 |
| Titel |
Modelling Line Emission from T Tauri Binaries |
| VerfasserIn |
Miguel de Val-Borro, Gösta Gahm, Eric Stempels, Adam Peplinski |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250055680
|
|
|
|
|
|
| Zusammenfassung |
| Young close binaries open central gaps in the surrounding circumbinary
accretion disk, but the stellar components may still gain mass from gas
crossing through the gap. It is not well understood how this process operates
and how the stellar components are affected by such inflows. Our main goal is
to investigate how gas accretion takes place and evolves in close T Tauri
binary systems. In particular, we model the accretion flows around two close T
Tauri binaries, V4046 Sgr and DQ Tau, both showing periodic changes in emission
lines, although their orbital characteristics are very different. In order to
derive the density and velocity maps of the circumbinary material, we employ
2-D hydrodynamic simulations with a locally isothermal equation of state. From
the derived density distribution, and assuming that the gas is optically thin
in the higher Balmer lines, we derive expected line profiles for the case of
V4046 Sgr. The profiles are compared to spectroscopic observations of the
V4046 Sgr system, which are known to vary strongly with phase. Our simulations
indicate that significant non-axisymmetric gas flows are generated in close T
Tauri binary systems that become quasi stable after a few orbits. Gas flows
across the circumbinary gap through the co-rotating Lagrangian points, and
local circumstellar disks develop around both components. Non-axisymmetric gas
flows are generated inside the inner gap in close binary systems on circular
and eccentric orbits. Mass is preferentially channelled towards the primary
and its circumstellar disk is more massive than the disk around the secondary.
The line profile variability tracing the gas flows in the central cavity shows
clear similarities with the corresponding observed line profile variability in
V4046 Sgr, when the local circumstellar disks emission was excluded. Closer to
the stars magnetospheric accretion may dominate while further out the dynamic
accretion process outlined here dominates. |
|
|
|
|
|
|