|Title||X-Rays from Cepheids: Hints of Mass Loss?|
|Author||Dr Nancy Remage Evans|
|Description||Recent Cepheid X-ray observations have found the surprising result of increased emission just after maximum radius, a pulsation phase when the photosphere is quiescent. Recent interferometric observations of Cepheids have found circumstellar envelopes (also surprising) which may be related and raise questions of possible mass-loss and increased infrared (IR) flux which would be important in the use of the IR Leavitt (PL) relation for cosmology. The requested XMM observation of the Cepheid V473 Lyr at the phase of maximum radius will provide a diagnostic of the elusive upper atmosphere activity, and specifically the dependence on luminosity, mass, pulsation amplitude and mode.|
|Publication||No observations found associated with the current proposal|
|Instrument||EMOS1, EMOS2, EPN, OM, RGS1, RGS2|
|Mission Description||The European Space Agency's (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESA's 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 Earth's 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.
|Publisher And Registrant||European Space Agency|
|Credit Guidelines||European Space Agency, 2020-04-12T22:00:00Z, 082120, 17.56_20190403_1200. https://doi.org/10.5270/esa-i8i2s0x|