The HR diagram was created by Ejnar Hertzsprung and Henry Norris Russell. They formed this chart in the early 1900's. They classified the stars by their temperature against their luminosity. The blue and the white stars are the hottest, and the red, orange, and yellow stars are the coolest. The stars are then classified by their size. Giants and Supergiants, Main Sequence, and dwarfs. Stars along the Main Sequence are the most common in size and temperature. The Sun, in which out Solar System rotates around, is found in the Main Sequence group of stars.
Commas always follow these clauses at the start of a sentence. If a dependent clause ends the sentence, however, it no longer requires a comma. Only use a comma to separate a dependent clause at the end of a sentence for added emphasis, usually when negation occurs. 3. Use commas to offset appositives from the rest of the sentence. Appositives act as synonyms for a juxtaposed word or phrase.
1. Use commas to separate independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, for, or, nor, so, yet. 2. Use commas after introductory a) clauses, b) phrases, or c) words that come before the main clause. 3. Use a pair of commas in the middle of a sentence to set off clauses, phrases, and words that are not essential to the meaning of the sentence. Use one comma before to indicate the beginning of the pause and one at the end to indicate the end of the pause.