First HARPSpol discoveries of magnetic fields in massive stars

Alecian, E.; Kochukhov, O.; Neiner, C.; Wade, G. A.; de Batz, B.; Henrichs, H.; Grunhut, J. H.; Bouret, J.-C.; Briquet, M.; Gagne, M.; Naze, Y.; Oksala, M. E.; Rivinius, T.; Townsend, R. H. D.; Walborn, N. R.; Weiss, W.; Mimes Collaboration 
Astronomy & Astrophysics, Volume 536, id.L6, 4 pp.


In the framework of the Magnetism in Massive Stars (MiMeS) project, a HARPSpol Large Program at the 3.6m-ESO telescope has recently started to collect high-resolution spectropolarimetric data of a large number of Southern massive OB stars in the field of the Galaxy and in many young clusters and associations. We report on the first discoveries of magnetic fields in two massive stars with HARPSpol - HD 130807 and HD 122451, and confirm the presence of a magnetic field at the surface of HD 105382 that was previously observed with a low spectral resolution device. The longitudinal magnetic field measurements strongly vary for HD 130807 from ~-100 G to ~700 G. Those of HD 122451 and HD 105382 are less variable with values ranging from ~-40 to -80 G, and from ~-300 to -600 G, respectively. The discovery and confirmation of three new magnetic massive stars, including at least two He-weak stars, is an important contribution to one of MiMeS objectives: the understanding of the origin of magnetic fields in massive stars and their impact on stellar structure and evolution.

Based on observations collected at the European Southern Observatory, Chile (Program ID 187.D-0917).