Artículo de revista
Precession and accretion in circumbinary discs: the case of HD 104237
Fecha
2015Registro en:
MNRAS 448, 3545–3554 (2015)
0035-8711
DOI: 10.1093/mnras/stv284
Autor
Dunhill, A. C.
Cuadra, J.
Dougados, Catherine
Institución
Resumen
We present the results of smoothed particle hydrodynamics (SPH) simulations of the disc
around the young, eccentric stellar binary HD 104237. We find that the binary clears out a
large cavity in the disc, driving a significant eccentricity at the cavity edge. This then precesses
around the binary at a rate of ˙ = 0. ◦ 48T
−1
b , which for HD 104237 corresponds to a precession
period of 40 years.We find that the accretion pattern into the cavity and on to the binary changes
with this precession, resulting in a periodic accretion variability driven purely by the physical
parameters of the binary and its orbit. For each star we find that this results in order of
magnitude changes in the accretion rate. We also find that the accretion variability allows
the primary to accrete gas at a higher rate than the secondary for approximately half of each
precession period. Using a large number of three-body integrations of test particles orbiting
different binaries, we find good agreement between the precession rate of a test particle and
our SPH disc precession. These rates also agree very well with the precession rates predicted
by the analytic theory of Leung & Lee, showing that their prescription can be accurately used
to predict long-term accretion variability time-scales for eccentric binaries accreting from a
disc. We discuss the implications of our result, and suggest that this process provides a viable
way of preserving unequal-mass ratios in accreting eccentric binaries in both the stellar and
supermassive black hole regimes.