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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:20240319T075307Z
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.
\n
\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).
\n
\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.
\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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