Very recently, it has been discovered that ZTF J213056.71+442046.5 is a binarysystem composed of a white dwarf orbiting a hot subdwarf star in only 39 min.This is the shortest orbital period of any sdOB+WD binary. The orbitalseparation implies that the subdwarf fills its Roche-lobe, making this system anoptimal candidate for observations at X-ray energies. The likely presence ofX-ray emission is further strengthened by the finding that the periodicmodulation of the optical light curve can be explained only invoking thepresence of an accretion disk around the white dwarf, which occults the subdwarfmass donor star. X-ray observations can give important information on the masstransfer rate, on the properties of the WD and on the evolution of this unique binary.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2021-01-05T23:01:46Z/2021-01-06T18:53:26Z
Version
18.02_20200221_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, Dr SANDRO MEREGHETTI, 2022, 'The ultra-compact sdOB+WD binary ZTF J213056.71+442046.5', 18.02_20200221_1200, European Space Agency, https://doi.org/10.57780/esa-sziypb8
