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Two TRULY Earth-sized exoplanets found
Posted: 20.12.2011, 23:52
by PlutonianEmpire
http://www.nasa.gov/mission_pages/keple ... ystem.htmlMOFFET FIELD, Calif. -- NASA's Kepler mission has discovered the first Earth-size planets orbiting a sun-like star outside our solar system. The planets, called Kepler-20e and Kepler-20f, are too close to their star to be in the so-called habitable zone where liquid water could exist on a planet's surface, but they are the smallest exoplanets ever confirmed around a star like our sun.
The discovery marks the next important milestone in the ultimate search for planets like Earth. The new planets are thought to be rocky. Kepler-20e is slightly smaller than Venus, measuring 0.87 times the radius of Earth. Kepler-20f is a bit larger than Earth, measuring 1.03 times its radius. Both planets reside in a five-planet system called Kepler-20, approximately 1,000 light-years away in the constellation Lyra.
Awesome!
Re: Two TRULY Earth-sized exoplanets found
Posted: 21.12.2011, 15:22
by selden
The formal publication about the planets is available at
http://www.nature.com/nature/journal/vn ... 10780.htmlA reasonable description of the possibilities is available in The Planetary Society Blog by Emily Lakdawalla at
http://www.planetary.org/blog/article/00003309/
Re: Two TRULY Earth-sized exoplanets found
Posted: 23.12.2011, 23:03
by Tegmine
Made an add-on of this last night. Unfortunately, without some further orbital parameters, here's how it all looks...
As you can see, there's some overlap between the orbits of b and e. Part of this is due to the uncertainty regarding the eccentricity of e. I've done no textures for it yet, so everything is blank.
But this is a very exciting discovery, despite the high temp of the planets...
-M-
Re: Two TRULY Earth-sized exoplanets found
Posted: 24.12.2011, 01:19
by Hungry4info
Why do your planets have eccentricities? As far as we know, all their orbits are circular. With no measurement of eccentricity (only constraints), a circular orbit is the default assumption.
Or were you going for a more fictional representation?
Re: Two TRULY Earth-sized exoplanets found
Posted: 24.12.2011, 13:34
by Tegmine
This sounds like a rather lame excuse, but I got it from the Kepler site. The stats on the planets seemed to point to some level of eccentricity.
Here's what the Discovery Tables on its website says...
http://kepler.nasa.gov/Mission/discoveries/I'm not trying to be argumentative. I made it this way based on the info given. If I flubbed up, then it can be fixed.
-M-
Re: Two TRULY Earth-sized exoplanets found
Posted: 24.12.2011, 21:36
by Hungry4info
The eccentricities given at the Kepler site are upper limits (hence the
less than sign). Essentially, you can work out constraints to the eccentricity based on stability arguments, or from radial velocity limits for those two planets that were detected. "The planet must have an eccentricity
less than n."
Tegmine wrote:I'm not trying to be argumentative.
I know; I apologise if I sounded that way.
Re: Two TRULY Earth-sized exoplanets found
Posted: 31.12.2011, 13:55
by Tegmine
Fixed. I left a little eccentricity, for some level of authenticity...
-M-
Re: Two TRULY Earth-sized exoplanets found
Posted: 11.01.2012, 07:53
by ajtribick
The Kepler-20 system is in the latest version of extrasolar.ssc/extrasolar.stc available from the Subversion repository (thanks Grant!)
Also another system which contains Earth-sized planets, KOI-55. The KOI-55 planets are probably the remnants of gas giants that were engulfed during the parent star's red giant phase.
Re: Two TRULY Earth-sized exoplanets found
Posted: 12.01.2012, 03:32
by PlutonianEmpire
ajtribick wrote:The Kepler-20 system is in the latest version of extrasolar.ssc/extrasolar.stc available from the Subversion repository (thanks Grant!)
Also another system which contains Earth-sized planets, KOI-55. The KOI-55 planets are probably the remnants of gas giants that were engulfed during the parent star's red giant phase.
I got goosebumps looking at both of these systems in Celestia....
We're so close, yet so far....
Re: Two TRULY Earth-sized exoplanets found
Posted: 13.01.2012, 04:32
by Tegmine
What about KOI-961...3 planets smaller than Earth. The largest is Mars-mass (give or take a smidge.)
-M-
Re: Two TRULY Earth-sized exoplanets found
Posted: 13.01.2012, 08:07
by ajtribick
Re: Two TRULY Earth-sized exoplanets found
Posted: 18.01.2012, 01:18
by PlutonianEmpire
ajtribick wrote:Also another system which contains Earth-sized planets, KOI-55. The KOI-55 planets are probably the remnants of gas giants that were engulfed during the parent star's red giant phase.
What do the "KOI" and "KIC" acronyms stand for, and what are their meanings?
Re: Two TRULY Earth-sized exoplanets found
Posted: 18.01.2012, 07:36
by ajtribick
KIC = Kepler Input Catalog
KOI = Kepler Object of Interest