<p>NASA image release August 17, 2010
</p><p>Astronomers using NASA's Rossi X-ray Timing Explorer (RXTE) have found the first fast X-ray pulsar to be eclipsed by its companion star. Further studies of this unique stellar system will shed light on some of the most compressed matter in the universe and test a key prediction of Einstein's relativity theory.
</p><p>Known as Swift J1749.4-2807 -- J1749 for short -- the system erupted with an X-ray outburst on April 10. During the event, RXTE observed three eclipses, detected X-ray pulses that identified the neutron star as a pulsar, and even recorded pulse variations that indicated the neutron star's orbital motion.
</p><p>To view a video of this pulsar go here: &lt;a href="<a rel="nofollow" class="external free" href="https://www.flickr.com/photos/gsfc/4901238111">https://www.flickr.com/photos/gsfc/4901238111</a>"&gt;www.flickr.com/photos/gsfc/4901238111&lt;/a&gt;
</p><p>To read more <b>&lt;a href="<a rel="nofollow" class="external free" href="http://www.nasa.gov/topics/universe/features/eclipsing-pulsar.html">http://www.nasa.gov/topics/universe/features/eclipsing-pulsar.html</a>" rel="nofollow"&gt;click here&lt;/a&gt;</b> 
</p><p>Credit: NASA/GSFC
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<a rel="nofollow" class="external text" href="https://www.flickr.com/people/24662369@N07">NASA Goddard Space Flight Center</a> from Greenbelt, MD, USA
2010-07-26 14:31
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/gsfc/4901241763/">Eclipsing Pulsar Promises Clues to Crushed Matter</a>