Program SHELLSPEC is designed to calculate lightcurves, spectra and images of interacting binaries and extrasolar planets immersed in a moving circumstellar environment which is optically thin. It solves simple radiative transfer along the line of sight in moving media. The assumptions include LTE and optional known state quantities and velocity fields in 3D. Optional (non)transparent objects such as a spot, disc, stream, jet, shell or stars as well as an empty space may be defined (embedded) in 3D and their composite synthetic spectrum calculated. Roche model can be used as a boundary condition for the radiative tranfer. The program does not solve the inverse problem of finding the stellar and orbital parameters and the user is referred to other well known codes which can handle this problem more effectively e.g.: WD2007 which is a recent version of the Wilson-Devinney code modified by Gene Milone and Josef Kallrath.
The main applications are probably in the field of interacting binaries, cataclysmic variable stars, Algol-type eclipsing binaries, and extrasolar planets but the code is a flexible tool which can be used to study a large variety of objects and effects. A more detailed description of the code is in Budaj and Richards (2004) and in the user manuals. Examples of the possible applications can be found in Budaj et al. (2005), Miller et al. (2007). Output of widely used programs for stellar atmosphere synthetic spectra, SYNSPEC (Hubeny, Lanz and Jeffery, 1994), can be used as an input. The latest version of the code which has a new model of the reflection effect is available with complete documentation and example runs here: DOWNLOAD SHELLSPEC17.
A separate code which calculates the Roche surface and surface temperature distribution according to the new reflection effect can be found with the complete documentation and examples here: DOWNLOAD ROCHE.
Below is the schematic illustration of the new model of the reflection effect
(Budaj 2011)
which consist of reflection, heating and heat redistribution.
It is a pole-on view of the planet irradiated by the star. Red regions on
the day side are hot while yellow regions on the night side and around
poles are cool due to the irradiation and zonal heat transfer.
$\delta$ is irradiating angle,
$A_{B}$ is Bond albedo, $P_{r}$ is heat redistribution parameter,
$T_{ir}$ is temperature associated with local heating, $T_{dn}$ is
associated with heat redistribution and depends on the latitude,
and $T_{old}$ is associated with interior cooling and with surface
temperatures in the absence of the irradiation.
Roche shape of the planet corresponds to the filling factor equal to 1.
Position and size of the star are not to scale.
Below is the demonstration of an artificial test model and an artificial spectral line. The model includes two stars, a Keplerian equatorial disc around a bigger primary, a slightly inclined jet and a slowly expanding shell surrounding the system. Stars are treated as blackbodies, the primary is a sphere with limb darkening imposed on while the secondary fills its Roche lobe and is subject to gravity darkening only. The centers of the jets and shell have no net space velocity while the net velocity of the center of the disc corresponds to that of the primary. Jets precess with the orbital period. For the sole purpose of this illustration, the input values were manipulated so that a contribution from each object could be seen.
