English
Related papers

Related papers: First detection of linear polarization in the line…

200 papers

Magnetic fields of cool active stars are currently studied polarimetrically using only circular polarization observations. Including linear polarization in the reconstruction of stellar magnetic fields allows more information about the…

Solar and Stellar Astrophysics · Physics 2013-08-30 L. Rosén , O. Kochukhov , G. A. Wade

Here we report on the first detection of circular polarization in molecular lines formed in cool magnetic regions (starspots) and in chromospheric emission lines formed in hot plages on the surfaces of active stars. Our survey of G-K-M…

Astrophysics · Physics 2007-05-23 S. V. Berdyugina , D. M. Fluri , N. Afram , F. Suwald , P. Petit , J. Arnaud , D. M. Harrington , J. R. Kuhn

We report on the first ever detection of circular polarization in molecular lines forming in magnetic regions on the surfaces of active stars. The new observations were obtained with the high-resolution spectropolarimeter ESPaDOnS recently…

Astrophysics · Physics 2007-05-23 S. V. Berdyugina , P. Petit , D. M. Fluri , N. Afram , J. Arnaud

Magnetic fields in cool stars are ubiquitous but can still be challenging to characterize due to their complexity and relatively low strength. The polarization signature amplitudes are proportional to the field strength, and current studies…

Solar and Stellar Astrophysics · Physics 2014-08-19 L. Rosén , O. Kochukhov , G. A. Wade

Magnetic fields are ubiquitous in active cool stars but they are in general complex and weak. Current Zeeman Doppler imaging (ZDI) studies of cool star magnetic fields chiefly employ circular polarization observations because linear…

Solar and Stellar Astrophysics · Physics 2015-06-03 Lisa Rosén , Oleg Kochukhov , Gregg A. Wade

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

We present recent polarimetric results of magnetically active late-type dwarfs. The polarization in these stars is found to be wavelength dependent, decreasing towards the longer wavelength. The average values of degree of polarization in…

Solar and Stellar Astrophysics · Physics 2016-02-08 Manoj K. Patel , Jeewan C. Pandey , Subhajeet Karmakar , D. C. Srivastava , Igor S. Savanov

Several arguments have been presented that favour a scenario in which the low detection rate of magnetic fields in Herbig Ae stars can be explained by the weakness of these fields and rather large measurement uncertainties.…

Solar and Stellar Astrophysics · Physics 2015-11-02 S. P. Järvinen , T. A. Carroll , S. Hubrig , M. Schöller , I. Ilyin , H. Korhonen , M. Pogodin , N. A. Drake

A method for the determination of integrated longitudinal stellar fields from low-resolution spectra is the so-called slope method, which is based on the regression of the Stokes V signal against the first derivative of Stokes I. Here we…

Solar and Stellar Astrophysics · Physics 2017-08-18 C. Scalia , F. Leone , M. Gangi , M. Giarrusso , M. J. Stift

Many active stars are covered in spots, much more so than the Sun, as indicated by spectroscopic and photometric observations. It has been predicted that star spots induce non-zero intrinsic linear polarization by breaking the visible…

Solar and Stellar Astrophysics · Physics 2018-05-16 T. M. Yakobchuk , S. V. Berdyugina

We report observations of the linear polarisation of a sample of 50 nearby southern bright stars measured to a median sensitivity of $\sim$4.4 $\times 10^{-6}$. We find larger polarisations and more highly polarised stars than in the…

Solar and Stellar Astrophysics · Physics 2017-03-29 Daniel V. Cotton , Jeremy Bailey , Lucyna Kedziora-Chudczer , Kimberly Bott , P. W. Lucas , J. H. Hough , Jonathan P. Marshall

High-resolution spectropolarimetric observations provide simultaneous information about stellar magnetic field topologies and three-dimensional distributions of chemical elements. Here we present analysis of a unique full Stokes vector…

The near-star environment around obscured stars is very dynamic. Many classes of stars show evidence for winds, disks, inflows and outflows with many phenomena occurring simultaneously. These processes are involved in stellar evolution,…

Astrophysics · Physics 2008-09-22 D. M. Harrington , J. R. Kuhn

Mapping magnetic fields is the key to resolving what remains an unclear physical picture of circumstellar magnetic fields in late-type evolved stars. Observations of linearly polarized emission from thermal molecular line transitions due to…

Solar and Stellar Astrophysics · Physics 2020-09-02 K. -Y. Huang , A. J. Kemball , W. H. T. Vlemmings , S. -P. Lai , L. Yang , I. Agudo

The polarization of light across individual spectral lines contains information about the circumstellar environment on very small spatial scales. We have obtained a large number of high precision, high resolution spectropolarimetric…

Astrophysics · Physics 2009-11-13 D. M. Harrington , J. R. Kuhn

Ellerman bombs are bright emission features observed in the wings of H$\alpha$, usually in the vicinity of magnetic concentrations. Here we show that they can also be detected in the Ca II infrared triplet lines, which are easier to…

Aims. We aim at studying the near infrared linear polarization signal of rapidly rotating ultracool dwarfs with spectral types ranging from M7 through T2 and projected rotational velocities vsini >= 30 km s^{-1}. All these dwarfs are…

Solar and Stellar Astrophysics · Physics 2015-06-16 Paulo Alberto Miles-Páez , María Rosa Zapatero Osorio , Enric Pallé , Karla Peña Ramírez

We report on polarimetric observations of 100 pulsars centered on 774 MHz, made using the Green Bank Telescope, presenting their polarization profiles and polarized flux densities and comparing them with previous observations when possible.…

Solar and Stellar Astrophysics · Physics 2009-03-25 J. L. Han , P. B. Demorest , W. van Straten , A. G. Lyne

We conducted a Very Large Array survey of eleven low luminosity active galactic nuclei for linear and circular polarization at 8.4 GHz. We detected circular polarization in one source (M81*) and linear polarization in 3 sources. Sensitivity…

Astrophysics · Physics 2009-11-07 Geoffrey C. Bower , Heino Falcke , Richard R. Mellon

Optical spectropolarimetry of the nucleus of the LINER NGC 1052, obtained at the Keck Observatory, reveals a rise in polarization in the wings of the H-alpha line profile. The polarization vector of H-alpha is offset by 67 degrees from the…

Astrophysics · Physics 2009-10-31 A. J. Barth , A. V. Filippenko , E. C. Moran
‹ Prev 1 2 3 10 Next ›