Bibcode
Long, Knox; Rodriguez-Gil, Pablo; Schmidtobreick, Linda; Gaensicke, Boris
Referencia bibliográfica
NOAO Proposal ID #2010A-0243
Fecha de publicación:
2
2010
Número de citas
2
Número de citas referidas
2
Descripción
SW Sextantis stars are fundamental to understanding how cataclysmic
variables evolve. Their maverick behavior and unexplained accumulation
in the orbital period range 3-4 h, about to enter the ``period gap''
where mass transfer is predicted to cease until a period of 2 h is
reached, challenge the current evolution theory. To characterize these
systems better, we need to determine the nature of the accreting white
dwarf and the more normal donor star. But they are usually invisible due
to the extreme accretion luminosity these systems normally show. The
only chances of characterizing the stars in the system are during rare
``low states'', when the mass transfer rate reaches a minimum for months
and the stars are exposed to observations and, therefore, binary
parameters measurement. Only dynamical mass measurements can address the
evolutionary status. This is a proposal to continue to monitor the
brightness of a select group of SW Sextantis stars begun when STScI was
a member of the SMARTS consortium to determine their long-term accretion
history and, to provide warning when they are entering faint states. The
data are essential to characterize the recurrence and duration of these
states (likely related to magnetic cycles in the donor star), and
trigger our TOO programs in 8-m class telescopes.