The green background and the yellow diamond stand for the Royal House of Braganca and the Royal House of Habsburg.
The myriad of stars is a reminder of the day that Brazil became the Republic of Brazil. The date was November 15, 1889 and the stars on the flag were designed in honor of the night sky over the city of Rio de Janeiro on that date.
There are 27 stars in all. The stars beneath the white banner stand for each of the 26 Brazilian states. The single star above the white banner represents the Federal District. When a new state is established, the flag is redesigned to reflect the change.