[meteorite-list] Cold Asteroids May Have ASoftHeart(AllendeMeteorite)

From: Richard Montgomery <rickmont_at_meteoritecentral.com>
Date: Sat, 16 Apr 2011 19:43:28 -0700
Message-ID: <86213246AF6143F3AB5CEC7C7123C4D5_at_bosoheadPC>

Okay, List, ready for another neophyte question? Here goes:

Looking FROM space to the Earth, does the absorption spectra of our planet
in the 3-micron band (water) measure proportionate, i.e. zero in that band,
which would relegate much of what is seen of US to be non-reflective? Do
such measurements exist?

Curious Richard Montgomery


----- Original Message -----
From: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
To: <lebofsky at lpl.arizona.edu>
Cc: "metlist" <meteorite-list at meteoritecentral.com>; "MEM"
<mstreman53 at yahoo.com>
Sent: Saturday, April 16, 2011 1:31 PM
Subject: Re: [meteorite-list] Cold Asteroids May Have
ASoftHeart(AllendeMeteorite)


> Hi, Larry, List,
>
> As usual, I grabbed an idea and ran off the cliff
> with it; now Larry has handed me the anvil, just
> like I was the well-known cartoon Coyote. And also,
> as usual, Larry is right. Must be gratifying, having
> someone who has to keep posting that you are right,
> Larry...
>
> Larry said
>> The presence of hydrated silicates on asteroid
>> 2 Pallas dates back to the early 1980s
>
> Larry is referring modestly to:
> Feierberg, M. A.; Larson, H. P.; LEBOFSKY, L. A. (1982).
> "The 3 Micron Spectrum of Asteroid 2 Pallas.".
> Bulletin of the American Astronomical Society 14: 719.
> Unfortunately, the ADS system only gives the page with
> the title at the bottom of the page and then cuts off the
> article which starts on the next page...
>
> Although, in my defense, I could cite:
> http://www.lpi.usra.edu/books/AsteroidsIII/pdf/3031.pdf
> in which there is a table that shows Pallas (B-class)
> with ZERO absorption in the 3-micron band (water,
> in other words). Also has "Lebofsky, L. A." as an author.
>
> Links to all or part of Larry's 304 articles:
> http://adsabs.harvard.edu/cgi-bin/nph-abs_connect?return_req=no_params&author=Lebofsky,%20L.%20A.&db_key=AST
>
> Looking for water (or anything like it) by peering through
> the wet sodden atmosphere of Earth is a chancy business;
> the data needs to massaged. I'm not suggesting that the
> data isn't reliable, just that it's likely to have fuzzy edges.
>
> Just an abstract, but summarizes well:
> http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WGF-4731CCX-DV&_user=10&_coverDate=12%2F31%2F1983&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort=d&_docanchor=&view=c&_searchStrId=1720558577&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=b3a90d3f66329ead2085b10dd7dbde6b&searchtype=a
> "High resolution spectroscopic observations of
> asteroid 2 Pallas from 1.7-3.5 ?m are reported.
> These data are combined with previous measurements
> from 0.4-1.7 ?m to interpret Pallas' surface mineralogy.
> Evidence is found for low-Fe-2+ hydrated silicates,
> opaque components, and low-Fe-2+ anhydrous silicates.
> This assemblage is very similar to carbonaceous chondrite
> matrix material such as is found in type CI and CM
> meteorites, but it has been subjected to substantial
> aqueous alteration and there is a major extraneous
> anhydrous silicate component. This composition is
> compared to that of asteroid 1 Ceres. Although there
> are substantial differences in their broad band spectral
> reflectances, it appears that both asteroids are genetically
> related to known carbonaceous chondrites."
>
> These folks thinks it's drier than Larry's studies:
> Sato, Kimiyasu; Miyamoto, Masamichi; Zolensky, Michael E.
> (1997). "Absorption bands near 3 m in diffuse reflectance
> spectra of carbonaceous chondrites: Comparison with asteroids"
> http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1997M%26PS...32..503S&amp;data_type=PDF_HIGH&amp;whole_paper=YES&amp;type=PRINTER&amp;filetype=.pdf
>
> More new looks. These guys think Pallas is smaller
> than previously thought, they say, and they have refined
> that strange shape (very nice graphics):
> http://www.eso.org/sci/activities/santiago/projects/PlanetaryGroup/journal_club/slides/ESO.JournalClub-2007.08.14-BenoitCARRY.pdf
> And if it were smaller but the mass is correct, then Pallas'
> density would be higher. That would have implications
> for trying to mentally reconstruct it...
>
> And of course in Larry's second reference, Pallas is
> bigger than we thought and hence less dense. This
> suggests we have a way to go in order to pin this down.
>
> It should be explained (if anybody is still following this)
> that Pallas is not easy to observe -- it dark and its
> eccentric orbit carries it far enough away to be very
> dim except at those short intervals when it's close to
> the Sun and the Earth passes it at its nearest approach.
>
> Is there a general trend toward our perceiving primitive
> meteorites as drier than we thought?. See:
> "Primitive Meteorites Depleted in Volatiles "(press release)
> quotes from Phil Bland and Monica Grady:
> http://www.pparc.ac.uk/Nw/meteorite.asp
>
> Obviously, Pallas is not "dry" in the same sense as the
> Moon or Mercury and I was wrong to imply that,
> although it might be less than 10%. The Sato paper
> suggests it's more like Renazzo than like Larry's
> suggestion of Murchison, or about half as "wet."
> 5%?
>
> There's no substitution for actually going there and
> looking it over for yourself, which someday we'll be
> able to. Until then, we'll have to have fun guessing
> and peeking through the wet murk of Earth.
>
>
>
> Sterling K. Webb
> ---------------------------------------------------------------------------------
> ----- Original Message -----
> From: <lebofsky at lpl.arizona.edu>
> To: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
> Cc: "metlist" <meteorite-list at meteoritecentral.com>; "MEM"
> <mstreman53 at yahoo.com>
> Sent: Saturday, April 16, 2011 11:27 AM
> Subject: Re: [meteorite-list] Cold Asteroids May Have A
> SoftHeart(AllendeMeteorite)
>
>
>
> Hi Sterling
>
> Sorry for taking so long in responding, but I am still catching up from
> being out of email access for three days this weekend and I missed this
> one.
>
> The presence of hydrated silicates on asteroid 2 Pallas dates back to the
> early 1980s and has been confirmed numerous times and spectrally matches
> Murchison.
>
> So unless you imply low water as being only about 10% water by mass,
> Pallas is not dry!
>
> Larry
>
> http://www.lpi.usra.edu/meetings/LPSC98/pdf/1310.pdf
>
> http://adsabs.harvard.edu/abs/2008DPS....40.2204S
>
>>> It shows signs of olive and pyroxene,
>>
>> I meant OLIVINE, of course.
>>
>>> when we got their...
>>
>> and THERE. Spell checkers don't catch
>> these mistakes, only working brains, so...
>> New rule: No more Posts after midnight.
>>
>>
>> Sterling K. Webb
>> ---------------------------------------------------------
>> ----- Original Message -----
>> From: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
>> To: "MEM" <mstreman53 at yahoo.com>; "Richard Montgomery"
>> <rickmont at earthlink.net>; "metlist"
>> <meteorite-list at meteoritecentral.com>
>> Sent: Thursday, April 14, 2011 1:21 AM
>> Subject: Re: [meteorite-list] Cold Asteroids May Have A
>> SoftHeart(AllendeMeteorite)
>>
>>
>> Hi,
>>
>> Way too much stuff here to deal with all,
>> but I have a word about 2 Pallas as a
>> "Carbonaceous parent body."
>>
>> Pallas has a silicate spectrum. A great many
>> bodies do. It shows signs of olive and pyroxene,
>> with low iron and water. If it resembles any
>> Carbonaceous chondrite, it's a CR with no
>> hydrated minerals or very little.
>>
>> Pallas is very dark, with an albedo of 12%-14%,
>> almost as dark as our moon, whose albedo is
>> 7% to 8%. Yes, when we look at the Moon
>> at night, it looks BRIGHT, but in reality, the
>> Moon is about the color and reflectivity of
>> a huge lump of black anthracite coal.
>>
>> The fact that it doesn't look like a lump of coal
>> in pictures taken on the Moon or looked to the
>> astronauts as a very light grey demonstrates
>> the ability of the human mind to scale image
>> intensity to the Earth norm and to expose film
>> to achieve similar results.
>>
>> Pallas is a little brighter than the Moon but
>> some darker than Mercury which is about 15%
>> to 16% albedo. Of course, if a human eye was ON
>> Mercury, the planet would appear to us as blazing
>> white under sunlight more than 2.5 times brighter
>> than here at Earth.
>>
>> The density of Pallas is about 2.8. The similar
>> sized Vesta is 3.43, our Moon 3.35, Mercury . For
>> comparison, Earth's crustal rocks, mostly silicates,
>> have a mean density of about 3.0. It seems unlikely
>> that Pallas has an iron core. Like the Moon and
>> Mercury, it seems to be essentially waterless.
>>
>> The spectral "classifications," both the Tholin and
>> the 2Mass, classify a great many asteroids as varieties
>> of "Carbonaceous," but we see far fewer Carbonaceous
>> meteorites than they see asteroids!
>>
>> We spent many decades trying to analyze the surface
>> of the Moon spectroscopically, it being so conveniently
>> close and all, but none of it told us that much about
>> what we'd find when we got their. Similarly, spectral
>> studies of Mars from Earth are largely forgotten for
>> the same reason: they were wrong.
>>
>> I expect Pallas to be excessively dry and waterless,
>> made of excessively dark rock, primitive in composition,
>> likely has little plagioclase on the surface, probably
>> isn't "differentiated" and lacks basalt melts. But hey!
>> I'm just guessing.
>>
>> There is a chance that we may get a look at Pallas.
>> When the Dawn mission is mission is finished at Ceres,
>> if all systems are functioning and fuel supplies are
>> within parameters, it COULD be sent on a flyby of
>> Pallas. Dawn couldn't orbit it, but it could grab a lot
>> of lovely snapshots on that pass.
>>
>> Of course, we'd have to get it funded by Congress...
>>
>> Groan.
>>
>>
>>
>> Sterling K. Webb
>> --------------------------------------------------------------------------
>> ----- Original Message -----
>> From: "MEM" <mstreman53 at yahoo.com>
>> To: "Richard Montgomery" <rickmont at earthlink.net>; "metlist"
>> <meteorite-list at meteoritecentral.com>
>> Sent: Wednesday, April 13, 2011 9:31 PM
>> Subject: Re: [meteorite-list] Cold Asteroids May Have A Soft
>> Heart(AllendeMeteorite)
>>
>>
>>> Let me play politician and ask to "revise and extend my remarks".
>>> There are
>>> asteroid gurus on the list who are more likely able to address this
>>> and I'd like
>>> to hear from them. Your theory/question is partially in the right
>>> direction so
>>> let me re-frame it. I believe we have "likely" detected all the
>>> existent
>>> asteroids in our inner solar system which are large enough to have
>>> formed
>>> basalt/cores--aka differentiated. That size is hard
>>> overlook(100-300km
>>> minimum?). I read somewhere that as many as 12-20 major/minor planets
>>> would
>>> have formed in the early solar system that are no longer with us as
>>> major/minor
>>> intact bodies.( i.e. absorbed or ejected)
>>>
>>> As to meteorite parent bodies, what we have yet to inventory and, for
>>> which we
>>> have not had a specimen drop by Earth for comparison, are these long
>>> ago
>>> disrupted bodies. These bodies which now are represented only by
>>> minor,
>>> irregular, slivers, slices, and rubble piles within certain swarms of
>>> asteroids
>>> in different sectors of the solar system.
>>>
>>> There is a "diogenite-like" spectrum coming from an outer-belt
>>> asteroid whose
>>> orbit proves it cannot be related to Vesta. I mentioned the caveat
>>> that there
>>> may be some remnants of asteroids which were differentiated in the
>>> early solar
>>> system and for whatever reason are no longer in tact. We may only
>>> have a
>>> fraction of the original large body such that while we have located
>>> all the
>>> differentiated intact ergo larger asteroids, we may need to be
>>> looking for
>>> shards of former bodies to match meteorites from our collections. The
>>> reason
>>> all our "HED"s are from Vesta is probably that Vesta is on our "mail
>>> route" and
>>> quantum transport from Vesta to Earth is a favorable happenstance.
>>>
>>> "1459 Magnya: Orbits in the outer main belt, too far from Vesta to be
>>> genetically related. May be the remains of a different ancient
>>> differentiated
>>> body that was shattered long ago." Spectrum is diogenite-like
>>>
>>> Another candidate which may be the source of olivine-diogenites but is
>>> a chunk
>>> off Vesta:
>>> "2579 Spartacus - contains a significant portion of olivine, which may
>>> indicate
>>> origin deeper within Vesta than other V-types."
>>> See list at:
>>> <http://en.wikipedia.org/wiki/V-type_asteroid>
>>> <http://en.wikipedia.org/wiki/4_Vesta>
>>>
>>> Pallas and its family of asteroids is certainly a candidate for one of
>>> the
>>> Carbonaceous parent body, even thought it shows no major excavations.
>>> "2 Pallas is a large and most certainly differentiated body but lacks
>>> evidence
>>> of a deep
>>> excavation and its spectrum shows carbonaceous chondrite affinities.
>>> However
>>> 75% of the astrtoids out there whose spectra we've measured fall in
>>> the C or
>>> Carbonaceous class."
>>> <http://en.wikipedia.org/wiki/2_Pallas>
>>> <http://en.wikipedia.org/wiki/Carbonaceous_chondrite>
>>> Also in my reading there is good indication that the Martian moons are
>>> captured
>>> carbonaceous asteroids
>>> <http://en.wikipedia.org/wiki/Moons_of_Mars>
>>>
>>> Asteroid types More than I can retain in my head:
>>> <http://nineplanets.org/asteroids.html>
>>> <http://en.wikipedia.org/wiki/Asteroid_spectral_types>
>>> * C-type, includes more than 75% of known asteroids: extremely
>>> dark
>>> (albedo 0.03); similar to carbonaceous chondrite meteorites;
>>> approximately the same chemical composition as the Sun minus hydrogen,
>>> helium
>>> and other volatiles;
>>>
>>> * S-type, 17%: relatively bright (albedo .10-.22); metallic
>>> nickel-iron
>>> mixed with iron- and magnesium-silicates;
>>>
>>> * M-type, most of the rest: bright (albedo .10-.18); pure
>>> nickel-iron.
>>> * There are also a dozen or so other rare types.
>>>
>>> Read more about Asteroids l Asteroid facts, pictures and information
>>> by
>>> nineplanets.org * C-type, includes more than 75% of known asteroids:
>>> extremely dark (albedo 0.03); similar to carbonaceous chondrite
>>> meteorites; approximately the same chemical composition as the
>>> Sun minus
>>> hydrogen, helium and other volatiles;
>>>
>>> * S-type, 17%: relatively bright (albedo .10-.22); metallic
>>> nickel-iron
>>> mixed with iron- and magnesium-silicates;
>>>
>>> * M-type, most of the rest: bright (albedo .10-.18); pure
>>> nickel-iron.
>>> * There are also a dozen or so other rare types.
>>>
>>> Read more about Asteroids l Asteroid facts, pictures and information
>>> by
>>> nineplanets.org
>>>
>>> Meteorites and their Parent Bodies 2nd Edition. Harry Mc Sween which I
>>> think us
>>> a google book online.
>>>
>>> Elton
>>>
>>>
>>>
>>> ----- Original Message ----
>>>> From: Richard Montgomery <rickmont at earthlink.net>
>>>> To: Ron Baalke <baalke at zagami.jpl.nasa.gov>; Meteorite Mailing List
>>>><meteorite-list at meteoritecentral.com>
>>>> Sent: Wed, April 13, 2011 8:39:46 PM
>>>> Subject: Re: [meteorite-list] Cold Asteroids May Have A Soft Heart
>>>>(AllendeMeteorite)
>>>>
>>>> Ron and List,
>>>>
>>>> This new evidence fits exactly into the recent question I posted,
>>>> 'Vesta,
>>>> for sure?'
>>>>
>>>> I only heard back from Elton (thanks, sincerely!) and yet now with
>>>> this
>>>> hypothesis, my question lingers as to the absolute recognition of
>>>> parent
>>>> bodies, with my query as to the yet-undiscovered potential pairings
>>>> of
>>>> undiscovered asteroids.
>>>>
>>>> MEM pointed out that the largest asteroids (aka Vesta etal) have
>>>> already
>>>> been located, with tell-tale impact and reflective signatures that
>>>> rule out
>>>> other parents for our HEDs.
>>>>
>>>> My new question, neophyte layman as I am, is:
>>>>
>>>> Does this new data/theory bring my initial question about
>>>> Vesta-for-sure-as-parent-for-HEDs back into play?
>>>>
>>>> -Richard Montgomery
>>>>
>>> ______________________________________________
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>>>
>>
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>
>
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Received on Sat 16 Apr 2011 10:43:28 PM PDT


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