custom post types – How to specify user ID for a CPT wp_insert_post when there’s no actual user (it’s programmatic)

Here’s what I hope is a simple question. When using wp_insert_post to add a custom post type record, if the post author isn’t an actual editorial user, but instead an externally-driven data item (in my case, a log entry), how should the post_author field be specified? Do I just pick a user ID, leave it blank, or set it to something like 1? Thanks!