HG12

class sbpy.photometry.HG12(H=8, G12=0.3, **kwargs)[source]

Bases: sbpy.photometry.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.

wfbQuantity, 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

G12

G12 parameter

H

H parameter

param_names

Methods Summary

evaluate(ph, h, g)

Evaluate the model on some input variables.

fit_deriv(ph, h, g)

Attributes Documentation

G12

G12 parameter

H

H parameter

param_names = ('H', 'G12')

Methods Documentation

static evaluate(ph, h, g)[source]

Evaluate the model on some input variables.

static fit_deriv(ph, h, g)[source]