Kepler-36: A Pair of Planets with Neighboring Orbits and Dissimilar Densities

Carter, Joshua A.; Agol, Eric; Chaplin, W. J.; Basu, Sarbani; Bedding, Timothy R.; Buchhave, Lars A.; Christensen‐Dalsgaard, J.; Deck, Katherine M.; Elsworth, Y.; Fabrycky, Daniel C.; Ford, Eric B.; Fortney, Jonathan J.; Hale, Steven J.; Handberg, R.; Hekker, S.; Holman, Matthew J.; Huber, Daniel; Karoff, C.; Kawaler, S. D.; Kjeldsen, H.; Lissauer, Jack J.; Lopez, Eric; Lund, M. N.; Lundkvist, M.; Metcalfe, T. S.; Miglio, A.; Rogers, Leslie; Stello, Dennis; Borucki, W. J.; Bryson, Steve; Christiansen, Jessie L.; Cochran, William D.; Geary, John C.; Gilliland, Ronald L.; Haas, Michael R.; Hall, Jennifer R.; Howard, Andrew W.; Jenkins, Jon M.; Klaus, Todd C.; Koch, David; Latham, David W.; MacQueen, Phillip J.; Sasselov, Dimitar; Steffen, Jason H.; Twicken, Joseph D.; Winn, Joshua N.

doi:10.1126/science.1223269

Cited by 387 publications

(331 citation statements)

References 85 publications

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“…Correcting for the lower equilibrium temperature of Kepler-87 c (T eq = 403.3), its envelope mass fraction is probably even higher than that. Planets such as Kepler-87 c, as well as the highly irradiated Kepler-11 and -36 systems Carter et al 2012), demonstrate that the great compositional variety that was found for gas giants also extends down to planets with intermediate masses between Earth and Uranus.…”

Section: Discussionmentioning

confidence: 99%

An independent planet search in theKeplerdataset

Ofir

Dreizler

Zechmeister

et al. 2014

A&A

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Context. The primary goal of the Kepler mission is the measurement of the frequency of Earth-like planets around Sun-like stars. However, the confirmation of the smallest of Kepler's candidates in long periods around FGK dwarfs is extremely difficult or even beyond the limit of current radial velocity technology. Transit timing variations (TTVs) may offer the possibility for these confirmations of near-resonant multiple systems by the mutual gravitational interaction of the planets. Aims. We previously detected the second planet candidate in the KOI 1574 system. The two candidates have relatively long periods (about 114 d and 191 d) and are in 5:3 resonance. We therefore searched for TTVs in this particularly promising system. Methods. The full Kepler data was detrended with the proven SARS pipeline. The entire data allowed one to search for TTVs of the above signals, and to search for additional transit-like signals.Results. We detected strong anti-correlated TTVs of the 114 d and 191 d signals, dynamically confirming them as members of the same system. Dynamical simulations reproducing the observed TTVs allowed us to also determine the masses of the planets. We found KOI 1574.01 (hereafter Kepler-87 b) to have a radius of 13.49 ± 0.55 R ⊕ and a mass of 324.2 ± 8.8 M ⊕ , and KOI 1574.02 (Kepler-87 c) to have a radius of 6.14 ± 0.29 R ⊕ and a mass of 6.4 ± 0.8 M ⊕ . Both planets have low densities of 0.729 and 0.152 g cm −3 , respectively, which is non-trivial for such cold and old (7−8 Gyr) planets. Specifically, Kepler-87 c is the lowest-density planet in the super-Earth mass range. Both planets are thus particularly amenable to modeling and planetary structure studies, and also present an interesting case where ground-based photometric follow-up of Kepler planets is very desirable. Finally, we also detected two more short-period super-Earth sized (<2 R ⊕ ) planetary candidates in the system, making the relatively high multiplicity of this system notable against the general paucity of multiple systems in the presence of giant planets like Kepler-87 b.

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Section: Discussionmentioning

confidence: 99%

An independent planet search in theKeplerdataset

Ofir

Dreizler

Zechmeister

et al. 2014

A&A

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“…On the very last day of working on this paper, the KOI 277 system with its two planets and their associated TTVs, was published by the Kepler team as confirmed and was designated Kepler-36 (Carter et al 2012). While our analysis is an independent discovery and confirmation of this system, Carter et al (2012) used a Newtonian model -this system is obviously nonKeplerian -and thus their analysis is more accurate.…”

Section: Koi 277 -An Exceptionally Strong Candidatementioning

confidence: 99%

“…While our analysis is an independent discovery and confirmation of this system, Carter et al (2012) used a Newtonian model -this system is obviously nonKeplerian -and thus their analysis is more accurate.…”

Section: Koi 277 -An Exceptionally Strong Candidatementioning

confidence: 99%

An independent planet search in theKeplerdataset

Ofir

Dreizler

2013

A&A

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Aims. We present first results of our efforts to re-analyze the Kepler photometric dataset, searching for planetary transits using an alternative processing pipeline to the one used by the Kepler mission Methods. The SARS pipeline was tried and tested extensively by processing all available CoRoT mission data. For this first paper of the series we used this pipeline to search for (additional) planetary transits only in a small subset of stars -the Kepler objects of interest (KOIs), which are already known to include at least one promising planet candidate. Results. Although less than 1% of the Kepler dataset are KOIs we are able to significantly update the overall statistics of planetary multiplicity: we find 84 new transit signals on 64 systems on these light curves (LCs) only, nearly doubling the number of transit signals in these systems. Forty-one of the systems were singly-transiting systems that are now multiply-transiting. This significantly reduces the chances of false positive in them. Notable among the new discoveries are KOI 435 as a new six-candidate system (of which kind only Kepler-11 was known before), KOI 277 (which includes two candidates in a 6:7 period commensurability that has anti-correlated transit timing variations) -all but validating the system, KOIs 719, 1574, and 1871 that have small planet candidates (1.15, 2.05 and 1.71 R ⊕ ) in the habitable zone of their host star, and KOI 1843 that exhibits the shortest period (4.25 h) and is among the smallest (0.63 R ⊕ ) of all planet candidates. We are also able to reject 11 KOIs as eclipsing binaries based on photometry alone, update the ephemeris for five KOIs and otherwise discuss a number of other objects, which brings the total of new signals and revised KOIs in this study to more than one hundred. Interestingly, a large fraction, about ∼1/3, of the newly detected candidates participate in period commensurabilities. Finally, we discuss the possible overestimation of parameter errors in the current list of KOIs and point out apparent problems in at least two of the parameters. Conclusions. Our results strengthen previous analyses of the multi-transiting ensemble, and again highlight the great importance of this dataset. Nevertheless, we conclude that despite the phenomenal success of the Kepler mission, parallel analysis of the data by multiple teams is required to make full use of the data.

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“…We therefore repeated the analysis after fixing the gravity of the models to this value. Such an approach is now routinely implemented in spectroscopic studies of seismic targets (e.g., Batalha et al 2011;Carter et al 2012;Thygesen et al 2012;Huber et al 2013) and is expected to provide more robust estimates of the physical parameters and ultimately chemical abundances. The temperature was also determined from Fe excitation balance.…”

Section: Determination Of Stellar Parametersmentioning

confidence: 99%

Atmospheric parameters and chemical properties of red giants in the CoRoT asteroseismology fields

Morel

Miglio

Lagarde

et al. 2014

A&A

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A precise characterisation of the red giants in the seismology fields of the CoRoT satellite is a prerequisite for further in-depth seismic modelling. High-resolution FEROS and HARPS spectra were obtained as part of the ground-based follow-up campaigns for 19 targets holding great asteroseismic potential. These data are used to accurately estimate their fundamental parameters and the abundances of 16 chemical species in a self-consistent manner. Some powerful probes of mixing are investigated (the Li and CNO abundances, as well as the carbon isotopic ratio in a few cases). The information provided by the spectroscopic and seismic data is combined to provide more accurate physical parameters and abundances. The stars in our sample follow the general abundance trends as a function of the metallicity observed in stars of the Galactic disk. After an allowance is made for the chemical evolution of the interstellar medium, the observational signature of internal mixing phenomena is revealed through the detection at the stellar surface of the products of the CN cycle. A contamination by NeNa-cycled material in the most massive stars is also discussed. With the asteroseismic constraints, these data will pave the way for a detailed theoretical investigation of the physical processes responsible for the transport of chemical elements in evolved, low-and intermediate-mass stars.

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Kepler-36: A Pair of Planets with Neighboring Orbits and Dissimilar Densities

Cited by 387 publications

References 85 publications

An independent planet search in theKeplerdataset

An independent planet search in theKeplerdataset

An independent planet search in theKeplerdataset

Atmospheric parameters and chemical properties of red giants in the CoRoT asteroseismology fields

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