gravity bubble on 2d planet

i want to make a 2d planet with gravity that extend to only a certain range. Similar to angry birds space.

the code for gravity is as follows:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Attractor : MonoBehaviour {
 
     private Rigidbody2D rigidBody;
     [SerializeField]
     private float G = -10;
     [SerializeField]
     public float bubbleRadius ;
     public static List<Attractor> attractors;
 
     public void OnEnable()
     {
         if (attractors == null)
             attractors = new List<Attractor>();
 
         attractors.Add(this);
         rigidBody = gameObject.GetComponent<Rigidbody2D>();
         rigidBody.gravityScale = 0;
     }
 
     public void OnDisable()
     {
         attractors.Remove(this);
     }
 
     public void FixedUpdate ()
     {
         foreach (Attractor attractor in attractors)
         {
             if(attractor != this )
                 this.Attract(attractor);
         }
     }
 
     public void Attract(Attractor other)
     {
        
         Rigidbody2D rigidBodyOther = other.rigidBody;
 
 
             Vector2 direction = this.rigidBody.position - rigidBodyOther.position;
             float distance = direction.magnitude;
 
             if (distance <= 0)
                 return;
             if(distance<=bubbleRadius)
         {
             float forceMagnitude = G * this.rigidBody.mass * rigidBodyOther.mass / (distance * distance);
             Vector2 force = forceMagnitude * direction;
 
             rigidBody.AddForce(force);
         }
             
         
           
         
         
     }
 }

this script is attached to both the planet and the rocket(rocket is supposed to be attracted only within the gravity bubble of the planet)