US divisional casualties?

It's a little star put on the service ribbon to indicate he did more than one tour of service that made him eligible for the original ribbon. I have a Vietnam service ribbon with two stars, denoting three years in country. (Didn't finish the third one but I got another star on my purple one to make three.)

 

You also see the stars referred to in two other ways:

1. As the Bronze Star Medal, which is a medal for valor or service by that name and has a red, blue and white ribbon associated with. If it is a BSM for bravery, it will have a V device (for valor) attached to the ribbon, like the stars being asked about in the thread.

2. A bronze star device, which, like the V device above, denotes additional information about the ribbon or medal to which it is attached. As indicated above, it can be attached to campaign medals, such as the European-African-Middle Eastern campaign medal to denotes the various campaigns the recipient was involved in. In lieu of 5 bronze star devices on a single campaign ribbon, a silver star device (as opposed to the Silver Star Medal) is attached to denote the 5 campaigns. While rare, it is possible for an individual to have participated in 6 or more campaigns and would wear a silver star device (for 5) and bronze star devices (1 each) on the campaign ribbon.

Oftentimes you will not see the stars referred to as a medal or device, as it was intended by the author of the document that the reader would understand from the context what was intended. 80 years later, families are trying to understand what is meant, having no frame of reference.