Transform.RotateAround

Description

Rotates the transform about axis passing through point in world coordinates by angle degrees.

This modifies both the position and the rotation of the transform.

using UnityEngine;

//Attach this script to a GameObject to rotate around the target position.
public class Example : MonoBehaviour
{
    private Vector3 target = new Vector3(5.0f, 0.0f, 0.0f);

    void Update()
    {
        // Spin the object around the world origin at 20 degrees/second.
        transform.RotateAround(target, Vector3.up, 30 * Time.deltaTime);
    }
}