Kepler News and Results (Thread 2)

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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 14th May 2018, 3:26 pm

Do you like phase curves? If so, here's some good news!

Kipping, Sandford & Janesen "Two Thousand Kepler Phase Curves from Phasma"
https://arxiv.org/abs/1805.04121

Gallery is here.
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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 24th May 2018, 2:04 pm

Kepler-503 turns out to be a subgiant rather than a solar-type dwarf star as previously thought. The companion Kepler-503b is at the hydrogen-burning limit.

Cañas et al. "Kepler-503b: An Object at the Hydrogen Burning Mass Limit Orbiting a Subgiant Star"
https://arxiv.org/abs/1805.08820
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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 13th June 2018, 9:09 pm

Update on the exomoon candidate at Kepler-1625b (do we not have a thread for this?)

Reanalysis of data favors the planet-moon model over the single-planet, but the significance of the evidence depends pretty strongly on how you detrend the data. The evidence is not convincing enough at this point to positively claim a detection, though this could be remedied with more data.

Revisiting the exomoon candidate signal around Kepler-1625b
https://arxiv.org/abs/1806.04672

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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 14th June 2018, 5:48 pm

Sirius_Alpha wrote:Update on the exomoon candidate at Kepler-1625b (do we not have a thread for this?)

Reanalysis of data favors the planet-moon model over the single-planet, but the significance of the evidence depends pretty strongly on how you detrend the data. The evidence is not convincing enough at this point to positively claim a detection, though this could be remedied with more data.

Revisiting the exomoon candidate signal around Kepler-1625b
https://arxiv.org/abs/1806.04672
David Kipping posted a response on Twitter here

Will be interesting to see what the HST data brings to this.
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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 2nd July 2018, 9:00 pm

The orbital eccentricity of small planet systems
https://arxiv.org/abs/1807.00549

We determine the orbital eccentricities of individual small Kepler planets, through a combination of asteroseismology and transit light-curve analysis. We are able to constrain the eccentricities of 51 systems with a single transiting planet, which supplement our previous measurements of 66 planets in multi-planet systems. Through a Bayesian hierarchical analysis, we find evidence that systems with only one detected transiting planet have a different eccentricity distribution than systems with multiple detected transiting planets. The eccentricity distribution of the single-transiting systems is well described by the positive half of a zero-mean Gaussian distribution with a dispersion σe=0.32±0.06, while the multiple-transit systems are consistent with σe=0.083+0.015−0.020. A mixture model suggests a fraction of 0.76+0.21−0.12 of single-transiting systems have a moderate eccentricity, represented by a Rayleigh distribution that peaks at 0.26+0.04−0.06. This finding may reflect differences in the formation pathways of systems with different numbers of transiting planets. We investigate the possibility that eccentricities are "self-excited" in closely packed planetary systems, as well as the influence of long-period giant companion planets. We find that both mechanisms can qualitatively explain the observations. We do not find any evidence for a correlation between eccentricity and stellar metallicity, as has been seen for giant planets. Neither do we find any evidence that orbital eccentricity is linked to the detection of a companion star. Along with this paper we make available all of the parameters and uncertainties in the eccentricity distributions, as well as the properties of individual systems, for use in future studies.

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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 8th July 2018, 8:43 pm

TTV-determined Masses for Warm Jupiters and their Close Planetary Companions
https://arxiv.org/abs/1807.02217

Although the formation and the properties of hot Jupiters (with orbital periods P<10d) have attracted a great deal of attention, the origins of warm Jupiters (10<P<100d) are less well-studied. Using a transit timing analysis, we present the orbital parameters of five planetary systems containing warm Jupiters, Kepler 30, Kepler 117, Kepler 302, Kepler 487 and Kepler 418. Three of them, Kepler-30 c(Mp=549.4±5.6M⊕), Kepler-117 c(Mp=702±63M⊕) and Kepler 302 c(Mp=933±527M⊕), are confirmed to be real warm Jupiters based on their mass. Insights drawn from the radius-temperature relationship lead to the inference that hot Jupiters and warm Jupiters can be roughly separated by Teff,c=1123.7±3.3 K. Also, Teff,c provides a good separation for Jupiters with companion fraction consistent with zero(Teff>Teff,c) and those with companion fraction significantly different from zero (Teff<Teff,c).

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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 12th September 2018, 4:02 pm

I don't think this one's hit the arXiv so far...

Brady et al. (2018) "Kepler-1656b: A Dense Sub-Saturn with an Extreme Eccentricity"
http://iopscience.iop.org/article/10.3847/1538-3881/aad773/meta

32-day orbital period, eccentricity 0.84
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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 24th September 2018, 9:26 pm

Now on arXiv.

Kepler-1656b: a Dense Sub-Saturn With an Extreme Eccentricity
https://arxiv.org/abs/1809.08436


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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 30th September 2018, 8:36 pm

Transit Timing Variations and linear ephemerides of confirmed Kepler transiting exoplanets
https://arxiv.org/abs/1809.11104

We determined new linear ephemerides of transiting exoplanets using long-cadence de-trended data from quarters Q1 to Q17 of Kepler mission. We analysed TTV diagrams of 2098 extrasolar planets. The TTVs of 121 objects were excluded (because of insufficient data-points, influence of stellar activity, etc). Finally, new linear ephemerides of 1977 exoplanets from Kepler archive are presented. The significant linear trend was observed on TTV diagrams of approximately 35% of studied exoplanets. Knowing correct linear ephemeris is principal for successful follow-up observations of transits. Residual TTV diagrams of 64 analysed exoplanets shows periodic variation, 43 of these TTV planets were not reported yet.
It looks like all 43 of these involve confirmed planets already.

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Re: Kepler News and Results (Thread 2)

Post by Daniel on 4th October 2018, 3:49 pm

I just wonder if this exoplanet planet candidate will be ever confirmed,the binary stellar parameters look quite interesting the stars it's seems A+M binary with a planet.

Modelling the circumbinary candidate KOI-1741

https://warwick.ac.uk/fac/sci/physics/research/astro/people/jamesblake/urss_poster_2016_jb.pdf
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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 4th October 2018, 4:08 pm

Good spot there, would be interesting to figure out what the view would be like from the planet - should be quite a colour contrast between the two stars but maybe the red dwarf would be lost in the glare.

Talking of unconfirmed circumbinary planets, whatever happened to Kepler-47d? There's also the unconfirmed planet in the KIC 7177553 quadruple system.
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Re: Kepler News and Results (Thread 2)

Post by Daniel on 4th October 2018, 5:46 pm

Lazarus wrote:Good spot there, would be interesting to figure out what the view would be like from the planet - should be quite a colour contrast between the two stars but maybe the red dwarf would be lost in the glare.

Talking of unconfirmed circumbinary planets, whatever happened to Kepler-47d? There's also the unconfirmed planet in the KIC 7177553 quadruple system.

There is also KOI 2938 = KID 7821010 that would be the first non-transiting CBP detected by Kepler mission around F+F dwarf stars far as I known never been published.

https://www.astro.up.pt/investigacao/conferencias/toe2014/files/wwelsh.pdf
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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 15th October 2018, 8:40 pm

A New Planet in the Kepler-159 System From Transit Timing Variations
https://arxiv.org/abs/1810.06486

The Kepler Space Telescope has discovered thousands of planets via the transit method. The transit timing variations of these planets allows us not only to infer the existence of other planets, transiting or not, but to characterize a number of parameters of the system. Using the transit timing variations of the planets Kepler-159b and 159c, the transit simulator TTVFast, and the Bayesian Inference tool MultiNest, we predict a new non-transiting planet, Kepler-159d, in a resonant 2:1 orbit with Kepler-159c. This configuration is dynamically stable on at least 10 Myr time scales, though we note that other less stable, higher-order resonances could also produce similar TTVs during the three-year window Kepler was in operation.

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Re: Kepler News and Results (Thread 2)

Post by Sirius_Alpha on 30th October 2018, 11:46 am

Uh oh..

NASA to Hold Media Call on Status of Kepler Space Telescope Today
https://www.nasa.gov/press-release/nasa-to-hold-media-call-on-status-of-kepler-space-telescope-today

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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 30th October 2018, 3:04 pm

"Uh oh" was right.

Kepler has run out of fuel, the science mission is over and the spacecraft has been retired.

https://www.jpl.nasa.gov/news/news.php?feature=7272
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Re: Kepler News and Results (Thread 2)

Post by Led_Zep on 30th October 2018, 3:22 pm

pale Sad
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Re: Kepler News and Results (Thread 2)

Post by Lazarus on 31st October 2018, 3:55 am

Kepler/K2 is dead, long live Kepler/K2!

Barentsen et al. "Kepler's Discoveries Will Continue: 21 Important Scientific Opportunities with Kepler & K2 Archive Data"
https://arxiv.org/abs/1810.12554
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