The globular cluster LMXB 4U1820-30 consists of a neutron star and a Hedegenerate dwarf in an 11 minute binary. Based on existing Einstein OGS & SSSspectra, ASCA spectra, and an evolutionary model of 4U1820, we argue that theX-ray spectrum of this famous binary is the superposition of a strong continuumand the emission lines and recombination continua of a photoionized plasmawhich is strongly enhanced in light elements. XMM spectroscopy of 4U1820 willconstrain the relative abundances of this plasma and thereby strongly constrainthe evolutionary history the binary. The strengths and widths of the lines andrecombination continua will constrain the plasma emission measure distribution,electron temperature, optical depth, density, and radius of formation within
Instrument
EMOS1, EMOS2, OM, RGS1, RGS2
Temporal Coverage
2001-10-09T09:12:01Z/2001-10-09T20:12:21Z
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, 'X-ray Spectroscopy of the 11 Minute LMXB 4U1820-30', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-1r2p6up
