Neutron Star Bites Off More Than It Can Chew
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The European Space Agency's XMM-Newton space observatory has watched a faint star flare up at X-ray wavelengths to almost 10 000 times its normal brightness. Astronomers believe the outburst was caused by the star trying to eat a giant clump of matter.
The flare took place on a neutron star, the collapsed heart of a once much larger star. Now about 10 km in diameter, the neutron star is so dense that it generates a strong gravitational field.
The clump of matter was much larger than the neutron star and came from its enormous blue supergiant companion star.
"This was a huge bullet of gas that the star shot out, and it hit the neutron star allowing us to see it," says Enrico Bozzo, ISDC Data Centre for Astrophysics, University of Geneva, Switzerland, and team leader of this research.
The flare lasted four hours and the X-rays came from the gas in the clump as it was heated to millions of degrees while being pulled into the neutron star's intense gravity field. In fact, the clump was so big that not much of it hit the neutron star. Yet, if the neutron star had not been in its path, this clump would probably have disappeared into space without trace.
Monitoring Supergiant Fast Xray Transients with Swift. Results from the first year
by P. Romano, L. Sidoli, G. Cusumano, V. La Parola, S. Vercellone, C. Pagani, L. Ducci, V. Mangano, J. Cummings, H.A. Krimm, C. Guidorzi, J.A. Kennea, E.A. Hoversten, D.N. Burrows, N. Gehrels
(Mon. Not. R. Astron. Soc. 000, 112 (2009), 10 July 2009)