Kepler-11 : A compact six-planet system with mini-Neptunes

Sirius_Alpha wrote:

NASA To Announce New Planetary Discoveries
WASHINGTON -- NASA will host a news briefing at 1 p.m. EST, Wednesday, Feb. 2, to announce the Kepler mission's latest findings about planets outside our solar system. The briefing will be held in the NASA Headquarters auditorium at 300 E St S.W. in Washington and carried live on NASA Television and the agency's website at http://www.nasa.gov/ntv.

http://keplergo.arc.nasa.gov/

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Public Release of Q2 data (6:00 AM Feb 2, 2011 UTC)

At more than 11 hours before the official press conference?

According to the announcement, the data will be released today (Feb 1), and the news conference about the confirmed candidates will be tomorrow (Feb 2).

Gives you a chance to figure out what the announcement is before they announce it. Perhaps.

I cant wait

http://www.1310news.com/news/world/article/177773--nasa-telescope-sees-that-smaller-planets-more-common-than-giants-in-cosmos-good-news-for-life

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NASA released new data Wednesday from its Kepler telescope on more than 1,000 possible new planets outside our solar system — more than doubling the count of what astronomers call exoplanets. They haven't been confirmed as planets yet, but some astronomers estimate that 90 per cent of what Kepler has found will eventually be verified.

Where?

http://www.nasa.gov/mission_pages/kepler/main/index.html

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Kepler Data Release
Kepler Q1 data has been released and Kepler Q2 data will released at 1 a.m. EST on Feb. 2, 2011, and posted to http://archive.stsci.edu/kepler/.

It is up on the NASA homepage.

This is very good.

Kepler-11 discovery paper preprint is up on EPE.

HD 10180 has been surpassed. It's strange the mass of the outermost planet. Maybe poorly constrained?

Edasich wrote:

It's strange the mass of the outermost planet. Maybe poorly constrained?

Indeed. Looking at the paper, there's a few RV observations. I'm not sure if the < 0.95 M_J constraint comes from RV or TTV measurements.

The other masses are from transit timing variations caused by mutual interactions. The outermost planet is too far away from the others to cause strong enough perturbations.

Kepler-11f is a nice one: 2.3 Earth masses with a density of 0.7 g/cc. We are finding mini-Neptunes, where are the super-Earths?

Perhaps most planets the size of Earth end up as mini-Neptunes, and it is only due to their respective giant impact events stripping off their primordial atmospheres that Earth and Venus ended up as terrestrial planets?

So Earth-sized terrestrial planets would be a lot rarer than currently expected, while Earth sized mini-Neptunes are common. This could at least partly explain the Fermi paradox.

We should find out if this is the case fairly soon, once a sufficiently large number of Kepler planets have had their masses determined.

Sorry but I was little bit excited.I completely agree with Mongo and I am worry that all super earths are really mini neptunes.Densities definitely indicates that and seems to be earth and venus could have initial composition like planets d,e,f around kepler 11-I hope that this system is not common (I mean densities)

Actually on thinking about it, I may have to retract my comments about Alpha Centauri possibly being a bad bet for habitable planets due to probably limited supplies of water in the protoplanetary discs around A and B. This might in fact be a good thing...

Lazarus wrote:

Actually on thinking about it, I may have to retract my comments about Alpha Centauri possibly being a bad bet for habitable planets due to probably limited supplies of water in the protoplanetary discs around A and B. This might in fact be a good thing...

That's an interesting way to look at it.
But I would figure these planets at Kepler-11 migrated in from further out, where they could have easily accumulated water.

I've been thinking about it some more. What if systems like Kepler-9, possibly HD 10180 and others represent a set of systems characterised by several cores forming beyond the ice line and spiriling in producing the groups of (mini-)Neptunes we see today. This would be separate from the set of systems, like our Solar system, where terrestrial planet formation occurs as normal within a few AU of the star, without a marching horde of (mini-)ice giants storming through.

As to where all the super-Earths are, maybe real super-Earths and terrestrial planets don't really form in the kinds of systems we're finding, and don't experience significant inward migration, staying out away from the star like Mercury, Venus, Earth and Mars. As such, they would be longer period planets than what we're finding, and thus the observational bias would be against them.

I hope all planets in kepler 11 system gathered plenty light elements during formation and initial disc contained high amount of water.We see soon when next kepler planets not very close host star will be confirmed with mass what is going on.Possible is that all planets create with some h/he water elements and even planet candidate with radius like mars can contain some h/he,water.Hopefully not but if something happened in our solar system

Still I think about kepler 11 system.Does anybody knows planet b,c are enough far away from star to avoid any significant mass loss from stellar radiation?Densities other planets in this system are very low so unpatiently await for confirmation some other kepler candidates far away from their stars like kepler 10c and other.Hopefully it will answer whether super earths are mainly minineptunes or kepler 11 is unique and gathered only light elements

Kepler-11 b and c are close enough to have experienced some mass loss.

I'm guessing what Kepler is finding represents a type of planetary system characterised by multiple cores accreting envelopes and migrating inward, producing a packed cluster of mini-Neptunes close to the star. Our solar system would be an example where this did not occur, but instead there was not significant inward migration of any of the forming planets, allowing for terrestrial planet formation to proceed undisturbed.

Well it does look like these low-mass, low-density planets form around a wide range of stars: GJ 1214b orbits a 0.15 solar mases M-dwarf, while Kepler-11 is a G-type star.

Hopefully some genuine terrestrial planets in long-period orbits will show up at some point.

A dynamical analysis of the Kepler-11 planetary system
http://arxiv.org/abs/1205.0822

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The Kepler-11 star hosts at least six transiting super-Earth planets detected through the precision photometric observations of the KEPLER mission (Lissauer et al.). In this paper, we re-analyze the available KEPLER data, using the direct N-body approach rather than an indirect TTV method in the discovery paper. The orbital modeling in the realm of the direct approach relies on the whole data set, rather than the times of mid-transits only. Most of the results in the original paper are confirmed and extended. We constrained the mass of the outermost planet g to less than 30 Earth masses. The mutual inclinations between orbits b and c as well as between orbits d and e are determined with a good precision, in the range of [1,5] degrees. Having several solutions to four qualitative orbital models of the Kepler-11 system, we analyze its global dynamics with the help of dynamical maps. They reveal very complex structure of the phase space with narrow regions of regular motion. The dynamics are governed by a dense net of three- and four-body mean motion resonances, forming the Arnold web. Overlapping of these resonances is a main source of instability. We found that the Kepler-11 system may be long-term stable only in particular multiple resonant configurations with small relative inclinations. The mass-radius data derived for all companions reveal a clear anti-correlation between the mean density of the planets with their distance from the star. It may reflect the formation and early evolution history of the system.

The mass of planet f since beginning seemed to me underestimated

Wow, some of those models have very high mutual inclinations, even including the stable model II solutions (IIa, IIb). Note that solution IIb has planet g orbiting at 90 degrees to the rest of the system! Of the stable solutions, IVa (where Ω is constrained to be 0 for all planets) looks most plausible to me, otherwise you are relying on the low probability of multiple highly-aligned subgroups happening to line up along the line of sight so they all look transiting.

I suspect if we can manage to detect mutual transits, the mutual inclinations of the two involved planets can be estimated and shed some light on the true mutual inclinations in the system.