Tycho Brahe's 1572 supernova

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<p>There was a really neat article that just came out on astro-ph yesterday (and will be published in Nature) about Tycho Brahe's 1572 supernova - see http://arxiv.org/abs/0810.5106 .</p><p>As the story goes, in 1572 Tycho Brahe was going home when he noticed a new star in Cassiopeia. Intrigued, he carried out very detailed measurements of the supernova which were instrumental in shattering the long-held belief that the heavens beyond the moon are unchanging.&nbsp; In 1952 the supernova remnant from this explosion was discovered and detailed studies of this remnant have suggested that the explosion was a Type Ia supernova (we think these are cases where a white dwarf is feeding on a companion star until it reaches a mass limit of ~1.4 solar masses, when it becomes unstable, and explodes). In 2004 the companion star that the putative white dwarf was feeding on was possibly discovered. Very recently people have discovered light echoes from several historical supernovae, including Tycho's 1572 supernova. Basically, the star actually exploded about 12,800 years ago, the light from the explosion took ~12,400 years to travel to Earth, arriving in 1572. But some of the light that left the supernova in a different direction lit up dust in the interstellar medium which we can also see. Since the total path length from the site of the explosion to the dust and then to Earth is longer than the path length from the explosion site directly to the Earth, over time you see dust lit up further and further from the supernova site, (see http://antwrp.gsfc.nasa.gov/apod/ap060125.html for an example from the supernova 1987a). Today we see light from Tycho's 1572 supernova reflecting off dust that lies in a position where the total path length from the supernova site to the dust to us is 400 light years farther than the path directly from the supernova to us. In the article that appeared yesterday on astro-ph, the authors took a deep spectrum of the light echo from Tycho's 1572 supernova and found that it is exactly like the spectrum of a "normal" Type Ia supernova that we might see go off in a distant galaxy.</p><p>&nbsp;I think this is a really cool result for a number of reasons. First of all, it's just really neat that you can still see the light from an explosion that occurred more than 4 centuries ago - it really gives a good illustration of how vast space is.&nbsp; From a scientific standpoint, if you can associate a specific type of supernova with its remnant you can learn a lot about the processes that make most of the heavy elements in the universe. People can study a supernova remnant to figure out how much iron vs. titanium vs. calcium vs. what-have-you was produced in the explosion, but it's very rare to have a supernova go off close enough to us to be able to study both the supernova itself (which tells us what exactly is exploding) and the remnant. It's very cool then that people are figuring out how to effectively go back in time to observe long-past explosions that left the remnants that we can now study in detail.&nbsp; </p> <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

<p>Cool stuff!</p><p>Once again I waill be waiting by the mailbox for Nature to arrive!!</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[weeman]

Wow, that's wild! I never knew such phenomena existed in the universe! <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>