# Hapke parameters

The Hapke parameters are a set of parameters for a quasi-experimental model that are commonly used to describe the
directional reflectance properties of the airless regolith surfaces of bodies in the solar system. They were developed by astronomer Bruce Hapke at the University of Pittsburgh.

The quantities are cite journal | author= P. Helfenstein "et al"| title= "Galileo Photometry of Asteroid 243 Ida"| journal= Icarus| year= 1996| volume= 120| pages= 48| url= http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1996Icar..120...48H&amp;db_key=AST&amp;data_type=HTML&amp;format=&amp;high=444b66a47d10703| doi= 10.1006/icar.1996.0036] :

# — Single scattering albedo. This is the ratio of scattering efficiency to total light extinction (which includes also absorption), for small-particle scattering of light. That is, $K_s/\left(K_s+K_a\right)$, where $K_s$ is the scattering coefficient, and $K_a$ is the absorption coefficient [http://scienceworld.wolfram.com/physics/SingleScatteringAlbedo.html Single Scattering Albedo] , scienceworld.wolfram.com.]
#$h$ — The width of the opposition surge.
#$B_0$ or $S_0$ — The strength of the opposition surge.
#$P_0$ or "g" — The particle phase function parameter, also called the asymmetry factor.
#$heta$ — The effective surface tilt, also called the macroscopic roughness angle.

The Hapke parameters can be used to derive other albedo and scattering properties such as the geometric albedo, the phase integral, and the Bond albedo.

ee also

*albedo
*Geometric albedo
*Bidirectional reflectance distribution function

References

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• Opposition surge — The opposition effect brightens the area around Buzz Aldrin s shadow due to retroreflective properties of lunar regolith. The opposition surge (sometimes known as the opposition effect, opposition spike or Seeliger effect[1]) is the brig …   Wikipedia

• Albedo — The albedo of an object is the extent to which it diffusely reflects light from the sun. It is therefore a more specific form of the term reflectivity. Albedo is defined asthe ratio of diffusely reflected to incident electromagnetic radiation. It …   Wikipedia

• Photometry (astronomy) — Photometry is a technique of astronomy concerned with measuring the flux , or intensity of an astronomical object s electromagnetic radiation. Usually, photometry refers to measurement over large wavelength bands of radiation; but, when not only… …   Wikipedia

• Opposition effect — The opposition effect (also opposition spike, or opposition surge) is the brightening of a rough surface, or an object with many particles, when illuminated from directly behind the observer. It is so named because the reflected light from the… …   Wikipedia

• Geometric albedo — The geometric albedo of an astronomical body is the ratio of its actual brightness at zero phase angle (i.e. as seen from the light source) to that of an idealized flat, fully reflecting, diffusively scattering (Lambertian) disk with the same… …   Wikipedia

• Asteroid belt — For the album by Velvet Chain, see Asteroid Belt (album). The asteroid belt (shown in white) is located between the orbits of Mars and Jupiter. The asteroid belt is the region of the Solar System located roughly between the orbits of the planets… …   Wikipedia

### Share the article and excerpts

Do a right-click on the link above