HD49798/RX J0648.0-4418 is the only known X-ray binary in which the donor is ahot subdwarf of O spectral type. The compact object (a white dwarf or a neutronstar) has a spin period of 13.2 s and has been steadily spinning up at2x10^{-15} s/s for the last 20 years. Independently of its NS or WD nature, thisspin-up is difficult to explain with the angular momentum that accretion cansupply. An alternative explanation requires the presence of a young WD, still incontracting phase. We propose a fulfil observation to extend the phase connectedtiming solution in order to investigate the timing properties of this uniquebinary and shed light on the nature of the compact object.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2018-11-08T10:20:38Z/2018-11-08T23:47:51Z
Version
PPS_NOT_AVAILABLE
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, Dr SANDRO MEREGHETTI, 2019, 'Long-term phase-connected timing of the unique X-ray binary HD49798', PPS_NOT_AVAILABLE, European Space Agency, https://doi.org/10.5270/esa-sk20he0
