This is not a regular star like other 27 stars of horoscope. You can all it as invisible star. The Moon has 27 wives; they are the daughters of Daksha Prajapathi and wife Panchajani (Virani). These 27 sisters had one brother and that brother is Abhijit Nakshatra. Abhijit Nakshatra begins from the last quarter of Uttarashada and ends at the first 1/15th segment of Shravana. Abhijit is the Sanskrit name for Vega, the brightest star in the northern constellation of Lyra.
The only time Abhijit is used is for Muhurta. Abhijit (Lorded by Mahavishnu) indicates the direction in which the Sun (i.e. solar system) is processing in the universe and in Krishna marga Abhijit Nakshatra faces west. . Hence, it represents the eye. (Chakshyur) of the zodiac. Aratus,
Abhijit means “Victorious” or “the one who cannot be defeated”. In Bhagavad Geeta, Krishna said that He was Shiva among Rudras; He was Arjuna among Pandava and He was Abhijit among Nakshatra Classical Vedic texts mention Abhijit as one of the most auspicious time for doing any auspicious activity excepting travelling to southern direction. Its deity is Lord Brahma. Some Vedic texts also mention that 28 minutes before and 28 minutes after 12:00 clock (a.m. and p.m. both) is called as Abhijit Muhurtah too.
The story from Mahabaratha. Pandu is the king of Hastinapur. Kunthi & Madhri are wifes of the King Pandu. Madhri blessed with the help of Ashwini Kumaras blessed with Nakula & Sahadev. Among them Nakula is great horse rider another Sahadeva is great astrologer.
The opponents of padavas king duryodhan approached sahadeva for taking good muhurtha to win the kurukshetra war. Even he is enemy being a good astrologer given the great Abhijith muhurtha to win the war.
Lord Krishna understand this situation. Created a magic clouds to manipulate the muhurtha time to confuse the king duryodhan. Simply duryodhan trapped into it.
Now we can understand how powerful it is.