JQuery find partial match within an element

I have a dynamic elements as follows

<div class="pax_details">
  <div class="adult_pax">
    <input name="first_name_1">
    <input name="last_name_1">
  </div>
  <div class="adult_pax">
    <input name="first_name_2">
    <input name="last_name_2">
  </div>
</div>
<div class="pax_details">
  <div class="adult_pax">
    <input name="first_name_3">
    <input name="last_name_3">
  </div>
  <div class="adult_pax">
    <input name="first_name_4">
    <input name="last_name_4">
  </div>
</div>

I need to fetch all adults first name and last name into an array of objects using jquery
like

[[{"first_name":"Anish","last_name":"gopi"},{"first_name":"Vinay","last_name":"prasad"}]
[{"first_name":"Ananaya","last_name":"vital"},{"first_name":"Guru","last_name":"govind"}]]

What I tried so far?

let i = 0;
$('.pax_details').each(function(index,item){
    $(item).find('.adult_pax').each(function(index,adult){
        alert($(adult).find('input[name^="first_name_"]').val());
    });
    i++;
});