Kepler News and Results (Thread 2)

Some new planet candidates...

Searching the Entirety of Kepler Data. I. 17 New Planet Candidates Including One Habitable Zone World
https://iopscience.iop.org/article/10.3847/1538-3881/ab6cf8

Quote :

We present the results of an independent search of all ~200,000 stars observed over the four year Kepler mission (Q1–Q17) for multiplanet systems, using a three-transit minimum detection criterion to search orbital periods up to hundreds of days. We incorporate both automated and manual triage, and provide estimates of the completeness and reliability of our vetting pipeline. Our search returned 17 planet candidates (PCs) in addition to thousands of known Kepler Objects of Interest (KOIs), with a 98.8% recovery rate of already confirmed planets. We highlight the discovery of one candidate, KIC-7340288 b, that is both rocky (radius $\leqslant 1.6{R}_{\oplus }$) and in the Habitable Zone (insolation between 0.25 and 2.2 times the Earth's insolation). Another candidate is an addition to the already known KOI-4509 system. We also present adaptive optics imaging follow-up for six of our new PCs, two of which reveal a line-of-sight stellar companion within 4''.

Edit: Now on arXiv! https://arxiv.org/abs/2003.04397

A Habitable-Zone Earth-Sized Planet Rescued from False Positive Status
https://arxiv.org/abs/2004.06725

Quote :

We report the discovery of an Earth-sized planet in the habitable zone of a low-mass star called Kepler-1649. The planet, Kepler-1649 c, is 1.06+0.15−0.10 times the size of Earth and transits its 0.1977 +/- 0.0051 Msun mid M-dwarf host star every 19.5 days. It receives 74 +/- 3 % the incident flux of Earth, giving it an equilibrium temperature of 234 +/- 20K and placing it firmly inside the circumstellar habitable zone. Kepler-1649 also hosts a previously-known inner planet that orbits every 8.7 days and is roughly equivalent to Venus in size and incident flux. Kepler-1649 c was originally classified as a false positive by the Kepler pipeline, but was rescued as part of a systematic visual inspection of all automatically dispositioned Kepler false positives. This discovery highlights the value of human inspection of planet candidates even as automated techniques improve, and hints that terrestrial planets around mid to late M-dwarfs may be more common than those around more massive stars.

Quote :

This discovery highlights the value of human inspection of planet candidates even as automated techniques improve, and hints that terrestrial planets around mid to late M-dwarfs may be more common than those around more massive stars.

The apparent increased frequency of "habitable zone" terrestrials around low-mass stars is an interesting result. They should therefore be by far the most common types of "HZ" terrestrials in the galaxy, yet here we are sitting on a planet around an early G-type star.

The Copernican principle does not give me cause for optimism about the habitability of such worlds.

http://www.keckobservatory.org/kepler-88/

Newly Discovered Exoplanet Dethrones Former King Of Kepler-88 Planetary System

A team of astronomers led by the University of Hawaiʻi Institute for Astronomy (UH IfA) has discovered a planet three times the mass of Jupiter in a distant planetary system.

The discovery is based on six years of data taken at W. M. Keck Observatory on Maunakea in Hawaiʻi. Using the High-Resolution Echelle Spectrometer (HIRES) instrument on the 10-meter Keck I telescope, the team confirmed that the planet, named Kepler-88 d, orbits its star every four years, and its orbit is not circular, but elliptical. At three times the mass of Jupiter, Kepler-88 d is the most massive planet in this system.

The system, Kepler-88, was already famous among astronomers for two planets that orbit much closer to the star, Kepler-88 b and c (planets are typically named alphabetically in the order of their discovery).

Transit least-squares survey -- III. A 1.9R⊕ transit candidate in the habitable zone of Kepler-160 and a nontransiting planet characterized by transit-timing variations
https://arxiv.org/abs/2006.02123

Quote :

The Sun-like star Kepler-160 (KOI-456) has been known to host two transiting planets, Kepler-160 b and c, of which planet c shows substantial transit-timing variations (TTVs). We used the archival Kepler photometry of Kepler-160 to search for additional transiting planets using a combination of our Wotan detrending algorithm and our transit least-squares (TLS) detection algorithm. We also used the Mercury N-body gravity code to study the orbital dynamics of the system. First, we recovered the known transit series of planets Kepler-160 b and c. Then we found a new transiting candidate with a radius of 1.91 (+0.17, -0.14) Earth radii (R_ear), an orbital period of 378.417 (+0.028, -0.025) d, and Earth-like insolation. The vespa software predicts that this signal has an astrophysical false-positive probability of FPP_3 = 1.8e-3 when the multiplicity of the system is taken into account. Kepler vetting diagnostics yield a multiple event statistic of MES = 10.7, which corresponds to an ~85 % reliability against false alarms due to instrumental artifacts such as rolling bands. We are also able to explain the observed TTVs of planet c with the presence of a previously unknown planet. The period and mass of this new planet, however, do not match the period and mass of the new transit candidate. Our Markov chain Monte Carlo simulations of the TTVs of Kepler-160 c can be conclusively explained by a new nontransiting planet with a mass between about 1 and 100 Earth masses and an orbital period between about 7 and 50 d. We conclude that Kepler-160 has at least three planets, one of which is the nontransiting planet Kepler-160 d. The expected stellar radial velocity amplitude caused by this new planet ranges between about 1 and 20 m/s. We also find the super-Earth-sized transiting planet candidate KOI-456.04 in the habitable zone of this system, which could be the fourth planet.

In what I am sure will be a surprise, the SETI technique of pointing a radio telescope for a few minutes in the direction of a vaguely "Earthlike" planet candidate that's been the focus of a recent press release has once again failed to find the aliens.

Perez et al. "Breakthrough Listen Search for Technosignatures Towards the Kepler-160 System"
https://arxiv.org/abs/2006.13789

Seti is a joke company they will never tell the truth even if they find something so ignore them.

Radial velocities of Kepler-456b suggest the presence of a stellar companion and a brown dwarf, but it is not clear which signal corresponds to the transit...

Dalba et al. "Multiple Explanations for the Single Transit of KIC 5951458 based on Radial Velocity Measurements Extracted with a Novel Matched-template Technique"
https://arxiv.org/abs/2008.02811

Another batch of Kepler planets. Presumably the details will show up somewhere non-paywalled at some point.

Armstrong et al. "Exoplanet Validation with Machine Learning: 50 new validated Kepler planets"
https://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/staa2498/5894933

Quote :

Armstrong et al. "Exoplanet Validation with Machine Learning: 50 new validated Kepler planets"

Full paper now on arXiv, and the tables can be accessed by downloading the original source -- click "Other Formats" under PDF, then click "[Download Source]", and change the file type of what you get to .rar or whatever and you can then extract it as a compressed folder containing the paper, the LaTeX file used to generate it, figures, tables, etc.

https://arxiv.org/abs/2008.10516

Looks like we're losing Kepler-451.

The quest for planets around subdwarfs and white dwarfs from Kepler space telescope fields: Part I. Techniques and tests of the methods
https://arxiv.org/abs/2009.02749

Sirius_Alpha wrote:

Looks like we're losing Kepler-451.

Those planets around post-common-envelope binaries don't seem to hold up so well, do they? I don't trust any of them except maybe NN Serpentis.

Update on KOI-120.01, according to the abstract (article is paywalled), it might be in a close binary system?

Judkovsky et al. (2020) "Light-curve Evolution due to Secular Dynamics and the Vanishing Transits of KOI 120.01"
https://iopscience.iop.org/article/10.3847/1538-3881/abb406

Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. I. Confirmation of an Eccentric, Cool Jupiter With an Interior Earth-sized Planet Orbiting Kepler-1514
https://arxiv.org/abs/2012.04676

Following up the Kepler field: Masses of Targets for transit timing and atmospheric characterization
https://arxiv.org/abs/2101.01202

Quote :

We identify a set of planetary systems observed by \textit{Kepler} that merit transit timing variation (TTV) analysis given the orbital periods of transiting planets, the uncertainties for their transit times and the number of transits observed during the \textit{Kepler} mission. We confirm the planetary nature of 4 KOIs within multicandidate systems. We forward model each of the planetary systems identified to determine which systems are likely to yield mass constraints that may be significantly improved upon with follow-up transit observations. We find projected TTVs diverge by more than 90 minutes after 6000 days in 27 systems, including 22 planets with orbital periods exceeding 25 days. Such targets would benefit the most from additional transit timing data. TTV follow-up could push exoplanet characterization to lower masses, at greater orbital periods and at cooler equilibrium temperatures than is currently possible from the \textit{Kepler} dataset alone. Combining TTVs and recently revised stellar parameters, we characterize an ensemble of homogeneously selected planets and identify planets in the \textit{Kepler} field with large enough estimated transmission annuli for atmospheric characterization with JWST.

https://www.caltech.edu/about/news/a-tale-of-planetary-resurrection

Years after its detection, astronomers have learned that a planet called KOI-5Ab orbits in a triple-star system with a skewed configuration.
Shortly after NASA's Kepler mission began operations back in 2009, it identified what was thought to be a planet about the size of Neptune. Called KOI-5Ab, the planet, which was the second new planet candidate to be found by the mission, was ultimately forgotten as Kepler racked up more and more planet discoveries. By the end of its mission in 2018, Kepler had discovered a whopping 2,394 exoplanets, or planets orbiting stars beyond our sun, and an additional 2,366 exoplanet candidates, including KOI-5Ab.

Now, David Ciardi, chief scientist of NASA's Exoplanet Science Institute (NExScI), located at Caltech's IPAC, says he has "resurrected KOI-5Ab from the dead," thanks to new observations from NASA's TESS (Transiting Exoplanet Survey Satellite) mission.

Led_Zep wrote:

https://www.caltech.edu/about/news/a-tale-of-planetary-resurrection

Years after its detection, astronomers have learned that a planet called KOI-5Ab orbits in a triple-star system with a skewed configuration.
Shortly after NASA's Kepler mission began operations back in 2009, it identified what was thought to be a planet about the size of Neptune. Called KOI-5Ab, the planet, which was the second new planet candidate to be found by the mission, was ultimately forgotten as Kepler racked up more and more planet discoveries. By the end of its mission in 2018, Kepler had discovered a whopping 2,394 exoplanets, or planets orbiting stars beyond our sun, and an additional 2,366 exoplanet candidates, including KOI-5Ab.

Now, David Ciardi, chief scientist of NASA's Exoplanet Science Institute (NExScI), located at Caltech's IPAC, says he has "resurrected KOI-5Ab from the dead," thanks to new observations from NASA's TESS (Transiting Exoplanet Survey Satellite) mission.

Really nice find!

(And thank you, TESS, too!)

An update from Kepler-129 system: a mass estimate for Kepler-129 c and a further non-transiting, massive planet, Kepler-129 d.

Long Period Jovian Tilts the Orbits of Two sub-Neptunes Relative to Stellar Spin Axis in Kepler-129

Quote :

We present the discovery of Kepler-129 d (P_d=7.2^+0.4_-0.3 yr, msinid=8.3^+1.1_-0.7 M_Jup, ed=0.15^+0.07_-0.05) based on six years of radial velocity (RV) observations from Keck/HIRES. Kepler-129 also hosts two transiting sub-Neptunes: Kepler-129 b (P_b=15.79 days, r_b=2.40 ± 0.04 R_⊕) and Kepler-129 c (P_c=82.20 days, r_c=2.52±0.07 R_⊕) for which we measure masses of m_b<20 M_⊕ and m_c=43⁺¹³₋₁₂ M_⊕. Kepler-129 is an hierarchical system consisting of two tightly-packed inner planets and an external companion whose mass is close to the deuterium burning limit. In such a system, two inner planets precess around the orbital normal of the outer companion, causing their inclinations to oscillate with time. Based on an asteroseismic analysis of Kepler data, we find tentative evidence that Kepler-129 b and c are misaligned with stellar spin axis by ≳38 deg, which could be torqued by Kepler-129 d if it is inclined by ≳19 deg relative to inner planets. Using N-body simulations, we provide additional constraints on the mutual inclination between Kepler-129 d and inner planets by estimating the fraction of time during which two inner planets both transit. The probability that two planets both transit decreases as their misalignment with Kepler-129 d increases. We also find a more massive Kepler-129 c enables the two inner planets to become strongly coupled and more resistant to perturbations from Kepler-129 d. The unusually high mass of Kepler-129 c provides a valuable benchmark for both planetary dynamics and interior structure, since the best-fit mass is consistent with this 2.5 R_⊕ planet having a rocky surface.

New exoplanet candidates

Constraints on Sub-Neptune Planet Candidate KOI-972.01 via Joint Variability/Gravity-darkening Analysis

Quote :

We analyze Kepler photometry of transiting planet candidate KOI-972.01, accounting for both stellar variability and gravity darkening. KOI-972.01 stands out because of its small radius, less than that of Neptune, and because of its intermediate orbit period at 13.12 days, long enough to avoid significant tidal evolution, and thus it represents an underexplored exoplanet class. The parent star of KOI-972.01 is a rapidly rotating δ-Scuti variable, complicating transit lightcurve interpretation but also offering a potential independent source of stellar parameters. We measure the stellar rotation period (16.2 hr) by identifying the stellar rotation frequency and subsequently place a constraint on the stellar obliquity of no greater than 10, but have difficulty isolating individual oscillation modes in the periodogram owing to time variation of the δ-Scuti oscillations. After subtracting the stellar oscillations, lightcurve fits place the transiting object radius at 3.07 ± 0.09 R_⊕, but the shallow transit prevents useful constraints on the system's spin-orbit alignment.

Following up the Kepler field: Masses of Targets for transit timing and atmospheric characterization

Quote :

We identify a set of planetary systems observed by Kepler that merit transit timing variation (TTV) analysis given the orbital periods of transiting planets, the uncertainties for their transit times and the number of transits observed during the Kepler mission. We confirm the planetary nature of 4 KOIs within multicandidate systems. We forward model each of the planetary systems identified to determine which systems are likely to yield mass constraints that may be significantly improved upon with follow-up transit observations. We find projected TTVs diverge by more than 90 minutes after 6000 days in 27 systems, including 22 planets with orbital periods exceeding 25 days. Such targets would benefit the most from additional transit timing data. TTV follow-up could push exoplanet characterization to lower masses, at greater orbital periods and at cooler equilibrium temperatures than is currently possible from the Kepler dataset alone. Combining TTVs and recently revised stellar parameters, we characterize an ensemble of homogeneously selected planets and identify planets in the Kepler field with large enough estimated transmission annuli for atmospheric characterization with JWST.

The two detected at KOI-3503 have just received official Kepler designation as Kepler-1703 at NASA Exoplanet Archive.

https://exoplanetarchive.ipac.caltech.edu/docs/exonews_archive.html#17June2021

Among new entries also Kepler-324 d (and e), Kepler-968 d plus the following ones not (yet) reported in Exoplanet Archive:

- Kepler-26 d
- Kepler-60 e
- Kepler-87 d
- Kepler-105 d
- Kepler-152 d & e
- Kepler-266 d
- Kepler-307 d
- Kepler-324 d & e
- Kepler-505 c
- Kepler-551 c
- Kepler-662 c, d & e
- Kepler-822 c & d
- Kepler-968 d
- KOI-2174 b, c, d & e
- KOI-3053 b & c

Welcome to Kepler-129 d as well.

Long Period Jovian Tilts the Orbits of Two sub-Neptunes Relative to Stellar Spin Axis in Kepler-129

Quote :

We present the discovery of Kepler-129 d (P_d=7.2^+0.4_-0.3 yr,  m sini_d=8.3^+1.1_-0.7 M_Jup, e_d=0.15^+0.07_-0.05) based on six years of radial velocity (RV) observations from Keck/HIRES. Kepler-129 also hosts two transiting sub-Neptunes: Kepler-129 b (P_b=15.79  days,  r_b=2.40±0.04 R_⊕) and Kepler-129 c (P_c=82.20  days,  r_c=2.52±0.07 R_⊕) for which we measure masses of  m_b<20 M_⊕ and  m_c=43⁺¹³₋₁₂ M_⊕. Kepler-129 is an hierarchical system consisting of two tightly-packed inner planets and an external companion whose mass is close to the deuterium burning limit. In such a system, two inner planets precess around the orbital normal of the outer companion, causing their inclinations to oscillate with time. Based on an asteroseismic analysis of Kepler data, we find tentative evidence that Kepler-129 b and c are misaligned with stellar spin axis by  ≳38  deg, which could be torqued by Kepler-129 d if it is inclined by  ≳19  deg relative to inner planets. Using N-body simulations, we provide additional constraints on the mutual inclination between Kepler-129 d and inner planets by estimating the fraction of time during which two inner planets both transit. The probability that two planets both transit decreases as their misalignment with Kepler-129 d increases. We also find a more massive Kepler-129 c enables the two inner planets to become strongly coupled and more resistant to perturbations from Kepler-129 d. The unusually high mass of Kepler-129 c provides a valuable benchmark for both planetary dynamics and interior structure, since the best-fit mass is consistent with this 2.5 R_⊕ planet having a rocky surface.

And finally an interesting system

Uncovering the ultimate planet impostor. An eclipsing brown dwarf in a hierarchical triple with two evolved stars

Quote :

Exoplanet searches through space-based photometric time series have shown to be very efficient in the past years. However, follow-up efforts on the detected planet candidates have demonstrated to be critical to uncover the true nature of the transiting objects. In this paper we show a detailed analysis of one of those false positives hidden as planetary signals. In this case, the candidate KOI-3886.01 showed clear evidence of a planetary nature from different techniques. Indeed, the properties of the fake planet set it among the most interesting and promising ones for the study of planetary evolution as the star leaves the main sequence. To unveil the true nature of this system, we present a complete set of observational techniques including high-spatial resolution imaging, high-precision photometric time series (showing eclipses, phase curve variations and asteroseismology signals), high-resolution spectroscopy and derived radial velocities, to unveil the true nature of this planet candidate. We find that KOI-3886.01 is an interesting false positive case: a hierarchical triple system composed by a ∼K2III giant star (KOI-3886A) accompanied by a close-in eclipsing binary formed by a sub-giant ∼G4IV star (KOI-3886B) and a brown dwarf (KOI-3886C). In particular, KOI-3886C is one of the most irradiated brown dwarfs known to date, showing the largest radius in this substellar regime. It is also the first eclipsing brown dwarf known around an evolved star. In this paper we highlight the relevance of complete sets of follow-up observations to extrasolar planets detected by the transit technique using large-pixel photometers like Kepler and TESS and in the future PLATO. Specially, the multi-color high-spatial resolution imaging was the first hint towards ruling out the planet scenario in this system.

Why planet impostor? It's always substellar object, isn't it?



But perhaps it is not going to receive an official Kepler designation for this (that is Kepler-xxxx). By the way technically the most appropriate designation for the substellar companion should be KOI-3886 Bb.

On the other hand the following Kepler planet candidates previously listed at EPE seemingly turn out as "false positives" to remove according to NASA Exoplanet Archive:

- KOI-120
- KOI-368
- KOI-771
- KIC 8012732

The list of Kepler planets lengthens.: welcome Kepler-1704, a HD 80606 b's sibling.

Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. II. Discovery of a Failed Hot Jupiter on a 2.7 Year, Highly Eccentric Orbit

Quote :

Radial velocity (RV) surveys have discovered giant exoplanets on au-scale orbits with a broad distribution of eccentricities. Those with the most eccentric orbits are valuable laboratories for testing theories of high eccentricity migration. However, few such exoplanets transit their host stars thus removing the ability to apply constraints on formation from their bulk internal compositions. We report the discovery of Kepler-1704 b, a transiting 4.15 M_J giant planet on a 988.88 day orbit with the extreme eccentricity of 0.921^+0.010_-0.015. Our decade-long RV baseline from the Keck I telescope allows us to measure the orbit and bulk heavy element composition of Kepler-1704 b and place limits on the existence of undiscovered companions. Kepler-1704 b is a failed hot Jupiter that was likely excited to high eccentricity by scattering events that possibly began during its gas accretion phase. Its final periastron distance was too large to allow for tidal circularization, so now it orbits it host from distances spanning 0.16 - 3.9 au. The maximum difference in planetary equilibrium temperature resulting from this elongated orbit is over 700 K. A simulation of the thermal phase curve of Kepler-1704 b during periastron passage demonstrates that it is a remarkable target for atmospheric characterization from the James Webb Space Telescope, which could potentially also measure the planet's rotational period as the hot spot from periastron rotates in and out of view. Continued characterization of the Kepler-1704 system promises to refine theories explaining the formation of hot Jupiters and cool giant planets like those in the solar system.

RV detection of Kepler-37 d, dis"confirmation" of the supposed Europa-sized e-planet.

A HARPS-N mass for the elusive Kepler-37d: a case study in disentangling stellar activity and planetary signals
https://arxiv.org/abs/2107.13900

Quote :

Based on RV modelling and a re-analysis of Kepler-37 TTVs, we also argue that the putative (non-transiting) planet Kepler-37e should probably be stripped of its 'confirmed' status.

Follow-up of non-transiting planets detected by Kepler. Confirmation of three hot-Jupiters and validation of three other planets
https://arxiv.org/abs/2107.14621

Quote :

The direct detection of new extrasolar planets from high-precision photometry data is commonly based on the observation of the transit signal of the planet as it passes in front of its star. Close-in planets, however, leave additional imprints in the light curve even if they do not transit. These are the so-called phase curve variations that include ellipsoidal, reflection and beaming effects. In Millholland & Laughlin (2017), the authors scrutinized the Kepler database looking for these phase variations from non-transiting planets. They found 60 candidates whose signals were compatible with planetary companions. In this paper, we perform a ground-based follow-up of a sub-sample of these systems with the aim of confirming and characterizing these planets and thus validating the detection technique. We used the CAFE and HERMES instruments to monitor the radial velocity of ten non-transiting planet candidates along their orbits. We additionally used AstraLux to obtain high-resolution images of some of these candidates to discard blended binaries that contaminate the Kepler light curves by mimicking planetary signals. Among the ten systems, we confirm three new hot-Jupiters (KIC8121913 b, KIC10068024 b, and KIC5479689 b) with masses in the range 0.5-2 MJup and set mass constraints within the planetary regime for the other three candidates (KIC8026887b, KIC5878307 b, and KIC11362225 b), thus strongly suggestive of their planetary nature. For the first time, we validate the technique of detecting non-transiting planets via their phase curve variations. We present the new planetary systems and their properties. We find good agreement between the RV-derived masses and the photometric masses in all cases except KIC8121913 b, which shows a significantly lower mass derived from the ellipsoidal modulations than from beaming and radial velocity data.

Sirius_Alpha wrote:

Follow-up of non-transiting planets detected by Kepler. Confirmation of three hot-Jupiters and validation of three other planets
https://arxiv.org/abs/2107.14621

Quote :

The direct detection of new extrasolar planets from high-precision photometry data is commonly based on the observation of the transit signal of the planet as it passes in front of its star. Close-in planets, however, leave additional imprints in the light curve even if they do not transit. These are the so-called phase curve variations that include ellipsoidal, reflection and beaming effects. In Millholland & Laughlin (2017), the authors scrutinized the Kepler database looking for these phase variations from non-transiting planets. They found 60 candidates whose signals were compatible with planetary companions. In this paper, we perform a ground-based follow-up of a sub-sample of these systems with the aim of confirming and characterizing these planets and thus validating the detection technique. We used the CAFE and HERMES instruments to monitor the radial velocity of ten non-transiting planet candidates along their orbits. We additionally used AstraLux to obtain high-resolution images of some of these candidates to discard blended binaries that contaminate the Kepler light curves by mimicking planetary signals. Among the ten systems, we confirm three new hot-Jupiters (KIC8121913 b, KIC10068024 b, and KIC5479689 b) with masses in the range 0.5-2 MJup and set mass constraints within the planetary regime for the other three candidates (KIC8026887b, KIC5878307 b, and KIC11362225 b), thus strongly suggestive of their planetary nature. For the first time, we validate the technique of detecting non-transiting planets via their phase curve variations. We present the new planetary systems and their properties. We find good agreement between the RV-derived masses and the photometric masses in all cases except KIC8121913 b, which shows a significantly lower mass derived from the ellipsoidal modulations than from beaming and radial velocity data.

KIC 8121913, KIC 10068024 and KIC 5479689 b have received official designation as Kepler-1705 b, Kepler-1706 b and Kepler-1707 b respectively.

On the other Kepler-1703 and Kepler-1704 are not listed in EPE yet among several others, among which Kepler-129 d.

Substellar third body in W UMa-type binary KIC 9026766 (though I'm not sure this is going to receive a Kepler designation, but who knows?)

First investigation of eclipsing binary KIC 9026766: analysis of light curve and periodic changes

Quote :

Abstract We investigate a short-period W UMa binary KIC 9026766 with an orbital period of 0.2721278 days in the Kepler field of view. By using an automated q-search for the folded light curve and producing a synthetic light curve for this object based on the PHOEBE code, we calculate the fundamental stellar parameters. We also analyze the O-C curve of the primary minima. The orbital period changes can be attributed to the combination of an upward quadratic function and light-travel time effect due to a possible third body with a minimum mass of 0.029 solar mass and an orbital period of 972.5866 days. The relative luminosity of the primary and secondary eclipses (Min I Min II) is calculated. The periodogram of the residuals of the LTT effect, and Min I Min II show peaks with the same period of 0.8566 days. The background effect of two nearby stars on our target is the possible reason for this signal. By considering the amplitudes and periods of the remaining signals in the OC curve of minima, spot motion is possible.

Although it is from TESS conference, this concerns Kepler planets: Kepler-807 b turns out as "Kepler-807 B", a very low-mass M dwarf star.

Kepler-807 B: A Highly Eccentric Companion Near the Stellar Transition

Quote :

The traditional boundary between brown dwarfs and M-dwarfs is a mass limit for sustainable hydrogen fusion (~80 M_J). Discovering and characterizing objects near this transition point offers a unique opportunity to test our substellar and stellar evolution models, while studying the nature of this transition. Using observations from Kepler combined with ground-based radial velocity measurements from Keck-HIRES and APOGEE, we confirmed and measured the mass of Kepler-807 B. This companion is on a highly eccentric (0.69) 117 day orbit, and from our analysis we measured a radius of 1.002 ± 0.048 R_J and a mass of 82.4 ± 3.6 M_J, too massive to be an exoplanet as previously characterized. This system is part of the Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey to discover and characterize long period giant planets in Kepler, K2, and TESS.

Nevertheless I wonder if Kepler planet candidates classed as VLM stars are being or going to be followed up in search for longer-period circumbinary planets too, transiting or not. And not only Kepler ones...

Additionally new recovered Kepler planets

Rescuing Unrecognized Exoplanet Candidates in Kepler Data

Quote :

The prime Kepler mission detected 34,032 transit-like signals, out of which 8,054 were identified as likely due to astrophysical planet transits or eclipsing binaries. We manually examined 306 of the remaining 25,978 detections, and found six plausible transiting or eclipsing objects, five of which are plausible planet candidates (PCs), and one stellar companion. One of our new PCs is a possible new second planet in the KOI 4302 system. Another new PC is a possible new planet around the KOI 4246, and when combined with a different possible planet rescued by the False Positive Working Group, we find that KOI 4246 may be a previously unrecognized three-planet system.