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Related papers: HD 76431 - An evolved hot subdwarf with variable m…

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We present the results of a study of the star HD 34736. The spectropolarimetric observations carried out at the 6-m telescope showed the presence of a strong variable longitudinal magnetic field, exceeding -4500 G. The analysis of the…

Solar and Stellar Astrophysics · Physics 2015-06-19 E. A. Semenko , I. I. Romanyuk , D. O. Kudryavtsev , I. A. Yakunin

Our ongoing spectroscopic survey of high proper motion stars is a rich source of new magnetic white dwarfs. We present a few examples among cool white dwarfs showing the effect of field strength and geometry on the observed optical…

Solar and Stellar Astrophysics · Physics 2018-01-18 S. Vennes , A. Kawka , L. Ferrario , E. Paunzen

Detection of magnetic fields has been reported in several sdO and sdB stars. Recent literature has cast doubts on the reliability of most of these detections. We revisit data previously published in the literature, and we present new…

Solar and Stellar Astrophysics · Physics 2015-06-04 John D Landstreet , Stefano Bagnulo , Luca Fossati , Stefan Jordan , Simon J O'Toole

We report on high-resolution spectropolarimetric observations of the hot subdwarf stars HD 76431 and Feige 66, using the ESPaDOnS echelle spectropolarimeter at CFHT. We compute cross-correlation Stokes I and V line profiles to enhance the…

Solar and Stellar Astrophysics · Physics 2011-10-26 P. Petit , V. Van Grootel , S. Bagnulo , S. Charpinet , G. A. Wade , E. M. Green

We present polarisation measurements of sdB and sdO stars using FORS1 on the VLT. The observations were made as part of a project to determine whether magnetic fields in two super-metal-rich stars can explain their extreme abundance…

Astrophysics · Physics 2009-11-10 S. J. O'Toole , S. Jordan , S. Friedrich , U. Heber

Strong advances in direct evidence of magnetic fields in hot massive stars have been possible thanks to the new generation of high-resolution spectropolarimeters such as ESPaDOnS (on the Canada-France-Hawaii Telescope) or HARPSpol (on the…

Solar and Stellar Astrophysics · Physics 2012-05-17 Evelyne Alecian

We present the results of measurements of magnetic fields, radial velocities and rotation velocities for 92 objects, mainly main-sequence chemically peculiar stars. Observations were performed at the 6-m BTA telescope using Main Stellar…

Solar and Stellar Astrophysics · Physics 2018-03-28 I. I. Romanyuk , E. A. Semenko , D. O. Kudryavtsev , A. V. Moiseeva , I. A. Yakunin

In the course of the Hamburg/ESO survey we have discovered a white dwarf whose spectrum exhibits many similarities with the prototype of magnetic white dwarfs Grw+70$^{\circ}$8247. In particular several stationary line components indicative…

Astrophysics · Physics 2007-05-23 Dieter Reimers , Stefan Jordan , Norbert Christlieb

Magnetic fields with strengths ranging from 300 to 500 kG have recently been discovered in a group of four extremely similar helium-enriched hot subdwarf (He-sdO) stars. Besides their strong magnetic fields, these He-sdO stars are…

Solar and Stellar Astrophysics · Physics 2024-11-13 M. Dorsch , C. S. Jeffery , A. Philip Monai , C. A. Tout , E. J. Snowdon , I. Monageng , L. J. A. Scott , B. Miszalski , V. M. Woolf

The extraordinary magnetic Ap star HD75049 has been studied with data obtained with the ESO VLT and 2.2-m telescopes. Direct measurements reveal that the magnetic field modulus at maximum reaches 30kG. The star shows photometric, spectral…

Solar and Stellar Astrophysics · Physics 2015-05-13 V. G. Elkin , G. Mathys , D. W. Kurtz , S. Hubrig , L. M. Freyhammer

About 10% of hot stars host a fossil magnetic field on the pre-main sequence and main sequence. However, the first magnetic evolved hot stars have been discovered only recently. An observing program has been set up to find more such…

Solar and Stellar Astrophysics · Physics 2018-11-14 C. Neiner , A. Martin , G. Wade , M. Oksala

HD 144941 is an extreme He (EHe) star, a rare class of subdwarf OB star formed from the merger of two white dwarf (WD) stars. Uniquely amongst EHe stars, its light curve has been reported to be modulated entirely by rotation, suggesting the…

Solar and Stellar Astrophysics · Physics 2021-08-04 M. E. Shultz , O. Kochukhov , J. Labadie-Bartz , A. David-Uraz , S. P. Owocki

Four magnetic white dwarfs have been found in the course of the Hamburg/ESO Survey for bright QSOs. The objects have been selected as QSO candidate on the basis of its blue continuum and the apparent absence of strong hydrogen or helium…

Astrophysics · Physics 2011-05-23 D. Reimers , S. Jordan , D. Koester , N. Bade , Th. Koehler , L. Wisotzki

HD189733 is an active K dwarf that is, with its transiting hot Jupiter, among the most studied exoplanetary systems. In this first paper of the Multiwavelength Observations of an eVaporating Exoplanet and its Star (MOVES) program, we…

We have conducted a survey of 61 southern white dwarfs searching for magnetic fields using Zeeman spectropolarimetry. Our objective is to obtain a magnetic field distribution for these objects and, in particular, to find white dwarfs with…

Astrophysics · Physics 2008-11-26 A. Kawka , S. Vennes , G. D. Schmidt , D. T. Wickramasinghe , R. Koch

Magnetic fields can play an important role in stellar evolution. Among white dwarfs, the most common stellar remnant, the fraction of magnetic systems is more than 20 per cent. The origin of magnetic fields in white dwarfs, which show…

Solar and Stellar Astrophysics · Physics 2022-04-27 Ingrid Pelisoli , M. Dorsch , U. Heber , B. Gänsicke , S. Geier , T. Kupfer , P. Németh , S. Scaringi , V. Schaffenroth

We have carried out a re-analysis of polarimetric data of central stars of planetary nebulae, hot subdwarfs, and white dwarfs taken with FORS1 (FOcal Reducer and low dispersion Spectrograph) on the VLT (Very Large Telescope), and added a…

Solar and Stellar Astrophysics · Physics 2012-10-16 S. Jordan , S. Bagnulo , J. Landstreet , L. Fossati , G. G. Valyanin , D. Monin , G. A. Wade , K. Werner , S. J. O'Toole

The early-type chemically peculiar stars often show strong magnetic fields on their surfaces. These magnetic topologies are organized on large scales and are believed to be close to an oblique dipole for most of the stars. In a striking…

Solar and Stellar Astrophysics · Physics 2015-05-20 Oleg Kochukhov , Andreas Lundin , Iosif Romanyuk , Dmitry Kudryavtsev

The presence of magnetic fields at the surfaces of many massive stars has been suspected for decades, to explain the observed properties and activity of OB stars. However, very few genuine high-mass stars had been identified as magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-20 V. Petit

Hot cluster Horizontal Branch (HB) stars and field subdwarf B (sdB) stars are core helium burning stars that exhibit abundance anomalies that are believed to be due to atomic diffusion. Diffusion can be effective in these stars because they…

Solar and Stellar Astrophysics · Physics 2015-06-03 G. Mathys , S. Hubrig , E. Mason , G. Michaud , M. Schoeller , F. Wesemael
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