The BRITE spectropolarimetric program

Neiner, Coralie; Wade, Gregg; Marsden, Stephen; Blazère, Aurore

doi:10.48550/arxiv.1611.03285

Cited by 5 publications

(6 citation statements)

References 15 publications

(18 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Over the last two decades, magnetic fields have been steadily detected for massive stars with spectral type earlier than B3. This is in large part thanks to the detailed spectropolarimetric surveys that systematically search for such magnetic fields in carefully selected samples that depend on their respective objectives (MiMeS, Wade et al (2016); BinaMIcS, Alecian et al (2015); the BOB campaign, Morel et al (2015); and the BRITE spectropolarimetric survey, Neiner et al (2016)). In other cases, magnetic fields were discovered from indirect observational evidence, such as rotational modulation of X-ray emission, UV resonance lines or Hα emission.…”

Section: The Effect Of Magnetism In Early-type Starsmentioning

confidence: 99%

Magnetic characterization of the SPB/β Cep hybrid pulsator HD 43317

Buysschaert

Neiner

Briquet

et al. 2017

A&A

View full text Add to dashboard Cite

Large-scale magnetic fields at the surface of massive stars do not only influence the outer-most layers of the star, but also have consequences for the deep interior, only observationally accessible through asteroseismology. We performed a detailed characterization of the dipolar magnetic field at the surface of the B3.5V star HD 43317, a SPB/β Cep hybrid pulsator, by studying the rotationally modulated magnetic field of archival and new Narval spectropolarimetry. Additionally, we employed a grid-based approach to compare the Zeeman signatures with model profiles. By studying the rotational modulation of the He lines in both the Narval and HARPS spectroscopy caused by co-rotating surface abundance inhomogeneities, we updated the rotation period to 0.897673 ± 0.000004 d. The inclination angle between the rotation axis and the observer's line of sight remains ill-defined, because of the low level of variability in Stokes V and deformations in the intensity profiles by stellar pulsation modes. The obliquity angle between the rotation and magnetic axes is constrained to β ∈ [67, 90] • , and the strength of the dipolar magnetic field is of the order of 1 kG to 1.5 kG. This magnetic field at the stellar surface is sufficiently strong to warrant a uniformly rotating radiative envelope, causing less convective core overshooting, which should be visible in future forward seismic modeling.

show abstract

Section: The Effect Of Magnetism In Early-type Starsmentioning

confidence: 99%

Magnetic characterization of the SPB/β Cep hybrid pulsator HD 43317

Buysschaert

Neiner

Briquet

et al. 2017

A&A

View full text Add to dashboard Cite

show abstract

“…N allows to check for signal due to instrumental effects or stellar phenomena unrelated to magnetism, such as pulsations. β Cas was observed a first time on November 3, 2013, as a part of the BRITEpol survey (Neiner et al 2016). BRITEpol measures the potential magnetic field of all stars brighter than V = 4 mag, as a ground-based support to BRITE.…”

Section: Narval Spectropolarimetric Observationsmentioning

confidence: 99%

beta Cas: the first delta Scuti star with a dynamo magnetic field

Zwintz,

Neiner,

Kochukhov

et al. 2020

Preprint

View full text Add to dashboard Cite

Context. F type stars are characterised by several physical processes such as different pulsation mechanisms, rotation, convection, diffusion, and magnetic fields. The rapidly rotating δ Scuti star β Cas can be considered as a benchmark star to study the interaction of several of these effects. Aims. We investigate the pulsational and magnetic field properties of β Cas. We also determine the star's apparent fundamental parameters and chemical abundances. Methods. Based on photometric time series obtained from three different space missions (BRITE-Constellation, SMEI, and TESS), we conduct a frequency analysis and investigate the stability of the pulsation amplitudes over four years of observations. We investigate the presence of a magnetic field and its properties using spectropolarimetric observations taken with the Narval instrument by applying the Least Square Deconvolution and Zeeman Doppler Imaging techniques. Results. β Cas shows only three independent p-mode frequencies down to the few ppm-level; its highest amplitude frequency is suggested to be a n = 3, = 2, m = 0 mode. Its magnetic field structure is quite complex and almost certainly of a dynamo origin. β Cas' atmosphere is slightly deficient in iron peak elements and slightly overabundant in C, O, and heavier elements. Conclusions. Atypically for δ Scuti stars, we can only detect three pulsation modes down to exceptionally low noise levels for β Cas. The star is also one of very few δ Scuti pulsators known to date to show a measurable magnetic field, and the first δ Scuti star with a dynamo magnetic field. These characteristics make β Cas an interesting target for future studies of dynamo processes in the thin convective envelopes of F-type stars, of the transition region between fossil and dynamo fields, and the interaction between pulsations and magnetic field.

show abstract

“…In response to this substantial endeavor, a coinciding magnitude-limited survey was planned to observe each BRITE target using the technique of spectropolarimetry, to deduce the incidence of magnetism across all spectral types. The BRITE spectropolarimetric (BRITEpol) survey (Neiner et al 2016) aims to observe ∼600 stars with 3 high-resolution spectropolarimetric instruments: HARPSpol (R∼100,000) at the 3.6-m ESO telescope in Chile, Narval (R∼68,000) at Téléscope Bernard Lyot (TBL) in France, and ESPaDOnS (R∼68,000) at the Canada-France-Hawaii Telescope (CFHT) in Hawaii. By observing a single circular polarization spectrum or Stokes V spectrum, the presence of a magnetic field can be detected, followed up with a second observation for confirmation.…”

Section: Britepol Surveymentioning

confidence: 99%

The evolution of magnetic fields in hot stars

et al. 2016

Self Cite

View full text Add to dashboard Cite

Over the last decade, tremendous strides have been achieved in our understanding of magnetism in main sequence hot stars. In particular, the statistical occurrence of their surface magnetism has been established (~10%) and the field origin is now understood to be fossil. However, fundamental questions remain: how do these fossil fields evolve during the post-main sequence phases, and how do they influence the evolution of hot stars from the main sequence to their ultimate demise? Filling the void of known magnetic evolved hot (OBA) stars, studying the evolution of their fossil magnetic fields along stellar evolution, and understanding the impact of these fields on the angular momentum, rotation, mass loss, and evolution of the star itself, is crucial to answering these questions, with far reaching consequences, in particular for the properties of the precursors of supernovae explosions and stellar remnants. In the framework of the BRITE spectropolarimetric survey and LIFE project, we have discovered the first few magnetic hot supergiants. Their longitudinal surface magnetic field is very weak but their configuration resembles those of main sequence hot stars. We present these first observational results and propose to interpret them at first order in the context of magnetic flux conservation as the radius of the star expands with evolution. We then also consider the possible impact of stellar structure changes along evolution.Comment: 5 pages, 2 figures, IAUS 329 conference proceedin

show abstract

The BRITE spectropolarimetric program

Cited by 5 publications

References 15 publications

Magnetic characterization of the SPB/β Cep hybrid pulsator HD 43317

Magnetic characterization of the SPB/β Cep hybrid pulsator HD 43317

beta Cas: the first delta Scuti star with a dynamo magnetic field

The evolution of magnetic fields in hot stars

Contact Info

Product

Resources

About