Chandra/HETGS spectroscopy of 4U 1626-67 detects Doppler pairs of broad Keplerian Ne/O lines, and Ne/O absorption edges much stronger than ISM values.Based on the inferred local Ne/O ratio, the mass donor is likely the low-masscore of a crystallized C-O or O-Ne-Mg white dwarf, and may be the prototypefor an emerging class of ultracompact binaries with exotic donors. We proposean 80 ks XMM observation with 3 principal goals: (1) to establish the donor composition by measuring the edges of Ne,O,Mg,and C; (2) to study the accretionflow structure through Doppler tomography using the H-like lines; (3) to studydisk warping by correlating line strengths with the known UV variability of thesource. The 20 ks XMM GTO observation will not meet any of these goals.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2003-08-20T05:55:48Z/2003-08-21T05:14:56Z
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 Deepto Chakrabarty, 2004, 'High-Resolution Spectroscopy of the O/Ne-Rich Ultracompact Binary 4U 1626-67', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-qetserr
