Between Cepheids and the Cosmos
1 Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge MA 02138, USA
2 Villanova University, Department of Astronomy, Villanova, PA 19085, USA
3 University of Toronto, Dept of Astronomy Astrophysics, 60 St. George St. Toronto, ON M5S 3H4, Canada
4 Iowa State University, A313E Zaffarano, Dept. of Physics and Astronomy, Ames, IA 50010, USA
5 MIT Haystack Observatory, Westford MA, 01886, USA
6 MIT Kavli Institute for Astrophysics and Space Research, 70 Vassar St., Cambridge MA 02139, USA
Published online: 8 September 2017
The X-ray observations of three classical Cepheids produce a surprising result. At approximately the phase of maximum radius there is a sharp increase in X-ray flux above the normal “quiescent” level. The relation of this new upper atmosphere diagnostic to other phenonena above the photosphere is discussed.
© The Authors, published by EDP Sciences, 2017
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