Prospects for a Multi-Wavelength Characterization of Cepheid Envelopes

¹ LESIA, Observatoire de Paris, CNRS UMR 8109, UPMC, Université Paris Diderot, 5 place Jules Janssen, 92195 Meudon, France
² Center for High Angular Resolution Astronomy, Georgia State University, PO Box 3965, Atlanta, Georgia 30302-3965, USA

Abstract

Until recently, Cepheids were considered implicitely as "nak- ed" stars, i.e. devoid from circumstellar material. In 2005, VINCI/ VLTI and FLUOR/CHARA interferometric observations revealed circumstellar envelopes (hereafter CSEs) around Cepheids. Their presence may have an impact on the determination of distances, and could bear testimony of their mass-loss history. Although their observation is made difficult by the brightness of the Cepheids themselves, many observation techniques have the potential to improve our knowledge of their physical properties. We discuss in particular long-baseline interferometry, visible and infrared imaging, spectroscopy and radio observations.