A Study of Synthetic and Observed H_alpha Spectra of TT Hydrae

Abstract

The formation and properties of accretion discs and circumstellar material in Algol-type systems is not very well understood. In order to study the underlying physics of these structures, we have calculated synthetic Halpha spectra of TT Hya, which is an Algol-type eclipsing binary with an accretion disc. Both the primary and secondary stars were considered in the calculations as well as a disc surrounding the primary. The Roche model for the secondary star was assumed. The synthetic spectra cover all the phases including primary eclipse and are compared with the observed spectra. The influence of various effects and free parameters of the disc on the emerging spectrum was studied. This enabled us to put some constraints on the geometry, temperature, density and velocity fields within the disc. Differences found between the observed and synthetic spectra unravel the existence of a gas stream as well as a hotter disc-gas interaction region. An additional cooler circumstellar region between the C1 and C2 Roche surfaces is suggested to account for various observed effects. A new computer code called {\sc{shellspec}} was created for this purpose and is briefly described in this work as well. It is designed to solve simple radiative transfer along the line of sight in 3D moving media. The scattered light from a central object is taken into account assuming an optically thin environment. Output intensities are then integrated through the 2D projection surface of a 3D object. The assumptions of the code include LTE and optional known state quantities and velocity fields in 3D.

arXiv comment22 pages, 6 figures, last picture in color, accepted by ApJ

References in corpus (6)

• Detailed Mid- and Far-Ultraviolet Model Spectra for Accretion Disks in Cataclysmic Binaries
• Modeling the Spectral Signatures of Accretion Disk Winds: A New Monte Carlo Approach
• Resonance line-profile calculations based on hydrodynamical models of cataclysmic variable winds
• Ultraviolet Spectra of CV Accretion Disks with Non-Steady T(r) Laws
• Multicomponent radiatively driven stellar winds III. Radiative-acoustic waves in a two-component wind
• Radiative accelerations on Ne in the atmospheres of late B stars

Cited by in corpus (11)

• A simple model of the reflection effect for the interacting binaries and extrasolar planets
• Physical properties of the eclipsing Delta Sct star KIC 10661783
• Revealing the Nature of Algol Disks through Optical and UV Spectroscopy, Synthetic Spectra, and Tomography of TT Hydrae
• Optically thin circumstellar medium in $\beta$ Lyr A system
• Images of Gravitational and Magnetic Phenomena Derived from 2D Back-Projection Doppler Tomography of Interacting Binary Stars
• Modeling the Accretion Structure of AU Mon
• Looking into the cradle of the grave: J22564-5910, a young post-merger hot subdwarf?
• Occultations from an active accretion disk in a 72 day detached post-Algol system detected by K2
• An Accretion-Disc Model for the Algol-Type Eclipsing Binary System AV Del
• The Effect of the Circumstellar Material on the Light Curves of Eclipsing Binary Systems
• WISE J005128.08+645651.7: An enigmatic R Coronae Borealis star