Dr. Mark Giampapa has studied stars in M67 for many years, and his team has identified one particular member that is a closer twin to the Sun than any star previously studied. Some of this work is described in the March cover story. Mark also studies near-solar twins to measure their level of magnetic activity, research briefly described on page 35 of the March 2009 issue.
In early January Mark spoke on the phone with Sky & Telescope editor Robert Naeye to talk about his research on solar twins. In Part 1, Giampapa defines what astronomers mean by a solar twin, and how his studies of the magnetic activity of Sun-like stars give us insights on the activity of the Sun itself, and how future changes might impact human society. In Part 2, he talks about the likelihood that the Sun was born in M67, how stars in this cluster are similar to and different from the Sun, and how astronomers date the ages of stars. Both parts last about 10 minutes.