Ad Astra, “To the Stars,” shows us two boys releasing a dove. The younger, looking up at the bird that he holds over his head, prepares to let it fly. An older boy, seated on the ground and bracing himself on his left elbow, steadies his young friend with his right hand. Ad Astra symbolizes the virtues of aspiration and striving for a higher purpose.The half-life-size, bronze group is the last work by the Boston based artist, Kahlil Gibran (d. 2008), whose sculptures may be found throughout the city. His family gave Ad Astra to Boston in Gibran’s memory. It is displayed on a granite pedestal in Childe Hassam Park in the South End.