Bibcode
Ponti, G.; De, K.; Muñoz-Darias, T.; Stella, L.; Nandra, K.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 464, Issue 1, p.840-849
Fecha de publicación:
1
2017
Número de citas
26
Número de citas referidas
23
Descripción
The orbital period evolution of X-ray binaries provides fundamental
clues to understanding mechanisms of angular momentum transfer and loss
in these systems. We present an X-ray eclipse timing analysis of the
transient low-mass X-ray binary AX J1745.6-2901. This system shows full
eclipses and thus is one of the few objects of this class for which
accurate orbital evolution studies can be carried out. We report on
XMM-Newton and ASCA observations covering 30 complete X-ray eclipses
spanning an interval of more than 20 yr. We improve the determination of
the orbital period to a relative precision of 2 × 10-8,
two orders of magnitudes better than previous measurements. We
determine, for the first time, a highly significant rate of decrease of
the orbital period dot{P}_{orb}=-4.03± 0.32{×} 10^{-11} s
s-1. This is at least one order of magnitude larger than
expected from conservative mass transfer and angular momentum losses due
to gravitational waves and magnetic braking, and might result from
either non-conservative mass transfer or magnetic activity changing the
quadrupole moment of the companion star. Imprinted on the long-term
evolution of the orbit, we observe highly significant eclipse
leads-delays of ˜10-30 s, characterized by a clear state
dependence in which, on average, eclipses occur earlier during the hard
state.
Proyectos relacionados
Agujeros negros, estrellas de neutrones, enanas blancas y su entorno local
Los agujeros negros y estrellas de neutrones en binarias de rayos-X son laboratorios únicos para explorar la física de estos objetos compactos. No solo permiten confirmar la existencia de agujeros negros de origen estelar a través de mediciones dinámicas de sus masas, sino que también permiten investigar el comportamiento de la materia y la
Montserrat
Armas Padilla