View Full Version : Discussion: Oldest Planetary Disk Discovered
2005-Jul-19, 04:22 PM
SUMMARY: Astronomers from the Harvard-Smithsonian Center for Astrophysics have found a dusty disk around a star which is 25 million years old. Planetary disks like this have been seen before, but never around a star which is so old; it's possible it'll never form planets. Most planetary disks make the transition within just a few million years, and the previous record was 10 million years. The disk still has a lot of gas in it, so researchers think it's still possible that it could form gas giants.
View full article (http://www.universetoday.com/am/publish/25_million_years_dust_disk_form_planets.html)
What do you think about this story? Post your comments below.
2005-Jul-19, 04:41 PM
This disk was observed with an inner radius of 65 million miles (Orbit of Venus) and an outer radius of 650 million miles (A little further than Jupiter). If I remember correctly that makes this the smallest such disk yet observed.
It is also interesting that this disk is around a PAIR of red dwarfs. I'm not sure how, but that might be a factor in the lack of planet forming.
2005-Jul-20, 06:22 AM
This is a very interesting animal in the planetary disc zoo. It definitely needs further study. I will be curious to know more about how the composition of the dust in this disc may differ from other discs. That will most likrly ultimately solve this little puzzle. The dust around this binary should be the less sticky kind.
2005-Jul-20, 06:23 AM
That was me above.
2005-Jul-22, 07:23 PM
Anyone remember, off-hand, how many proto-planetary disks have been discovered so far? I mean, I seem to be able to recall the number of exo-planets (~170) fairly easily, but disks?
In any case, seems we're a bit like the early years of quasar research ... a mere handful of examples, with theory not that well constrained by observation yet. It took, what, 30 years? to get from early quasar days to 2dF and SDSS with tens of thousands of them.
How do you write a 'news' story that takes 30 years to unfold?
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