What is kelvin?(scientifically plz)

The kelvin is the base unit of temperature in the International System of Units,  It is named after the Belfast-born, Glasgow University engineer and physicist William Thomson.There are 100 degrees between the temperate at which water freezes at (273.16 K) and boils (373.16 K). Each unit on this scale, called a Kelvin rather than a degree, is equal to a degree on the Celsius scale. For this reason, just the K, not the degree symbol, is used when reporting temperatures in Kelvin.

Explanation:

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.