X-Rays in Cepheids: XMM-Newton Observations of η Aql
Mérand, Antoine; Drake, Jeremy J.; Guzik, Joyce A.; Evans, Nancy Remage; Marengo, Massimo; Gallenne, Alexandre; Kervella, Pierre; Guinan, Edward; Engle, Scott; Pillitteri, Ignazio; Hocdé, Vincent; Matthews, Lynn D.; Wolk, Scott; Günther, H. Moritz; Neilson, Hilding; Moschou, Sofia
United States, Italy, France, Canada, Poland, Chile, Germany
Abstract
X-ray bursts have recently been discovered in the Cepheids δ Cep and β Dor modulated by the pulsation cycle. We have obtained an observation of the Cepheid η Aql with the XMM-Newton satellite at the phase of maximum radius; the phase at which there is a burst of X-rays in δ Cep. No X-rays were seen from the Cepheid η Aql at this phase, and the implications for Cepheid upper atmospheres are discussed. We have also used the combination of X-ray sources, as well as Gaia and 2MASS data, to search for a possible grouping around the young intermediate mass Cepheid. No indication of such a group was found. * Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).