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PRODID:https://murmitoyen.com/events/vanille/udem/
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UID:69dc17a22005f
DTSTAMP:20260412T180730
DTSTART:20170126T113000
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DTEND:20170126T123000
URL:https://murmitoyen.com/events/vanille/udem/detail/739743-the-strange-ma
 gnetic-fields-of-white-dwarf-stars-john-landstreet-university-of-western-o
 ntario
LOCATION:Pavillon Roger-Gaudry \, 2900\, boul. Édouard-Montpetit\, Local M
 -415\, Montréal\, QC\, Canada
SUMMARY:The strange magnetic fields of white dwarf stars - John Landstreet 
 - University of Western Ontario
DESCRIPTION:The strange magnetic fields of white dwarf stars
Résumé
We ha
 ve observational detections of magnetic fields in at least some stars of t
 he major stages of stellar evolution\, from the pre-main sequence to the c
 ommonest stellar final state\, the white dwarfs. However\, the evolution o
 f a field as a star evolves from one stage to another is still hardly unde
 rstood. The white dwarfs are particularly puzzling. Naively\, their fairly
  rare megaGauss magnetic fields could be the descendents\, by flux conserv
 ation\, of the fairly rare kiloGauss magnetic fields of upper main sequenc
 e stars. But how these main sequence fields survive the giant and AGB stag
 es of stellar evolution\, or how 'new' fields are produced in some young w
 hite dwarfs (perhaps by binary merger events) is still far from clear. The
 oretical advances depend on a good foundation of observations to test and 
 refine models. I have been working with Stefano Bagnulo and Gena Valyavin 
 to provide a systematic observational description of the occurrence and fi
 eld geometry of magnetic white dwarfs close to the weak field limit of the
  very broad observed field strength distribution. In the course of this wo
 rk\, we have developed a powerful method of using ESPaDOnS on the CFHT to 
 detect and ultimately model very weak white dwarf fields. This talk will s
 urvey some of our interesting first results on the kiloGauss stars WD2047+
 372 and WD2359-434\, and on non-magnetic 40 Eri B.
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