HG12¶
- class sbpy.photometry.HG12(H=8, G12=0.3, **kwargs)[source]¶
Bases:
HG12BaseClass
HG12 photometric phase model (Muinonen et al. 2010)
This system is adopted by IAU as the “standard” model for disk-integrated phase functions of planetary objects. Note that there is a discontinuity in the derivative for parameter G12, sometimes making the model fitting difficult. Penttil”a et al. (2016, Planet. Space Sci. 123, 117-125) revised the H, G12 system such that the G12 parameter has a continuous derivative. The revised model is implemented in class
G12_Pen16
.Examples
>>> # Define the phase function for Themis with >>> # H = 7.121, G12 = 0.68 >>> >>> import astropy.units as u >>> from sbpy.calib import solar_fluxd >>> from sbpy.photometry import HG12 >>> themis = HG12(7.121 * u.mag, 0.68, radius = 100 * u.km, wfb = 'V') >>> with solar_fluxd.set({'V': -26.77 * u.mag}): ... print('geometric albedo = {0:.4f}'.format(themis.geomalb)) ... print('phase integral = {0:.4f}'.format(themis.phaseint)) geometric albedo = 0.0622 phase integral = 0.3949
Initialize DiskIntegratedPhaseFunc
- Parameters:
- radiusastropy.units.Quantity, optional
Radius of object. Required if conversion between magnitude and reflectance is involved.
- wfb
Quantity
,SpectralElement
, string Wavelengths, frequencies, or bandpasses. Bandpasses may be a filter name (string). Required if conversion between magnitude and reflectance is involved.
- **kwargsoptional parameters accepted by
astropy.modeling.Model.__init__()
Attributes Summary
Names of the parameters that describe models of this type.
Methods Summary
evaluate
(ph, h, g12)Evaluate the model on some input variables.
fit_deriv
(ph, h, g12)Attributes Documentation
- G12 = Parameter('G12', value=0.3)¶
- H = Parameter('H', value=8.0)¶
- param_names = ('H', 'G12')¶
Names of the parameters that describe models of this type.
The parameters in this tuple are in the same order they should be passed in when initializing a model of a specific type. Some types of models, such as polynomial models, have a different number of parameters depending on some other property of the model, such as the degree.
When defining a custom model class the value of this attribute is automatically set by the
Parameter
attributes defined in the class body.
Methods Documentation