Q:

How long was the Little Prince on Earth?

In The Little Prince, the titular little prince lands on Earth. 
How long was he there?  
If I recall correctly, the prince left on the 8th day of the pilot being lost in the desert. I don't know if the prince landed the same time the pilot crashed. Did he? 
How long was the prince on Earth?

A:

One Year.
Near the end, the Little Prince journeys to the wall and has an encounter with a snake - the same snake, I believe, that he met when he first arrived on Earth. He wants to meet death by its venom. The narrator saves him, and after some brief discussion, the prince looks up at "his star":

But he said to me:
"Tonight, it will be a year . . . My star, then, can be found right above the place where I came to the Earth, a year ago . . .

After a short conversation, the prince lets the snake bite him, and dies.
I'm not totally certain what the Little Prince means by "my star". I've considered that it could be the asteroid that the narrator believes is asteroid B-612 - and that may be correct, as he tells the snake when he arrives on Earth that he can see "his planet". I don't, however, have anything to back this up.

The French text is

Mais il me dit:
Cette nuit, ça fera un an. Mon étoile se trouvera juste au-dessus de l'endroit où je suis tombé l'année dernière...

