GP Com is a helium-star cataclysmic variable - a short-period (2792s) semidetached binary consisting of a CO white dwarf primary and a He white dwarfsecondary. GP Com is X-ray bright, nearby (d<100 pc), very likely a halo (PopII) object, and has highly anomalous abundances (little-to-no H, reduced C andO, enhanced N and Ne, and greatly reduced heavy metals). The enhanced Nabundance is hinted at by an existing ASCA spectrum, while the optically-derived abundances imply that the emission at virgul 1 keV is due not to Fe L-shellemission but to H- and He-like Ne (a la the LMXB 4U 1626-67). We propose a 41.9 ks XMM observation of GP Com to determine the nature (abundances, emission measure distribution, etc.) of the X-ray spectrum of this unusual CV.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2001-01-03T13:03:17Z/2001-01-04T04:45:02Z
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, Dr Christopher Mauche, 2002, 'GP Com: Helium Cataclysmic Variable and Nitrogen and Neon Monster', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-n65vh0l
