From NASA: http://planetquest.jpl.nasa.gov/science/science_index.cfm<br /><br />The first true extrasolar planet discovery came in 1994, when Dr. Alexander Wolszczan, a radio astronomer at Pennsylvania State University, reported what he called "unambiguous proof" of extrasolar planetary systems. <br /><br />While scientists accepted his assessment, those hoping for evidence of planetary systems similar to our own were less than elated. Wolszczan had discovered two or three planet-sized objects orbiting a pulsar, rather than a normal star, in the Virgo constellation. A pulsar is a dense, rapidly spinning remnant of a supernova explosion. <br /><br />The first discovery of a planet orbiting a star similar to the Sun came in 1995. The Swiss team of Michel Mayor and Didier Queloz of Geneva announced that they had found a rapidly orbiting world located blisteringly close to a the star 51 Pegasi. Their planet was at least half the mass of Jupiter and no more than twice its mass. They had observed it indirectly, using the radial velocity method.<br /><br /> <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>
TFWThom has covered it well. All I can add is that you mentioned Barnards star. In that case, no planet was ever confirmed to my knowledge, even in recent years Barnards has been re studied and so far, no exoworld.<br /><br />The link below provides a good account of the history behind Barnards star extrasolar planet quest.<br /><br />http://www.astrobio.net/news/article1635.html <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
In this case, this is a historical classical example of how science often starts in well, fits and starts and failed attempts before finally hitting paydirt. This due of course to human and technical limitations. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>
What would the history of this system have been? (I'm very new to Astronomy, so please excuse my ignorance) - what I mean is, how long ago would the supernova have happened? Would it have once been a solar system like ours, or were the planets formed as a result of the supernova?<br /><br />thanks<br />Eilidh
I don't know the exact age of the pulsar, but the word "old" is often used in front of it <img src="/images/icons/smile.gif" />.<br /><br />While it's not known for certain how these planets formed, it seems likely that they formed as a result of the supernova. As I understand it, the prevailing theory is that they formed in a debri-disk around the neutron star that was itself the result of fall-back from the supernova ejecta. One of the big reasons for this is that these planets are known to be in nearly circular orbits, if they pre-existed the supernova then the abrupt decrease in the star's mass at the supernova event would have left the planets in a very eccentric orbit (if not ejecting them from the system all together). Also, evidence for debris disks have been found around some young neutron stars. If they were formed from a debris disk after the supernova, there's a good chance that they are composed predominately of very heavy metals (like nickel).<br /><br />There are actually three planets known to exist around this pulsar, and they're all actually pretty small in mass. The smallest one is only 2% the mass of the Earth - so it's basically an asteroid. That just goes to show how fabulous pulsars are for exquisitely precise measurements. You can find more information about these guys at for example Alex Wolszczan's website <div class="Discussion_UserSignature"> </div>
ah, thanks. Now you've explained it, of course they couldn't have been there before - all that energy exploding outwards... (right, I'll turn my brain on now...) - thanks for the link, its a nice clear page.
<font color="yellow">right, I'll turn my brain on now...</font><br /><br />It's a good question I think, it could still turn out that they pre-existed the supernova, or that the pulsar came very near another star and stole its planets. Without the actual data (lack of eccentricities) it wouldn't be so clear which mechanism is the most plausible. So don't feel bad <img src="/images/icons/smile.gif" />! <div class="Discussion_UserSignature"> </div>