[meteorite-list] Bassikounou OCTOBER 16th

[Peter Marmet]

Hi Doug

the analysis was done by P. Weber, PPGUN.

The results are from the Meteoritical Bulletin Database.

In the Meteoritical Bulletin Database the fall date is still Oct. 16 -
so officially it's Oct. 16, isn't it!

I only found a hint why some sources mention Oct. 12 for the fall date!

Cheers, Peter





2009/10/11 Mexicodoug <mexicodoug at aim.com>:
> Hi List, Peter,
>
> Could you give a little more detail, as 22Na has a half life of about 950
> days and the experimental uncertainty of that particular measurement
> apparently used to calculate the ratio was 11.6%, not to mention worse
> uncertainties with the 26Al. It says the measurement was between December
> and January of 2006.
>
> So for starters, did they measure the meteorite 9 months before it fell?
> OK, so maybe it is a typo in the link you gave (source or on line
> Meteoritical Bulletin, but the same January 2006 date is currently on
> Svend´s website) and say they are both typos which may or may not say
> something about precision: and should read January 2007.
>
> If we assume the measurements were taken about 75 days after the fall and we
> throw around a ten percent order of magnitude as the possible measurement
> error, would not the difference of 4 days (October 12 vs. Oct. 16) be
> totally lost in the error?
>
> It is more likely the measurements were just to prove it was a fresh fall,
> but the ability to distinguish four days based on a bunch of assumptions of
> the original composition seems far-fetched to me. That must be what the
> scientists set out to prove.
>
> So, maybe the gamma spectroscopist had received the October 12 date and only
> set out to prove it was reasonable. Surely if they had received the October
> 16 date, they would have allowed it as consistent as well - after all, over
> 99.7% of the 22Na would still be there (did I do that right?), and this is
> dwarfed by the experimental error.
>
> As Jim mentioned I think a real witness needs to speak up ... the press, as
> reported by Svend Buhl, has October 16 as the fall date. So at the moment,
> it would seem the press is preferable to insignificant digits being
> extended...
>
> Best wishes,
> Doug
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: Peter Marmet <p.marmet at sunrise.ch>
> To: Meteorite-list at meteoritecentral.com
> Sent: Sun, Oct 11, 2009 3:28 pm
> Subject: Re: [meteorite-list] Bassikounou OCTOBER 16th
>
>
>
> Hello Thomas,
>
> Cosmogenic radionuclides:
> (P. Weber, PPGUN) Gamma-spectroscopy performed in December-January
> 2006 showed the presence of the following radionuclides: 48V, 46Sc,
> 56Co, 54Mn, 58Co, 7Be, 51Cr, 57Co, 22Na, 26Al and 60Co.
>
> Recalculated to 12 October 2006 22Na was 38.0±2.2 and 26Al 31.5±2.1
> (both dpm/kg), the activity ratio of 1.21 is fully consistent with a
> fall on that date.
>
> More info here: http://kuerzer.de/1u0Y557jF
>
> Cheers,
> Peter
>
>
>
>
>
>
>
>
> 2009/10/11 Thomas Webb <webbth1 at yahoo.com>:
>>
>> Jim and List,
>> The bulletin shows a discrepancy concerning the fall date.  In the
>
> data table
> it gives October 12, 2006 but in the writeup it is October 16.  I belive I
> was
> the first to offer any on ebay and at that time I gave the fall date as Oct.
> 12
> and still have that date in my
> database.  However, perhaps a corrected date was
> offered later.
>>
>> Can someone give us confirmation of the actual date that it fell?
>> Thanks,
>> Thomas
>>
>> --- On Sun, 10/11/09, Jim Strope <nwa482 at comcast.net> wrote:
>>
>>> From: Jim Strope <nwa482 at comcast.net>
>>> Subject: [meteorite-list] Bassikounou OCTOBER 16th
>>> To: "Meteorite Central" <meteorite-list at meteoritecentral.com>
>>> Date: Sunday, October 11, 2009, 10:29 AM
>>>
>>>
>>> http://tin.er.usgs.gov/meteor/metbull.php?code=44876
>>>
>>> Jim Strope
>>> 421 Fourth Street
>>> Glen Dale, WV  26038
>>>
>>> http://www.catchafallingstar.com/
>>> ______________________________________________
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>>
>>
>>
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