Collision Won't Work

I am trying to spawn child objects and have them kill the player when they collide. I used the function from the unity website and it still will not work. Any ideas why?

 using UnityEngine;
 using System.Collections;
 using System;
 
 public class Player : MonoBehaviour
 {
     public GameObject player;
     public GameObject astroid;
     public int fallBoundary = -10;
 
  
     void OnCollisionEnter2D(Collision2D coll)
     {
         if (coll.gameObject.tag == "astroid")
         {
             GameObject.Destroy(player);
         }
       
     }
 
 }