syntax error, unexpected '​' (T_STRING), expecting function (T_FUNCTION) or const (T_CONST) Laravel

I have a shop model you can see it

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use TCG\Voyager\Traits\Spatial;


class Shop extends Model
{
    use Spatial;

​   protected $spatial = ['lat'];
}

but it consistently giving me error after writing these lines of code

syntax error, unexpected '​' (T_STRING), expecting function (T_FUNCTION) or const (T_CONST)

via Chebli Mohamed