Massive-star magnetospheres in the near infrared

Séminaire IPAG de Mary Oksala (LESIA), jeudi 17 mars 2016 à 11h00, IPAG seminar room

Currently, the main tool for studying the magnetic fields and magnetospheres of hot, early-type stars is optical spectra. The signatures of magnetospheres appear as emission features in the Balmer series, typically only strongly visible in the Halpha line. Recently, we have begun to explore magnetospheres via infrared spectroscopy. Infrared spectroscopic evidence of magnetospheric material has several advantages over optical in that there are many more hydrogen lines to study, the detection is much more obvious due to a lower stellar flux contribution, and the features probe deeper within the magnetosphere, revealing more complex structure. By examining both optical and infrared features together, we can learn more about the confinement of the material by the magnetic field. Furthermore, by understanding how magnetic signatures appear in infrared spectra, we can develop a strategy to utilize the capabilities of future high-resolution infrared spectropolarimeters, such as CRIRES+@VLT and SPIRou@CFHT to study magnetic stars inaccessible in the optical.