In Hinduism, every day is dedicated to a specific god in the Hindu pantheon. Thursday, which is Brihaspatiwar or Vrihaspativar, is specially dedicated to Lord Vishnu and Brihaspati, the Guru of Devas. Yellow is the color of the day.
Thursdays are considered to be the best days for the worship of Jupiter.Worship of this Devata results in a cure from ailments affecting the stomach and helps one to ward off his sins, helps him in gaining strength, valour, longevity etc. He grants the boon of father-hood to the childless, good education.
In the zodiac, He is the Lord of Dhanus and Meena. Guru stays for one year in each. Rasi, taking 12 years to complete the cycle.
Bṛhaspati attained the position of Guru of the Devas by performing penances on the banks of Prabhas Tirtha. Lord Shiva granted him this position, as well as his position as one of the Navagrahas (Nine Planets).
In the BhagavadGeeta, Shree Krishna says “I am Brihaspati among the priests”.
In later times, Brihaspati was identified with the planet of the same name, equated with Jupiter. He is thus one of the NAVAGRAHA or nine planets and is represented in temples on Navagraha panels. The AGNI PURANA states that his images should be adorned with a necklace of Rudraksha beads. Brihaspati’s chariot is called Nitighosha and is drawn by eight pale horses. In early releifs, Brihaspati was two-handed, sometimes holding a rosary and a water pot. In modern temples and art, he is depicted dressed in yellow and seated on lotus, or in his chariot. He has 4 arms and holds a mace, a rosary and a sphere or water-pot.
Brihaspati is the son of Rishi Angiras (according to the Rig Veda 4.40.1) and Surupa according to the Shiva Purana. He has two brothers named Utathya and Samvartana, and has three wives. His first wife, Shuba, gave birth to Bhanumati, Raaka, Archishmati, Mahamati, Mahishmati, Sinivali, and Havishmati. His seven daughters. His second wife, Tara, gave birth to seven sons and a daughter. Through Bṛahspati’s third wife, Mamata, he had two sons, Kacha and Bharadwaja.Tara, who was later fell in love with Chandra, the moon and Budha (Mercury) was born to them.
After the war between Brihaspati and Chandra, Tara returned to her husband. Brihaspati’s another son Kacha was assigned to learn the Sanjivani mantra from Shukracharya, the guru of asuras. The mantra could bring back life in a dead and hence gods sent Kacha to learn it. There as a student, Shukracharya’s daughter Devayani,fell in love with Kacha.
Brihaspati is also noted to have taught asuras for ten years impersonating as Shukracharya. He is the designated “Vyasa of the fourth Dwapara” age.