AAS223

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AAS223

Post by Lazarus on 3rd January 2014, 1:28 pm

Thought it might be worth having a thread for this.

223rd AAS Meeting

There are some interesting topics in the list of abstracts.
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Re: AAS223

Post by Led_Zep on 6th January 2014, 5:14 pm

http://spaceref.com/exoplanets/newfound-planet-is-earth-mass-but-gassyan-international-team-of-astronomers-has-discovered-the-first.html

An international team of astronomers has discovered the first Earth-mass planet that transits, or crosses in front of, its host star. KOI-314c is the lightest planet to have both its mass and physical size measured

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Re: AAS223

Post by Led_Zep on 6th January 2014, 5:19 pm

http://spaceref.com/extrasolar-planets/kepler-provides-insight-about-enigmatic-but-ubiquitous-planets.html

« …More than three-quarters of the planet candidates discovered by NASA's Kepler spacecraft have sizes ranging from that of Earth to that of Neptune, which is nearly four times as big as Earth.
Such planets dominate the galactic census but are not represented in our own solar system. Astronomers don't know how they form or if they are made of rock, water or gas.

The Kepler team today reports on four years of ground-based follow-up observations targeting Kepler's exoplanet systems at the American Astronomical Society meeting in Washington. These observations confirm the numerous Kepler discoveries are indeed planets and yield mass measurements of these enigmatic worlds that vary between Earth and Neptune in size.

Included in the findings are five new rocky planets ranging in size from ten to eighty percent larger than Earth. Two of the new rocky worlds, dubbed Kepler-99b and Kepler-406b, are both forty percent larger in size than Earth and have a density similar to lead. The planets orbit their host stars in less than five and three days respectively, making these worlds too hot for life as we know it…. »
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Re: AAS223

Post by Led_Zep on 7th January 2014, 5:18 am


http://www.spacedaily.com/reports/Earth_appears_to_be_an_oddity_astronomers_say_999.html

Earth appears to be an oddity, astronomers say

"Our solar system seems to be different. All these planets that Kepler has found, they are strange," said Yoram Lithwick of Northwestern University.
"Twenty to 30 percent of all stars have these crazy planets."
Super-Earths and mini-Neptunes that are more than two and a half times the radius of Earth "must be covered with lots and lots of gas, which is the most surprising result," said Lithwick.
He studied about 60 such planets and found that they likely formed "very quickly after the birth of their star, while there was still a gaseous disk around the star."
"By contrast, Earth is thought to have formed much later, after the gas disk disappeared," he said.

(…)

At the conference, astronomers announced 70 new planet confirmations, 16 mass determinations from Doppler follow-up observations and five new rocky planets
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Re: AAS223

Post by PlutonianEmpire on 7th January 2014, 2:48 pm

More support for the Rare Earth Theory, then. Sad 

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Re: AAS223

Post by Lazarus on 7th January 2014, 4:20 pm

Included in the findings are five new rocky planets ranging in size from ten to eighty percent larger than Earth. Two of the new rocky worlds, dubbed Kepler-99b and Kepler-406b, are both forty percent larger in size than Earth and have a density similar to lead. The planets orbit their host stars in less than five and three days respectively, making these worlds too hot for life as we know it.
Ok so Kepler-99b and Kepler-406b are in short-period orbits, what about the other three? Are there any long-period extrasolar terrestrials yet? (I.e. that have measured densities)
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Re: AAS223

Post by Shellface on 7th January 2014, 7:40 pm

I think you might be misinterpreting that text, Lazarus; it seems to be pointing out that those two are exceptionally high density (lead has a density of 11 g/cm3, so with radii of 1.4 R the two planets should be about 6 M), while the other three must be lower density, probably closer to silicate (~6 g/cm3). HIRES also likely isn't too capable of detecting longer-period terrestrials around such faint stars.

Do you think the work being discussed is the same as the one discussed here (on-forum here) from last year? KOI-305.01 and KOI-321.01 are reasonably good matches in period, radius and density for Kepler-99b and Kepler-406b, respectively. The latter is interesting as it is in a system of three planets, with two ~Earth radius planets and a non-transiting Neptune.

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Re: AAS223

Post by Edasich on 8th January 2014, 6:07 am

Shellface wrote:I think you might be misinterpreting that text, Lazarus; it seems to be pointing out that those two are exceptionally high density (lead has a density of 11 g/cm3, so with radii of 1.4 R the two planets should be about 6 M), while the other three must be lower density, probably closer to silicate (~6 g/cm3). HIRES also likely isn't too capable of detecting longer-period terrestrials around such faint stars.

Do you think the work being discussed is the same as the one discussed here (on-forum here) from last year? KOI-305.01 and KOI-321.01 are reasonably good matches in period, radius and density for Kepler-99b and Kepler-406b, respectively. The latter is interesting as it is in a system of three planets, with two ~Earth radius planets and a non-transiting Neptune.

As in http://astro.berkeley.edu/~gmarcy/22kois.pdf :

KOI-305 b=Kepler-99 b
KOI-321 b=Kepler-406 b

Exactement, Poirot would say.
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