The MiMeS survey of magnetism in massive stars: introduction and overview

Abstract

The MiMeS (Magnetism in Massive Stars) project is a large-scale, high-resolution, sensitive spectropolarimetric investigation of the magnetic properties of O-and early B-type stars. Initiated in 2008 and completed in 2013, the project was supported by three Large Program allocations, as well as various programmes initiated by independent principal investigators, and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B stars were collected with the instruments ESPaDOnS (Echelle SpectroPolarimetric Device for the Observation of Stars) at the Canada-France-Hawaii Telescope, Narval at the Télescope Bernard Lyot and HARPSpol at the European Southern Observatory La Silla 3.6 m telescope, making MiMeS by far the largest systematic investigation of massive star magnetism ever undertaken. In this paper, the first in a series reporting the general results of the survey, we introduce the scientific motivation and goals, describe the sample of targets, review the instrumentation and observational techniques used, explain the exposure time calculation designed to provide sensitivity to surface dipole fields above approximately 100 G, discuss the polarimetric performance, stability and uncertainty of the instrumentation, and summarize the previous and forthcoming publications.

The effects of surface fossil magnetic fields on massive star evolution – II. Implementation of magnetic braking in mesa and implications for the evolution of surface rotation in OB stars

“…Magnetic fields are routinely detected in stars across the entire Hertzsprung-Russell diagram (HRD), from early to late evolutionary phases (Donati & Landstreet 2009). Surface magnetic fields are detected in 7% of hot, massive, OB stars (Wade et al 2014(Wade et al , 2016Martins et al 2015;Neiner et al 2015;Morel et al 2015;Fossati et al 2015;Grunhut et al 2017;Shultz et al 2018;Petit et al 2019). Unlike those E-mail: z.keszthelyi@uva.nl detected in cool stars, these surface fields are likely not being actively generated by a dynamo mechanism, especially because there is no evidence that extended convection zones 1 1 Hot stars do have thin sub-surface layers where inefficient convection (accounting for usually ≈ 3% of the energy transport) occurs due to the iron opacity bump (Cantiello et al 2009), and while there might perhaps be dynamo activity in those layers (Cantiello & Braithwaite 2011), that would not give rise to the strong, globally organized fields which are observed in magnetic OB stars.…”

Simulating Radio Emission from Low-mass Stars

“…Our understanding of how the dynamo magnetic field in fully convective, low-mass stars is generated is far from complete; however, magnetic imaging of bright, rapidly rotating stars through Zeeman Doppler Imaging (ZDI ;Semel 1989;Donati et al 1997Donati et al , 2006) is allowing us to study the topology and evolution of stellar magnetic fields for a wide range of stars, such as the pre-main sequence and main sequence through surveys such as BCool (solar-type stars; Marsden et al 2014), MAPP (classical T Tauri stars; Donati et al 2012), MiMeS (massive stars; Wade et al 2016), MaTYSSE (young planet hosting stars; Donati et al 2014), and BinaMIcS (short-period binary stars; Alecian et al 2015Alecian et al , 2016. To map the full magnetic topology of a star, polarized spectra are collected during at least one rotation of the star.…”

Evolving pulsation of the slowly rotating magnetic β Cep star ξ1 CMa

“…ESPaDOnS is an echelle spectropolarimeter with a high resolving power (λ/∆λ ∼ 65, 000), with a wavelength range of about 370 nm to 1000 nm, mounted at the Cassegrain focus of the 3.6 m Canada-France-Hawaii Telescope (CFHT). The instrument properties and data reduction were described in detail by Wade et al (2016). Each spectropolarimetric sequence consists of 4 differently spectra.…”