Editing header.php for a child theme

Hello. I’m trying to add the below to my Material Gaze theme, to force IE to use IE9 standards, as anything below that causes the page to render incorrectly.

<meta http-equiv=”X-UA-Compatible” content=”IE=EmulateIE9″>

However, as this needs to be added to header.php, how can I add this to the Material Gaze theme, which is a child theme of the Stargazer theme, when the child theme doesn’t have a header.php file to be edited? The child theme only seems to have the functions.php file available for editing from within WordPress.

Many thanks.