Date of upload:
14.07.2016
Co-author:
M. Aurière, S. Deheuvels, R. A. García, F. Lignières, S. Mathur, P. Petit
Abstract:
Spectropolarimetric measurements allow us to detect and measure magnetic field through Zeeman effect in stellar photospheres. We observed with the spectropolarimeters Narval (at Telescope Bernard Lyot) and ESPADONS (at CFHT) a few Kepler Red Giants in 2012 and 2013, especially four stars showing depressed dipolar modes. Interestingly, recent seismic studies by Fuller et al. (2015) suggest these stars had a magnetic history. After presenting shortly the technique, I will detail the detections we did and the constraints we put in surface magnetic fields, then I will discuss the origin of these fields by comparing these observations to a broader sample of red giants observed by Aurière et al. (2015).
