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

http://arxiv.org/abs/1303.0227

All Six Planets Known to Orbit Kepler-11 Have Low Densities

Strange and slightly suspicious as planet c is now 4.5 times lighter .Previous estimates seems much closer to be truth.All new data only confirm my opinion the least dense minineptunes of all known

Led_Zep wrote:

http://arxiv.org/abs/1303.0227

All Six Planets Known to Orbit Kepler-11 Have Low Densities

That's gross, planets c, e, f are more sort of mini-Saturn that mini-Neptune. Maybe the system had very little metals available during planets formation - but the host star, though old, seems to be of solar-like metallicity.

Phase Curves of the Kepler-11 Multi-Planet System
http://arxiv.org/abs/1404.7538

Quote :

The Kepler mission has allowed the detection of numerous multi-planet exosystems where the planetary orbits are relatively compact. The first such system detected was Kepler-11 which has six known planets at the present time. These kinds of systems offer unique opportunities to study constraints on planetary albedos by taking advantage of both the precision timing and photometry provided by Kepler data to monitor possible phase variations. Here we present a case study of the Kepler-11 system in which we investigate the phase modulation of the system as the planets orbit the host star. We provide predictions of maximum phase modulation where the planets are simultaneously close to superior conjunction. We use corrected Kepler data for Q1-Q17 to determine the significance of these phase peaks. We find that data quarters where maximum phase peaks occur are better fit by a phase model than a "null hypothesis" model.

(I've also extracted the Kepler-11 -related posts from the original main Kepler news and results thread.

I searched some data of kepler confirmed planets and Hadden gives parameters
Kepler 11 b mass 4.3 radius 1.71
Kepler 11 c mass 5.9 radius 2.73
Kepler 11 d mass 6.7 radius 2.97
Kepler 11 e mass 7.0 radius 3.98
Kepler 11 f mass 2.5 radius 2.37
Kepler 32 b mass 9.4 radius 2.25
Kepler 32 c mass 7.7 radius 2.02

??

http://kepler.nasa.gov/Mission/discoveries/

Could you be more explicit?

Data from Hadden are from 2014 seems to be more updated .It does not change low density nature of c-f planets

Kepler-11 is a Solar Twin: Revising the Masses and Radii of Benchmark Planets Via Precise Stellar Characterization
https://arxiv.org/abs/1611.06239

Quote :

The six planets of the Kepler-11 system are the archetypal example of a population of surprisingly low-density transiting planets revealed by the Kepler mission. We have determined the fundamental parameters and chemical composition of the Kepler-11 host star to unprecedented precision using an extremely high quality spectrum from Keck-HIRES (R≃67,000, S/N per pixel≃260 at 600 nm). Contrary to previously published results, our spectroscopic constraints indicate that Kepler-11 is a young main-sequence solar twin. The revised stellar parameters raise the densities of the Kepler-11 planets by about 30%, making them more typical of the emerging class of "puffy" close-in exoplanets. We obtain photospheric abundances of 22 elements and find that Kepler-11 has an abundance pattern similar to that of the Sun with a slightly higher overall metallicity. We additionally analyze the Kepler lightcurves using a photodynamical model and discuss the tension between spectroscopic and transit/TTV-based stellar density estimates.