Larry, and interested Listees,
Thank you for the word straight from the
AAS horse's mouth!
For those interested, the Kepler-10 star is a
spectral type G star, with a mass of 0.895 ± 0.6
solar masses, a radius of 1.056 ± 0.021 times the
Sun's radius, a temperature of 5627 ± 44 K. The
metallicity of [Fe/H] is ?0.15 ± 0.04. It's an old
Population II star at 11.9 ± 4.5 billion years old.
That's really old.
the star it orbits (and thus the star
system) is iron poor relative to the Sun...
With a metallicity of -0.15, I make that out as
10^-0.15 = 0.708 of the Fe/H ratio of our Sun.
I wouldn't call that so iron-poor as to be below
the iron poverty line. For a star with 90% of the
mass of the Sun, it has more than enough iron
to whip up a few planets. That star may have had
to dig deeper into its pockets to create an iron
planet, but I think it could have it.
Of course, I will admit to a certain fondness for
an iron planet since I predicted them back during
the IAU Planet Fuss. There are only four things
you can make a planet out of: iron, rock, low-weight
volatiles ("gas") and high weight volatiles ("ice").
And we have a sample of all the possible planetary
types except the solid-iron-ball planet.
And... if you're really feeing fanciful, the surface
temperature of Kepler 10b is about 1600 C., or
hot enough to melt gold. How about a solid iron
planet with 12 billion-year-old impact basins and
long wrinkle-ridges of mountain ranges that are
lapped by vast and rolling oceans of molten gold,
with the mountainous tides of the close star
washing the gold seas over the landscape?
Now, that's an alien planet! Although I'll grant
you an ocean of molten aluminum is more likely
(but not as picturesque), or a blend of many heavy
metals.
It's worth mentioning that there is another
Kepler candidate around this star. It has not yet
been confirmed. 10c is planet orbiting at 0.24 AU
with a period of 45.3 days. It has a poorly
constrained mass (less than 20 Earth masses)
and a diameter of about 5000 km. We need to
get the seismic data from the star sorted out to
get a mass figure. I suspect that there are more
planetary signatures to be found from ground-
based observations.
Such an interesting universe!
Sterling K. Webb
----------------------------------------------------------------------
----- Original Message -----
From: <lebof...@lpl.arizona.edu>
To: "Sterling K. Webb" <sterling_k_w...@sbcglobal.net>
Cc: "Meteorite-list" <meteorite-list@meteoritecentral.com>
Sent: Monday, January 10, 2011 10:54 PM
Subject: Re: [meteorite-list] NASA's Kepler Mission Discovers Its First
RockyPlanet
Hi Everyone:
An update. Geoff Marcy gave an invited talk this evening at the
meeting I
am at (American Astronomical Society). The density of the "new" planet
is
8.8 +/_ 2.5 g/cc (iron meteorites are 7-8). The large uncertainty (not
bad
given the size of the object) implies that the planet can be anywhere
from
a more compressed "Earth" (similar composition, but denser due to
greater
mass) to an object made up of 75% iron (closer to Mercury in
composition).
I find that interesting given that the star it orbits (and thus the
star
system) is iron poor relative to the Sun. There is something new every
day!
Larry
This is the top item on a list of Kepler "hits" waiting
to be verified by ground-based telescopes. The list is
roughly 700 "hits" long and we can expect a minimum
of 500 to be confirmed.
There are more hits in the data being teased out,
so we can expect a flood of planets to be slowly confirmed
and dribbled out. Planet-O-Rama!
Sterling K. Webb
--------------------------------------------------------------------------
----- Original Message -----
From: "Meteorites USA" <e...@meteoritesusa.com>
To: "Meteorite-list" <meteorite-list@meteoritecentral.com>
Sent: Monday, January 10, 2011 1:28 PM
Subject: [meteorite-list] NASA's Kepler Mission Discovers Its First
RockyPlanet
http://www.jpl.nasa.gov/news/news.cfm?release=2011-007&cid=release_2011-007&msource=11007&tr=y&auid=7605855
Not in the habitable zone, and 20 times closer to the Kepler 10 star
than Mercury is to our Sun, but it is 1.4 times the size of Earth
which is the smallest planet ever discovered outside our solar
system.
Way cool!
Regards,
Eric
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