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Khomenko et al. estimate the mean magnetic field strength of the quiet Sun to be 20 G. The figure is smaller than several existing estimates, and it comes from the comparison between observed Zeeman polarization signals and synthetic…

Astrophysics · Physics 2009-11-11 J. Sanchez Almeida

The bright A-type metallic-line star o Peg was reported in the early 1990s to have a surface magnetic field of ~2kG by analyzing the widths and strengths of spectral lines. In respect that those old studies were of rather empirical or…

Solar and Stellar Astrophysics · Physics 2023-05-03 Yoichi Takeda

Context. Investigations of the magnetism of the quiet Sun are hindered by extremely weak polarization signals in Fraunhofer spectral lines. Photon noise, straylight, and the systematically different sensitivity of the Zeeman effect to…

Parker Solar Probe and Solar Orbiter data are used to investigate the radial evolution of magnetic turbulence between $0.06 ~ \lesssim R ~\lesssim 1$ au. The spectrum is studied as a function of scale, normalized to the ion inertial scale…

A large-scale, horse-shoe-like filament was investigated and the magnetic field around it was reconstructed. This is an intermediate filament (IF) that appeared on the solar disk for the first time at 02:00 UT on 2015 November 7, and took 8…

Solar and Stellar Astrophysics · Physics 2022-11-16 Kaifeng Kang , Yang Guo , Ilia I. Roussev , Rony Keppens , Jun Lin

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

The large-scale magnetic field of solar-type stars reconstructed from their spectropolarimetric observations provide important insight into their underlying dynamo processes.We aim to investigate the temporal variability of the large-scale…

Solar and Stellar Astrophysics · Physics 2014-12-10 S. Boro Saikia , S. V. Jeffers , P. Petit , S. Marsden , J. Morin , C. P. Folsom

We studied the physical parameters of the penumbra in a large and fully-developed sunspot, one of the largest over the last two solar cycles, by using full-Stokes measurements taken at the photospheric Fe I 617.3 nm and chromospheric Ca II…

Solar and Stellar Astrophysics · Physics 2019-03-20 Mariarita Murabito , I. Ermolli , F. Giorgi , M. Stangalini , S. L. Guglielmino , S. Jafarzadeh , H. Socas-Navarro , P. Romano , F. Zuccarello

We have carried out a statistical study of the average orientation of the magnetic field in solar filaments with respect to their axes for more than 400 samples, based on data taken with daily full-Sun, full-Stokes spectropolarimetric…

Solar and Stellar Astrophysics · Physics 2020-07-29 Yoichiro Hanaoka , Takashi Sakurai

We aim to evaluate how well the variation of small-scale magnetic fields on the stellar surface can be monitored with time-series observations. Further, we aim to establish to what extent the measured total unsigned magnetic field traces…

Solar and Stellar Astrophysics · Physics 2026-01-05 A. Hahlin , B. Zaire , C. P. Folsom , K. Al Moulla , A. Lavail

Advanced inversions of high-resolution spectropolarimetric observations of the He I triplet at 1083 nm are used to generate unique maps of the chromospheric magnetic field vector across a sunspot and its superpenumbral canopy. The…

Solar and Stellar Astrophysics · Physics 2015-08-06 T. A. Schad , M. J. Penn , H. Lin , A. Tritschler

Searches for small exoplanets around solar-type stars are limited by stellar physical variability. While chromospheric variability is well studied, observing, modeling. and understanding the much smaller fluctuations in photospheric…

Solar and Stellar Astrophysics · Physics 2024-07-03 Dainis Dravins , Hans-Günter Ludwig

This paper is an overview of studying the solar features in a complex network approach. First, we introduce the structural features of complex networks and important network parameters. Applying the detrended fluctuation and rescaled range…

Solar and Stellar Astrophysics · Physics 2024-10-15 Somayeh Taran

<b>Aims:</b> We analyse the magnetic field geometry of the magnetic DA white dwarf PG 1015+014 with our Zeeman tomography method.<br> <b>Methods:</b> This study is based on rotation-phase resolved optical flux and circular polarization…

Astrophysics · Physics 2016-08-15 F. Euchner , S. Jordan , K. Beuermann , K. Reinsch , B. T. Gaensicke

The solar chromosphere observed in H-alpha consists mostly of narrow fibrils. The longest typically originate in network or plage and arch far over adjacent internetwork. We use data from multiple telescopes to analyze one well-observed…

Solar and Stellar Astrophysics · Physics 2017-01-25 R. J. Rutten , L. H. M. Rouppe van der Voort

Early magnetographic observations indicated that magnetic field in the solar photosphere has unresolved small-scale structure. Near-infrared and optical data with extremely high spatial resolution show that these structures have scales of…

Solar and Stellar Astrophysics · Physics 2018-11-21 M. Gordovskyy. , S. Shelyag , P. K. Browning , V. G. Lozitsky

The quiet Sun photospheric plasma has a variety of magnetic field strengths going from zero to 1800 G. The empirical characterization of these field strengths requires a probability density function (PDF), i.e., a function P(B) describing…

Astrophysics · Physics 2009-11-13 I. Dominguez Cerdena , J. Sanchez Almeida , F. Kneer

While the magnetic field in quiescent prominences has been widely investigated, less is known about the field in activated prominences. We introduce observational results on the magnetic field structure of an activated filament in a flaring…

Solar and Stellar Astrophysics · Physics 2015-06-18 C. Sasso , A. Lagg , S. K. Solanki

We explore the photospheric and chromospheric magnetic field in an emerging flux region. An image of the equivalent width of the He I 10830 A red blended component shows the presence of filamentary structures that might be interpreted as…

Solar and Stellar Astrophysics · Physics 2010-01-14 A. Asensio Ramos , J. Trujillo Bueno

We present first quantitative results of the surface magnetic field measurements in selected M-dwarfs based on detailed spectra synthesis conducted simultaneously in atomic and molecular lines of the FeH Wing-Ford $F^4\,\Delta-X^4\,\Delta$…

Solar and Stellar Astrophysics · Physics 2015-05-19 D. Shulyak , A. Reiners , S. Wende , O. Kochukhov , N. Piskunov , A. Seifahrt