We have recently discovered that CD -30 11223 is a binary composed of a whitedwarf orbiting a subdwarf of B spectral type in only 1.2 hours. This is by farthe shortest orbital period of any sdB+WD binary. The orbital separation of only0.6 solar radii implies that the subdwarf is very close to fill its Roche-lobe,making this system an optimal candidate for observations at X-ray energies.X-ray observations can give information on properties of the white dwarfunaccessible in other bands, which are particularly interesting given thepossibility that this close binary be the progenitor of a SN Ia via theso-called sub-Chandrasekhar double-detonation scenario.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2013-08-17T04:02:16Z/2013-08-17T18:45:36Z
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 Ulrich Heber, 2014, 'The Ultra Compact sdB+WD binary CD -30 11223', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-wwx2a0y
