RX J0822-4300

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RX J0822-4300
Puppis scale.jpg
motion of the neutron star RX J0822-4300 from the Puppis A supernova event.
Observation data
Epoch 1952 (equinox J2000.0)[1]      Equinox 1952 (equinox J2000.0)[1]
Constellation Puppis
Right ascension 08h 23m 8.16s[2]
Declination −42° 41′ 41.4″[2]
Apparent magnitude (V) ~24[2]
U−B color index  ?
B−V color index  ?
Variable type None
Radial velocity (Rv) 672 km/s
Distance 2,000 pc
Galactic coordinates 260.3841 -03.4718
Mass M
Radius R
Luminosity L
Temperature K
Metallicity ?
Rotation ?
Age ? years
Other designations
EQ 0820-4250, PSR J0822-4300, 1RXS J082158.2-430022.

RX J0822-4300, often referred to as a "Cosmic Cannonball", is a radio-quiet neutron star currently moving away from the center of the Puppis A supernova remnant at over 3 million miles per hour (5 400 000 km/h; 1500 km/s; ~0.5% the speed of light), making it one of the fastest moving stars ever found. Astronomers used NASA's Chandra X-ray Observatory to observe the star over a period of five years to determine its speed. At this velocity the star will be ejected from the galaxy millions of years from now.

Although the cosmic cannonball is not the only hypervelocity star discovered, it is unique in the apparent origin of its speed. Others may have derived theirs from a gravitational slingshot around the Milky Way's suspected supermassive black hole, Sagittarius A*. Current theories fail to explain how such speeds can be attained from a supernova explosion. It could be a possible quark star.

However, a more recent (2012) analysis by the same group yielded a more modest recoil velocity of 672±115 km/s which is much less problematic theoretically.[3]

See also[edit]


  1. ^ Hui, C. Y.; Becker, W. (2006). "Probing the proper motion of the central compact object in Puppis-A with the Chandra high resolution camera". Astronomy and Astrophysics. 457 (3): L33. arXiv:astro-ph/0606750free to read. Bibcode:2006A&A...457L..33H. doi:10.1051/0004-6361:20065941. 
  2. ^ a b c Hui, C. Y.; Becker, W. (2006). "X-ray observations of RX J0822-4300 and Puppis-A" (PDF). Astronomy and Astrophysics. 454 (2): 543. arXiv:astro-ph/0508655free to read. Bibcode:2006A&A...454..543H. doi:10.1051/0004-6361:20053554. 
  3. ^ Becker, Werner; Prinz, Tobias; Frank Winkler, P.; Petre, Robert (2012). "The Proper Motion of the Central Compact Object RX J0822-4300 in the Supernova Remnant Puppis A". arXiv:1204.3510free to read [astro-ph.HE].