[meteorite-list] NWA5400

From: Jodie Reynolds <spacerocks_at_meteoritecentral.com>
Date: Mon, 11 Mar 2013 11:15:30 -0700
Message-ID: <852658746.20130311111530_at_spaceballoon.org>

Dear Professor Agee,

The IAU's decision to go all rogue on the definition of a "planet,
dwarf-planet, minor-planet, [iamnotaplanet, iamtooaplanet,
someplanetnamedstan]" doesn't leave me with a warm and fuzzy about
calling Earth a planet. "Cleared our orbit" - I'm not even certain
that's necessarily the case...

But then, having spent my formative years haunting Lowell
Observatory, I've got a dog in that fight and I'm pretty compromised
intellectually/emotionally on the whole topic.

I agree that today the IAU defines 4Vesta as a "minor planet" the
same as any other asteroid, though it's larger and with more of a
cleared orbit than Makemake or probably Haumea, both "dwarf planets"
per the IAU, and not far behind Ceres.

I'm not at all confident the IAU won't change their mind tomorrow** and
turn it into a "dwarf planet" with the same total lack of regard and
status as Pluto received.

--- Jodie

** 4Vesta appears to have far more hydrostatic equilibrium than
dwarf-planet Haumea, and it appears to have cleared its neighborhood more than any
of the other "Small Solar System Bodies" excepting Ceres, per Resolution 5A. Resolution 5B would have cleared
a lot of that up, but 5A was passed and 5B shot down, go figger, and
now we need to worry about "trans-Neptunian dwarf planets that aren't
planets at all but bear the name 'planet'" ;-)





Monday, March 11, 2013, 7:41:12 AM, you wrote:

> Hi Pete,

> Aubrites and enstatite chondrites also plot on the oxygen isotope
> terrestrial fractionation line (TFL) and up to now they are not proven
> to be from planets. So being on the TFL doesn't make the meteorite
> planetary. But I guess it depends on your definition of "planetaries",
> I would only put lunars and martians in that category, but not HEDs.
> Last time I checked, 4 Vesta the hypothesized HED parent body, was
> still an asteroid, not a planet. I see no reason to consider NWA 5400
> "planetary". On the other hand, if someone did an age-date on it, and
> it came up with a crystallization age much more recent than ~4.5 B.Y.,
> then things would get interesting. This is because asteroidal
> achondrites have ages ~4.5 B.Y., whereas planets tend to have younger
> basalts. Likewise, the search for meteorites from Mercury or Venus
> should include igneous crystallization ages as part of the "proof".

> Carl Agee

> Carl B. Agee
> Director and Curator, Institute of Meteoritics
> Professor, Earth and Planetary Sciences
> MSC03 2050
> University of New Mexico
> Albuquerque NM 87131-1126

> Tel: (505) 750-7172
> Fax: (505) 277-3577
> Email: agee at unm.edu
> http://meteorite.unm.edu/people/carl_agee/

> On Mon, Mar 11, 2013 at 2:20 AM,
> <pshugar at messengersfromthecosmos.com> wrote:
>> Since this tracks on the terestial O2 line, can this be concidered a
>> planetary meteorite, along
>> with the Lunars, Martians, as well as Asteroid 4 vesta?
>>
>> Would these be the only 4 planitaries so far or has maybe Mecrury
>> checked in with a sample of it's own?
>>
>> Pete IMCA 1733
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>>



> --

-- 
Best regards,
 Jodie                            mailto:spacerocks at spaceballoon.org

Received on Mon 11 Mar 2013 02:15:30 PM PDT