Judge ES swears EDPY married JS on May 4, 1843, a Thursday (frequently associated with Jupiter).
Emily Dow Partridge Young affidavit, MS 3423, Church History Library
Territory of Utah} County of Salt Lake} SS. Be it remembered that on this first day of May A.D. 1869, personally appeared before me, Elias Smith Probate Judge for said county, Emily Dow Partridge Young, who was by me sworn in due form of law and upon her oath saith, that on the fourth day of March A.D. 1843 at the City of Nauvoo, County of Hancock State of Illinois, she was married or sealed to Joseph Smith, President of the Church of Jesus Christ of Latter Day Saints by Heber C. Kimball, one of the Twelve Apostles of said Church, according to the laws of the same regulating marriage, in the presence of Emily D. P. Young Subscribed and sworn to by the } said Emily D. P. Young, the day } and year first above written, } E. Smith Probate Judge