We generate theoretical albedo and reflection spectra for a full range of extrasolar giant planet ( EGP ) models , from Jovian to 51-Pegasi class objects .
Our albedo modeling utilizes the latest atomic and molecular cross sections , Mie theory treatment of scattering and absorption by condensates , a variety of particle size distributions , and an extension of the Feautrier technique which allows for a general treatment of the scattering phase function .

We find that due to qualitative similarities in the compositions and spectra of objects within each of five broad effective temperature ranges , it is natural to establish five representative EGP albedo classes .
At low effective temperatures ( T _ { \textrm { eff } } \lesssim 150 K ) is a class of “ Jovian ” objects ( Class I ) with tropospheric ammonia clouds .
Somewhat warmer Class II , or “ water cloud , ” EGPs are primarily affected by condensed H _ { 2 } O. Gaseous methane absorption features are prevalent in both classes .
In the absence of non-equilibrium condensates in the upper atmosphere , and with sufficient H _ { 2 } O condensation , Class II objects are expected to have the highest visible albedos of any class .

When the upper atmosphere of an EGP is too hot for H _ { 2 } O to condense , radiation generally penetrates more deeply .
In these objects , designated Class III or “ clear ” due to a lack of condensation in the upper atmosphere , absorption lines of the alkali metals , sodium and potassium , lower the albedo significantly throughout the visible .
Furthermore , the near-infrared albedo is negligible , primarily due to strong CH _ { 4 } and H _ { 2 } O molecular absorption , and collision-induced absorption ( CIA ) by H _ { 2 } molecules .
In those EGPs with exceedingly small orbital distance ( “ roasters ” ) and 900 K \lesssim T _ { \textrm { eff } } \lesssim 1500 K ( Class IV ) , a tropospheric silicate layer is expected to exist .
In all but the hottest ( T _ { \textrm { eff } } \gtrsim 1500 K ) or lowest gravity roasters , the effect of this silicate layer is insignificant due to the very strong absorption by sodium and potassium atoms above the layer .
The resonance lines of sodium and potassium are expected to be salient features in the reflection spectra of these EGPs .
In the absence of non-equilibrium condensates , we find , in contrast to previous studies , that these Class IV roasters likely have the lowest visible and Bond albedos of any class , rivaling the lowest albedos of our solar system .
For the small fraction of roasters with T _ { \textrm { eff } } \gtrsim 1500 K and/or low surface gravity ( \lesssim 10 ^ { 3 } cm s ^ { -2 } ; Class V ) , the silicate layer is located very high in the atmosphere , reflecting much of the incident radiation before it can reach the absorbing alkali metals and molecular species .
Hence , the Class V roasters have much higher albedos than those of Class IV .

We derive Bond albedos ( A _ { B } ) and T _ { \textrm { eff } } estimates for the full set of known EGPs .
A broad range in both values is found , with T _ { \textrm { eff } } ranging from \sim 150 K to nearly 1600 K , and A _ { B } from \sim 0.02 to 0.8 .

We find that variations in particle size distributions and condensation fraction can have large quantitative , or even qualitative , effects on albedo spectra .
In general , less condensation , larger particle sizes , and wider size distributions result in lower albedos .
We explore the effects of non-equilibrium condensed products of photolysis above or within principal cloud decks .
As in Jupiter , such species can lower the UV/blue albedo substantially , even if present in relatively small mixing ratios .