antaress.ANTARESS_grids.ANTARESS_star_grid module

calc_RVrot(x_st_sky, y_st, istar_rad, veq, alpha_rot, beta_rot)

Stellar rotational rv

Calculates radial velocity of stellar surface element from rotation (in km/s). The absolute and radial velocity depend on stellar latitude in presence of differential rotation.

\[\begin{split}v &= \Omega R_\mathrm{\star} \\ &= \Omega_\mathrm{eq} (1-\alpha_\mathrm{rot} y_\mathrm{lat}^2 - \beta_\mathrm{rot} y_\mathrm{lat}^4) R_\mathrm{\star} \\ &= v_\mathrm{eq} (1-\alpha_\mathrm{rot} y_\mathrm{lat}^2 - \beta_\mathrm{rot} y_\mathrm{lat}^4)\end{split}\]

The velocity vector in the star frame is defined as

\[\begin{split}v_\mathrm{x,star} &= v \cos(\Phi) \\ v_\mathrm{y,star} &= -v \sin(\Phi) \\ v_\mathrm{z,star} &= 0\end{split}\]

Where \(\Phi\) is the angle between the LOS z and the surface element in the zx plane. The velocity vector in the inclined star frame is then

\[\begin{split}v_\mathrm{x,sky star} &= v \cos(\Phi) \\ v_\mathrm{y,sky star} &= -v \sin(\Phi) cos(i_\star) \\ v_\mathrm{z,sky star} &= -v \sin(\Phi) sin(i_\star)\end{split}\]

And the radial velocity along the \(z_\mathrm{sky star}\) axis, defined as negative toward the observer, is then

\[\begin{split}rv &= - v_\mathrm{z,sky star} \\ &= v \sin(\Phi) sin(i_\star) \\ &= v x_\mathrm{norm} sin(i_\star) \\ &= x_\mathrm{norm} v_\mathrm{eq} sin(i_\star) (1-\alpha_\mathrm{rot} y_\mathrm{lat}^2 - \beta_\mathrm{rot} y_\mathrm{lat}^4)\end{split}\]

Parameters:

TBD

Returns:

TBD

calc_CB_RV(ld_coeff, LD_mod, c1_CB, c2_CB, c3_CB, f_GD)

Stellar convective blueshift

Calculates radial velocity of stellar surface element from convective blueshift.

Parameters:

TBD

Returns:

TBD

calc_GD(x_grid_star, y_grid_star, z_grid_star, star_params_eff, gd_band, x_st_sky_grid, y_st_sky_grid)

Gravity-darkening intensity

Calculates blackbody emission with gravity-darkening, using the formalism from Barnes+2009. It accounts from gravity-darkening through temperature variation and local blackbody emission.

Parameters:

• TBD

• star_params_eff (dict) – dictionary containing nominal or variable (overwritten from fit routines) stellar properties

Returns:

TBD

get_LD_coeff(transit_prop, iband)

Limb-Darkening coefficients

Store input limb-darkening coefficients in common structure [LD_u1,LD_u2,LD_u3,LD_u4].

Parameters:

• transit_prop (dict) – dictionary containing the planet/active region limb-darkening properties.

• iband (int) – index of the band considered.

Returns:

ld_coeff (list) – formatted list of the limb-darkening coefficients used.

calc_LD(LD_mod, mu, ld_coeff)

Limb-Darkening intensity

Calculates limb-Darkening value at a given \(\mu\) (from 1 at stellar center to 0 at the limb).

Parameters:

TBD

Returns:

TBD

calc_Isurf_grid(iband_list, ngrid_star, system_prop, coord_grid, star_params, Ssub_Sstar, Istar_norm=None, region='star', Ssub_Sstar_ref=None)

Stellar intensity grid.

Calculates flux and intensity values over the stellar grid, from various contributions.

Parameters:

TBD

Returns:

TBD

calc_st_sky(coord_grid, star_params)

Sky-projected stellar grid.

Calculates coordinates of stellar cells in the sky-projected star rest frame.

Parameters:

TBD

Returns:

TBD

model_star(mode, grid_dic_eff, grid_type, system_prop_eff, nsub_Dstar, star_params_eff, var_stargrid_bulk, var_stargrid_I)

Model stellar grid

Defines coordinates and intensity values over the stellar grid.

Parameters:

TBD

Returns:

TBD

up_model_star(args, param_in, star_params_in, system_prop_in, grid_dic_in)

Update stellar grid

Updates bulk stellar properties, as well as coordinates and intensity values over the stellar grid. This function is called when stellar properties differ from the nominal ones, eg during a fitted step. Outputs will be used to overwrite fields within args[‘system_param’], args[‘system_prop’], args[‘grid’]

Parameters:

TBD

Returns:

TBD