[meteorite-list] Young Stars in Orion May Solve Mystery of Our Solar System
From: Starbits_at_aol.com <Starbits_at_meteoritecentral.com>
Date: Thu Apr 22 09:48:56 2004
<Scientists may have to give the Sun a little more credit. Exotic isotopes present in the early Solar System -- which scientists have long-assumed were sprinkled there by a powerful, nearby star explosion -- may have instead been forged locally by our Sun during the colossal solar-flare tantrums of its baby years. The isotopes -- special forms of atomic nuclei, such as aluminum-26, calcium-41, and beryllium-10 -- can form in the X-ray solar flares of young stars in the Orion Nebula, which behave just like our Sun would have at
such an early age. The finding, based on observations by the Chandra X-ray Observatory, has broad implications for the formation of our own Solar System.>
I thought this was interesting. The first thought that
comes to mind though is that if it is correct then the timelines for the early solar system are no longer valid. With a single influx of material at a specific point in time you get a set starting point of quantity of material and the decay and therefore time scales run from a single point. With solar flares producing these isotopes, then the material is input into solar system over a longer period so there is no starting point, rather there is a starting range. In addition the densities are not constant either in time, due to solar flare intensity variations, or in space, due to production along the flare track but not elsewhere.
This could cause some major problems with early solar system time scales. To explain why I need to cover some basics.
The isotopes in question Aluminum 26, ect. are extinct, they have decayed completely away. Researchers don't look for the Al 26 they look for its decay products. The amount of decay products are used to give the original amount of the Al 26. If you start the solar system with a set amount of Al 26 and it decays rapidly away then meteorites with less starting Al 26 formed later because there wasn't as much to put into them when they formed. Those with the most are the oldest and those with less or none are younger. By looking at what types of meteorites have how much Al 26 a sequence of events can be developed from the most primitive to the differentiated basaltic achondrites. Because the decay is a constant the time between these events can also be determined. Current estimates are that it took about 10 million years for planet formation.
However if solar flares produced the Al 26 then its density in the solar disk increased from zero to a maximum, remained at that maximum for an undetermined time and then decreased at an undetermined rate because as it decayed more was still being produced. Even if one assumes a homogeneous distribution in space and a nice gausian curve (smooth bell curve)for the increase and decrease in Al 26 density instead of a wildly fluxuating density, the Al 26 decay is no longer an accurate chronometer. For example if meteorite A is determined to have started with x amount of Al 26 and meteorite B also has x amount you can no longer assume they are of the same age. Meteorite B may have formed
10 million years later, or 5 million or 2 million or whenever the Al 26 density was the same. In addition if meteorite C has y amount which is exactly one Al 26 half life less than x you can't assume it is 700k years younger because the solar flares may have produced enough Al 26 so that despite the decay the "y" amount wasn't reached for 5 million years instead of 700k years. As a result early solar system chronology is back to square one if solar flares are the source of these isotopes.
By the way the age of formation of the solar system is not in question because different isotopes than these exotics are used for its determination.
Received on Sat 08 Sep 2001 12:22:13 AM PDT