We are now immersed in the middle of a stellar mystery: why (and how) areClassical Cepheids producing X-rays? We propose phase-constrained & betterexposed XMM observations in Cycle 9 to solve this mystery, and initiate a leapforward in our understanding of Cepheid atmospheres, pulsations, winds, shocksand internal structures. It is worth noting that: all three Cepheids observed todate by XMM have successfully been detected and, more importantly, our recentXMM results mark the first ever unambiguous X-ray detections of Cepheids. Themajor aim of this proposal is to obtain deeper XMM observations of twopreviously observed Cepheids (Polaris & beta Dor) at critical pulsation phasesto understand the mechanism(s) by which they produce X-rays.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2010-05-01T09:12:01Z/2010-05-01T19:43:10Z
Version
17.56_20190403_1200
Mission Description
The European Space Agencys (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESAs second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations. Since Earths atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis.
European Space Agency, Prof Edward Guinan, 2011, 'The Secret X-ray Lives of Cepheids: Are Classical Cepheids X-ray VariablesquestionMark', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-l5aakro
