How to get posts without author?

<?php
global $wpdb;
$ids = wp_list_pluck( $wpdb->get_results( "SELECT ID FROM {$wpdb->posts} WHERE post_type=post AND post_author=0" ), 'ID' );
$posts = get_posts( array( 'post__in' => $ids, 'posts_per_page' => -1 ) );