New Longitudinal Magnetic Field Measurements of the Periodic X-Ray Variable ρ Oph A

AbstractWe present the preliminary results of the measurements of longitudinal magnetic field of the massive white dwarf 1658+441. This star have an hydrogen pure atmosphere (e.g. Dupuis & Chayer, 2003). We have observed the target in a total of 18 hrs during 3 consecutive nights in June 2010 and one more in May 2011. The data was acquired with a prototypical spectropolarimeter at the San Pedro Martir Telescope in Mexico. We have tested the magnetic field measurements with our instrument using the famous Babcock's star obtaining consistent results with previous studies. For our object of study, the WD 1658+441, we have measured variable intensities of the longitudinal magnetic field of Blong = 720 kG that oscillates with an amplitude of 130 kG.

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Two Kinds of Activity in Late-type Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100080106 ◽

1991 ◽

Vol 130 ◽

pp. 440-442

Author(s):

M.M. Katsova

Keyword(s):

Magnetic Field ◽

Active Regions ◽

Field Measurements ◽

Spherically Symmetric ◽

The Sun ◽

Late Type ◽

X Ray ◽

Magnetic Field Measurements ◽

Local Magnetic Fields ◽

Uniform Manner

Several years ago we proposed a method for the analysis of X-ray observations of late-type stars. It allowed the determination in a uniform manner of coronal base electron densities for more than 40 late-type stars, in terms of a one-temperature consideration of homogeneous spherically symmetric coronae (Katsova et al., 1987). Fig. 1 shows the results as a function of spectral type. Comparison of our results with values for different kinds of solar regions shows that physical characteristics of F and G star coronae correspond to densities less than those in active regions on the Sun. Values for the active K-M0 stars are comparable with those of dense steady condensations found directly above large sunspots.On this basis, activity can be explained as an increase in that part of the stellar surface that is occupied by strong local magnetic fields. This is illustrated in the table where we compare magnetic field measurements by Saar and Linsky (1988) with our calculations.

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ξ1CMa: An Extremely Slowly Rotating Magnetic B0.7 IV Star

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314007261 ◽

2014 ◽

Vol 9 (S307) ◽

pp. 399-400 ◽

Cited By ~ 1

Author(s):

Matt Shultz ◽

Gregg Wade ◽

Thomas Rivinius ◽

Wagner Marcolino ◽

Huib Henrichs ◽

...

Keyword(s):

Magnetic Field ◽

Angular Momentum ◽

Absorption Line ◽

Longitudinal Magnetic Field ◽

Field Measurements ◽

Line Profiles ◽

Rotational Period ◽

Magnetic Field Measurements ◽

Angular Momentum Loss ◽

Best Fit

AbstractWe present our analysis of 6 years of ESPaDOnS spectropolarimetry of the magnetic β Cep star ξ1CMa (B1 III). This high-precision magnetometry is consistent with a rotational periodProt> 40 yr. Absorption line profiles can be reproduced with a non-rotating model. We constrainR⋆,L⋆, and the stellar age via a Baade-Wesselink analysis. Spindown due to angular momentum loss via the magnetosphere predicts an extremely long rotational period if the magnetic dipoleBd> 6 kG, a strength also inferred by the best-fit sinusoids to the longitudinal magnetic field measurementsBZwhen phased with a 60-yearProt.

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Magnetic Models Can Not Explain The Blazhko Effect in RR Lyrae Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100011283 ◽

2004 ◽

Vol 193 ◽

pp. 535-538

Author(s):

M. Chadid ◽

S.L.S. Shorlin ◽

J.D. Landstreet

Keyword(s):

Magnetic Field ◽

Longitudinal Magnetic Field ◽

Field Measurements ◽

Magnetic Star ◽

Rr Lyrae Stars ◽

Rr Lyrae ◽

Magnetic Field Measurements ◽

Blazhko Effect ◽

Bona Fide ◽

Lyrae Stars

AbstractWe report a new series of high-precision Stokes V profiles and longitudinal magnetic field measurements of RR Lyrae, obtained with the MuSiCoS spectropolarimeter over a period of four years. These data provide no evidence whatsoever for a strong magnetic field in the photosphere of RRLyrae, which is consistent with Preston’s (1967) results, but inconsistent with apparent magnetic field detections by Babcock (1958) and Romanov et al. (1987, 1994). Following discussion of these disparate results, we conclude that RR Lyrae is a bona fide non-magnetic star, a conclusion which leads to the general falsification of models of the Blazkho effect requiring strong photospheric magnetic fields.

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