After self-immolation, when Goddess Sati took birth as the daughter of Lord Himalaya, she came to be known as Shailputri, which means the daughter of mountain. The Goddess governs moon and is worshipped on the first day of Navratri.
The unmarried avatar of Goddess Parvati is worshipped as Goddess Brahmacharini. She governs the planet of Mangal and is worshipped on the second day of Navratri.
Goddess Chandraghanta adorns half chandra (Moon) on her forehead which resembles bell, hence she got the name Chandraghanta. She is worshipped on third day of Navrati.
Goddess Kushmanda, who is worshipped on the fourth day of Navratri is believed to have lived at the center of the sun.She was the one who drove away the darkness and created the three divine goddesses and other gods as well.
Goddess Skandamata mounts on a lion and carries Lord Skanda, also known as Kartikeya on her lap. She has four arms and governs the planet Budha (Mercury). She is worshipped on fifth day.
When Goddess Parvati decided to destroy the demon Mahishasura, she took the form of Goddess Katyayani. Hence, this avatar of the devi is also known as the warrior goddess.She is worshipped on sixth day.
To kill Shumbha and Nishumbha, Goddess Parvati removed her outer skin and hence came to be known as Goddess Kalaratri. She is the most fearsome avatar of Goddess Parvati and is worshipped on seventh day.
At the age of sixteen, Goddess Shailputri's complexion was extremely fair, hence she came to be known as Goddess Mahagauri. She governs planet Rahu and is worshipped on the eighth day of Navratri.
Worshipped on the ninth day of Navratri, Goddess Siddhidatri sits on lotus flower and rides on a lion. Folks say that when Goddess Siddhidatri appeared from the left half of Lord Shiva, he came to be known as Ardhanarishwara.