Merge pull request #76 from followthesheep/master

added a new non-relativistic radial velocity module

starkit/base/operations/stellar.py

@@ -75,6 +75,9 @@ def evaluate(self, wavelength, flux, v_rot, limb_darkening):
         return wavelength, nd.convolve1d(flux, profile)
 
 class DopplerShift(StellarOperationModel):
+    '''
+    Module to model the velocity of the star with the relativistic redshift correction. 
+    '''
 
     operation_name = 'doppler'
 
@@ -90,6 +93,24 @@ def evaluate(self, wavelength, flux, vrad):
         doppler_factor = np.sqrt((1+beta) / (1-beta))
         return wavelength * doppler_factor, flux
 
+class RadialVelocity(StellarOperationModel):
+    '''
+    Module to model the classical definition of radial velocity
+    '''
+    operation_name = 'rv'
+
+    vrad = modeling.Parameter()
+
+    def __init__(self, vrad):
+        super(DopplerShift, self).__init__(vrad=vrad)
+        self.c_in_kms = const.c.to(u.km / u.s).value
+
+
+    def evaluate(self, wavelength, flux, vrad):
+        beta = vrad / self.c_in_kms
+        doppler_factor = (1.0 + beta)
+        return wavelength * doppler_factor, flux
+
 
 
 class CCM89Extinction(StellarOperationModel):
@@ -139,4 +160,4 @@ def __init__(self, distance, lum_density2cgs=1.):
     def evaluate(self, wavelength, flux, distance):
         conversion = self.lum_density2cgs / (4 * np.pi *
                                              (distance * self.pc2cm)**2)
-        return wavelength, flux * conversion
+        return wavelength, flux * conversion