[meteorite-list] Lutetia

From: MexicoDoug <mexicodoug_at_meteoritecentral.com>
Date: Sat, 12 Nov 2011 17:34:14 -0500 (EST)
Message-ID: <8CE6FA256EA6985-82C-2C196_at_webmail-d056.sysops.aol.com>

Hey Benjamin

Spectroscopy is one of many tools in the toolbox which unfortunately is
not a good toolbox until you can scoop up a sample and look at it.

This looks like you are responding to me since I mentioned paint in my
reply of the difficulty of interpreting convoulted spectra made of
billions of years of dust and collisions.

But I'm not really sure because I called it speculation; so whoever you
are talking about dismissing it, maybe they can speak up. An
astronomer doing chemical spectras has a light path through earth's
atmosphere, across space beyond Timbuctu to arrive at a sample that
hasn't been cleaned for a few billion years and has been subjected to
all varieties of meteoritical, asteroidal, cosmic particle, as well as
the normal alteration processes.

Then he has a collection of meteorites which is probably far from
complete, but he is lucky if by chance one of them fairly matches after
he does his best to cheat by starting with the meteorite fresh cut
spectrum assuming it is his best match and working his way backwards
doing what he can along the way to lower this peak or raise that one
and then when all the dust is cleared :-), he just shows his spectrum
of the asteroid and his spectrum of the meteorite after his series of
manipulations and says Eureka, I've found it!

The down side is minimal, the astronomer doesn't even get much of an
academic spanking and speculation is healthy and fun. If he happens to
be clever and lucky though, the upside is it really is a match and he
goes down as the guy who discovered the composition of an asteroid or
asteroid class.

In the case of Lutetia, a closer view from Rosetta was significant
becuase it eliminated many erroneous conclusions from other spectra of
it that had been taken from Earth distance and it confirmed there are
no organic materials, and water is scarce.

Basically, after gravitational measurements, a different tool than
spectroscopic ones is added, and it shows Lutetia is heave for its size
does the idea it has a lot of metal start sounding good. But to say it
is an E-meteorite class instead, for example of a Bencubbinite or
perhaps one of the many types of millions of asteroids that we have not
seen specimens from ... it's a real concrete jungle out there ...

So, speculative is the correct word to use. And after reviewing the
limitations of the spectroscopy, let's paint the town with it.

Most interesting to me was the very large crater found. Now, luckily
the Spectrum of Lutetia is rather unique. I the case of Vesta, the
scale fell in favore of it being understood as the HED source after a
chain of Vestoids was found spanning Vesta's orbit to a Kirkwood gap.
In the case of Lutetia, let's see if the 10 million kilometers it needs
to span have any baby Parisians along a path in an analolgous
manner...Verrrrrrrrry interrrresting, but ... not stupid!

Kindest wishes
Doug


-----Original Message-----
From: Benjamin P. Sun <bpsun2009 at gmail.com>
To: meteorite-list <meteorite-list at meteoritecentral.com>
Sent: Sat, Nov 12, 2011 3:32 pm
Subject: Re: [meteorite-list] Lutetia


Regolith is mostly powdered rock and pebbles from the parent body that
may or may not be compacted at the surface.
So why should the reflectance spectra from Lutetia's regolith be
totally dismissed? Are you dismissing Spectroscopy of asteroids
altogether?
If the "paint" derived from the parent body, then analysis of the
"paint" could possibly tell us something about the parent body itself.
Yes?
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Received on Sat 12 Nov 2011 05:34:14 PM PST