Regex - basic string replacement [closed]

I have a string which may or may not contain a code for an emote, all of which begin the same: "auroraa1"

Such as:
"auroraa1Smile", "auroraa1Bye", "auroraa1Love"

I need to be able to grab the whole code for a given emote without any of the spaces before/after and alter it.

In a sentence such as:

"Hello Aurora! auroraa1Smile  How are you?"

I need to alter it to:

"Hello Aurora! [emote:4771491:auroraangel79Smile] How are you?"

Question:

How can I create a regex to capture the emote code from the source string: auroraa1Hi

My current code:

//read the twitchMsg and look for "auroraa1" which denotes an emote            string wordToFind = "auroraa1";            
string kickMsg = "NONE";            
kickMsg = CPH.GetGlobalVar<string>("s_msg");

// Find all occurrences of the wordToFind as a whole word            MatchCollection matches = Regex.Matches(kickMsg, $@"{wordToFind}", RegexOptions.IgnoreCase);

if (matches.Count > 0)            
{                
    CPH.SendMessage($"'{wordToFind}' found {matches.Count} times as a whole word.");                
    foreach (Match match in matches)                
    {                    
        CPH.SendMessage($"Found at index: {match.Index}");
    }            
}            
else
{                
    CPH.SendMessage($"'{wordToFind}' not found as a whole word.");            
}            

return true;

Here's the ouput I am getting:

'auroraa1' found 1 times as a whole word.  
Found at index: 28

I need output to say that it found 'auroraa1Smile'