, the polar field reversals at…

Solar and Stellar Astrophysics · Physics 2014-08-01 Lisa Upton , David H. Hathaway

In the past two decades, the observed large-scale magnetic field of the active M dwarf star AD Leo has evolved from strongly to mildly negative, raising a suspicion that it might switch polarity. Although magnetic field reversals are…

Solar and Stellar Astrophysics · Physics 2026-02-23 K. G. Smith , D. Evensberget , S. Bellotti , J. Morin , A. A. Vidotto , B. J. S. Pope

The MiMeS project demonstrated that a small fraction of massive stars (around 7%) presents large-scale, stable, generally dipolar magnetic fields at their surface. They are supposed to be fossil remnants of initial phases of stellar…

Solar and Stellar Astrophysics · Physics 2015-06-22 Constance Emeriau , Stéphane Mathis

Magnetic fields have been measured recently in the core of red giant stars thanks to their effects on stellar oscillation frequencies. The search for magnetic signatures in pulsating stars, such as $\gamma$ Doradus or Slowly Pulsation B…

Solar and Stellar Astrophysics · Physics 2023-11-23 François Lignières , Jérôme Ballot , Sébastien Deheuvels , Marion Galoy

Although systematic measurements of the solar polar magnetic field exist only from mid 1970s, other proxies can be used to infer the polar field at earlier times. The observational data indicate a strong correlation between the polar field…

Astrophysics · Physics 2009-11-13 Jie Jiang , Piyali Chatterjee , Arnab Rai Choudhuri

There is growing evidence, based on both X-ray and radio observations of isolated neutron stars, that besides the large--scale (dipolar) magnetic field, which determines the pulsar spin--down behaviour, small--scale poloidal field…

Astrophysics · Physics 2009-11-10 U. Geppert , M. Rheinhardt , J. Gil

Strong, globally-organized magnetic fields are found for a small fraction of O, B, and A stars. At the same time, many theoretical and indirect observational studies suggested ubiquitous presence of weak localized magnetic fields at the…

Solar and Stellar Astrophysics · Physics 2015-06-15 O. Kochukhov , N. Sudnik

AD Leonis is a nearby magnetically active M dwarf. We find Doppler variability with a period of 2.23 days as well as photometric signals: (1) a short period signal which is similar to the radial velocity signal albeit with considerable…

Earth and Planetary Astrophysics · Physics 2018-05-02 Mikko Tuomi , Hugh R. A. Jones , Guillem Anglada-Escudé , R. Paul Butler , Marcin Kiraga , Steven S. Vogt

There is a large change in surface rotation rates of sun-like stars on the pre-main sequence and early main sequence. Since these stars have dynamo driven magnetic fields, this implies a strong evolution of their magnetic properties over…

Solar and Stellar Astrophysics · Physics 2018-01-10 C. P. Folsom , J. Bouvier , P. Petit , A. Lèbre , L. Amard , A. Palacios , J. Morin , J. -F. Donati , A. A. Vidotto

The continuous high-precision photometric observations provided by the CoRoT and Kepler space missions have allowed us to better understand the structure and dynamics of red giants using asteroseismic techniques. A small fraction of these…

Geomagnetism is characterized by intermittent polarity reversals and rapid fluctuations. We have recently proposed a coupled macro-spin model to describe these dynamics based on the idea that the whole dynamo mechanism is described by the…

Earth and Planetary Astrophysics · Physics 2015-05-28 A. Nakamichi , H. Mouri , D. Schmitt , A. Ferriz-Mas , J. Wicht , M. Morikawa

M dwarfs are low-mass main-sequence stars, the most numerous type of stars in the solar neighbourhood, which are known to have significant magnetic activity. The aim of this work is to explore the dynamo solutions and magnetic fields of…

Solar and Stellar Astrophysics · Physics 2022-06-29 Carolina A. Ortiz-Rodríguez , Dominik R. G. Schleicher , Petri J. Käpylä , Felipe H. Navarrete