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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-4292
DTSTART:20160926T170000Z
DTEND:20160926T180000Z
DTSTAMP:20260305T102848Z
LAST-MODIFIED:20160922T143058Z
LOCATION:4421 Sterling
SUMMARY:Formation of low-mass helium white dwarfs orbiting millisecond
  pulsars \, Astronomy Lunch Talk\, Alina Istrate\, UW-Milwaukee
DESCRIPTION:Millisecond pulsars (MSPs) belong to a class of radio puls
 ars characterized by high rotational spin rates and low magnetic field
 s. These neutron stars are believed to be the end-product of binary ev
 olution\, i.e. the recycling scenario\, in which an old neutron star a
 ccretes matter and angular momentum from a close stellar companion for
  an extended period of time\, while being observable as an X-ray binar
 y.<br>
\n<br>
\nA handful of MSPs are  detected in very compact orbits
  (orbital periods between  2 − 9 hr)\,  around low-mass He WDs with 
 masses below 0.25 Msun and surface gravities 5 < log g < 7\, the so-ca
 lled extremely low-mass helium white dwarfs (ELM WDs).<br>
\n<br>
\nTo
 day we know of the existence of more than 80 ELM WDs\, with the majori
 ty of them in a binary system with a more massive CO WD. The increasin
 g number of discovered ELM WDs reveals that they are formed in differe
 nt environments\, from the Galactic disk to open and globular clusters
 . ELM WDs are most likely the result of binary evolution as they canno
 t be formed from single stars within a Hubble time. The new wealth of 
 data raises questions regarding the puzzling presence of metals in the
  atmospheres of young bloated ELM proto-WDs and the newly discovered p
 ulsations in three ELM proto-WDs.  The current available evolutionary 
 models fail to explain such properties. <br>
\nIn this talk\, I will p
 resent the latest theoretical efforts  regarding the formation and evo
 lution of ELM WDs.  
URL:https://www.physics.wisc.edu/events/?id=4292
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