After going to the exact product you have defined in your question.
It looks as though you may be viewing the LADDS 1 km band 6.
It states that the reflectance is determined for bands 1-19, 26 using the modis solar diffuser data modis data
In the product table the MOD 02 - Level-1B Calibrated Geolocation Data reflectance is determined Through knowledge of the solar irradiance (e.g., determined from MODIS solar-diffuser data, and from the target-illumination geometry).
The emissive library defines emissive values for different materials.
Free dictionary definition is ...
e·mis·sive adj. Having the power or tendency to emit matter or energy;
emitting.