Bhagawān Vishnu's day falls on Thursday. The Sanskrit name for Thursday is Bṛhaspativāra: it is literally named after Jupiter.
Is the planet Bṛhaspati (Jupiter) related to Lord Vishnu?
The popular Navagraha Sukta, Grihya Sutras and Jaimini Sutras associate Vishnu and Narayana with Mercury. However, Lord Shiva himself, in the Jyotisharnava Navanitam, states that Narayana is related to Jupiter. Also in Lal Kitab there are some other correlations of Vishnu with the planets, with the Sun, as far as I remember.