|Title||The orbital period decay of HMCnc: G.W. emission vs magnetic stresses|
|Author||Prof Gian Luca Israel|
|Description||HMCnc is a two white dwarfs system with the shortest orbital period (321s). The X-ray monitoring of this unique source over the last 20 years, made it possible to assess that the modulation is decreasing at about 1ms-yr. Two competing scenarios have been suggested for HMCnc: the direct impact model, involving matter accretion, and the unipolar inductor, which considers the WDs as components of an electric circuit. In the former the orbital decay is expected to be ruled by GW emission only and a second period derivative <-1E-7s-yr-yr is expected, while in the latter magnetic stresses are expected to produce a larger component. The new pointing we are requesting will allow us to detect a second period derivative or to set a tight upper limit, thus discerning between the two competing models.|
|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, 2017-05-17T22:00:00Z, 078467, 17.56_20190403_1200. https://doi.org/10.5270/esa-b84dp53|