Definition of "daystar"

Here dawn'd the daystar of Hesperia's fame, / Here herald glory first emblazed her name;

1809, Joel Barlow, The Columbiad, book VI, l. 245

And we have more sure the prophetic word; to which ye do well that ye take heed, as to a lamp shining in a dark place, until the day dawn, and the daystar arise in your hearts;

1865, Common English Version of the Bible, 2 Peter 1:19