In ancient times, this star rose at dawn during the hottest time of summer, thus the "dog days of summer"
In August 1609 he demonstrated his newly constructed telescope to the senate of Venice, who then doubled his salary
Add this letter to Mars & you get a fen
Add this letter to Earth & you get a scarcity
Add this letter to Jupiter's moon Io & you get an acronym that's a ground-floor stock offer for regular guys
Add this letter to Saturn's moon Titan & you get a Renaissance guy who liked to paint Venus
Add this letter to star & get something harsh or grim