Morning Star is a candlestick pattern. It consists of three candlestick, normally a strong bearish candle followed by small indecisive candle and then a strong bullish candle. The third day candle should be at least half of the first day's candle to have reliable Morning Star candle pattern. Morning Star is exactly opposite of Evening Star Candlestick pattern.
Morning Star is more reliable and most often found on bottom of the downtrend. It shows that on day one the sellers were dominating the session, on day two there was indecisiveness between buyers and sellers. And on day three buyers taking things under control and pulling the price up. Stop loss can be placed below the second day's low.