Systematic detection of magnetic fields in massive, late-type supergiants

Abstract

We report the systematic detection of magnetic fields in massive (M > 5 M${}_{\odot }$) late-type supergiants, using spectropolarimetric observations obtained with ESPaDOnS at the Canada-France-Hawaii Telescope. Our observations reveal detectable Stokes V Zeeman signatures in Least-Squares Deconvolved mean line profiles in one-third of the observed sample of more than 30 stars. The signatures are sometimes complex, revealing multiple reversals across the line. The corresponding longitudinal magnetic field is seldom detected, although our longitudinal field error bars are typically 0.3 G ($1\sigma$). These characteristics suggest topologically complex magnetic fields, presumably generated by dynamo action. The Stokes V signatures of some targets show clear time variability, indicating either rotational modulation or intrinsic evolution of the magnetic field. We also observe a weak correlation between the unsigned longitudinal magnetic field and the CaII K core emission equivalent width of the active G2Iab supergiant $\beta$~Dra and the G8Ib supergiant $\epsilon$~Gem.

8 pages, 1 table, 6 figures, accepted for publication in MNRAS

References in corpus (5)

• The magnetic field of Betelgeuse: a local dynamo from giant convection cells?
• On the Enhancement of Mass Loss in Cepheids Due to Radial Pulsation
• Cepheid Mass-loss and the Pulsation -- Evolutionary Mass Discrepancy
• EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars
• Massive stars in their death-throes

Cited by in corpus (36)

• Radiative hydrodynamics simulations of red supergiant stars. IV gray versus non-gray opacities
• What causes the large extensions of red-supergiant atmospheres? Comparisons of interferometric observations with 1-D hydrostatic, 3-D convection, and 1-D pulsating model atmospheres
• High spectral resolution imaging of the dynamical atmosphere of the red supergiant Antares in the CO first overtone lines with VLTI/AMBER
• The effects of surface fossil magnetic fields on massive star evolution: I. Magnetic field evolution, mass-loss quenching and magnetic braking
• Modeling of Magneto-Rotational Stellar Evolution I. Method and first applications
• Magnetic fields in massive stars, their winds, and their nebulae
• Search for surface magnetic fields in Mira stars. First detection in chi Cyg
• Discovery of Cycle-to-cycle Modulated Spectral Line Variability and Velocity Gradients in Long-period Cepheids
• The importance of non-photon noise in stellar spectropolarimetry. The spurious detection of a non-existing magnetic field in the A0 supergiant HD 92207
• Jet Formation in 3D GRMHD Simulations of Bondi-Hoyle-Lyttleton Accretion
• Measuring surface magnetic fields of red supergiant stars
• The Secret Lives of Cepheids: $\delta$ Cep -- the Prototype of a New Class of Pulsating X-ray Variable Stars
• CHARA/MIRC observations of two M supergiants in Perseus OB1: temperature, Bayesian modeling, and compressed sensing imaging
• First results from the LIFE project: discovery of two magnetic hot evolved stars
• Blue supergiants as descendants of magnetic main sequence stars
• Evolution of the magnetic field of Betelgeuse from 2009 - 2017
• Discovery of magnetic A supergiants: the descendants of magnetic main sequence B stars
• Discovery of an extremely weak magnetic field in the white dwarf LTT 16093 = WD2047+372
• A catalog of rotational and radial velocities for evolved stars V. Southern stars
• Improvements in the determination of ISS Ca II K parameters
• Red Supergiant Candidates for Multimessenger Monitoring of the Next Galactic Supernova
• Magnetic field and convection in the cool supergiant Betelgeuse
• A search for strong magnetic fields in massive and very massive stars in the Magellanic Clouds
• Simultaneous VLBA polarimetric observations of the v=$\{$1,2$\}$ J=1-0 and v=1, J=2-1 SiO maser emission toward VY CMa II: component-level polarization analysis
• Detection of the 128 day radial velocity variations in the supergiant α Persei. Rotational modulations, pulsations, or a planet?
• Detecting and quantifying stellar magnetic fields -- Sparse Stokes profile approximation using orthogonal matching pursuit
• UVMag: stellar formation, evolution, structure and environment with space UV and visible spectropolarimetry
• Finding magnetic north: an extraordinary magnetic field detection in Polaris and first results of a magnetic survey of classical Cepheids
• X-rays in Cepheids: XMM-Newton Observations of $\eta$ Aql
• Polarization position angle standard stars: a reassessment of $\theta$ and its variability for seventeen stars based on a decade of observations
• Spectropolarimetric study of the classical Cepheid $\eta$ Aql: pulsation and magnetic field
• A Multi-Year Photopolarimetric Study of the Semi-Regular Variable V CVn and Identification of Analogue Sources
• Searching for Magnetic Fields in the Descendants of Massive OB Stars
• Stellar Magnetism
• Magnetic field of the classical Cepheid $\eta$ Aql: new results
• Spectropolarimetry of massive stars: Requirements and potential from today to 2030