Irvine, WM2024-04-262024-04-262006-01-01https://doi.org/10.1093/astrog/47.2.2.6-bhttps://hdl.handle.net/20.500.14394/2882<p>The published version is located at <a href="http://www.blackwellpublishing.com/products/journals/aag/AAG_April06/aag_47207.htm">http://www.blackwellpublishing.com/products/journals/aag/AAG_April06/aag_47207.htm</a></p>Astrophysics and Astronomyarticle