Kepler News and Results (Thread 2)

Nope. We never saw that system published.

Sirius_Alpha wrote:

Nope. We never saw that system published.

Strange.

Same thing for Kepler-72, I realized this today too. False positives? Identical systems with different numbers? Who knows.

Another "mystery" here in this previous post of mine:

Edasich wrote:

A small riddle.

EPE announces two small planets at Kepler-1705, seemingly a metal-poor Solar sibling in Cygnus

http://exoplanet.eu/catalog/kepler-1705_b/
http://exoplanet.eu/catalog/kepler-1705_c/

Aka KOI-4772, which hosts a third planet candidate in outer orbit too.

However ExofopTESS assigns Kepler-1705 to another star, KIC 8121913, which hosts a massive Hot Jupiter but no small planets. On the other hand there KOI-4772 seems not having an official Kepler designation yet. How possible?

Edasich wrote:

A small riddle.

EPE announces two small planets at Kepler-1705, seemingly a metal-poor Solar sibling in Cygnus

http://exoplanet.eu/catalog/kepler-1705_b/
http://exoplanet.eu/catalog/kepler-1705_c/

Aka KOI-4772, which hosts a third planet candidate in outer orbit too.

However ExofopTESS assigns Kepler-1705 to another star, KIC 8121913, which hosts a massive Hot Jupiter but no small planets. On the other hand there KOI-4772 seems not having an official Kepler designation yet. How possible?

Riddle solved!
The hot Jupiter host is now labeled as Kepler-1970 and the small planets host keeps the Kepler-1705 designation. Now they have just to be listed at EPE and everything’s okay.

Update for Kepler-33 system

Refining the Masses and Radii of the Star Kepler-33 and its Five Transiting Planets
https://arxiv.org/abs/2211.00703

Very long transit from long period planet Kepler-167 e

A 16 Hour Transit Observed by the Unistellar Network

Quote :

More than 5,000 exoplanets have been confirmed and among them almost 4,000 were discovered by the transit method. However, few transiting exoplanets have an orbital period greater than 100 days. Here we report a transit detection of Kepler-167 e, a "Jupiter analog" exoplanet orbiting a K4 star with a period of 1,071 days, using the Unistellar ground-based telescope network. From 2021 November 18 to 20, citizen astronomers located in nine different countries gathered 43 observations, covering the 16 hour long transit. Using a nested sampling approach to combine and fit the observations, we detected the mid-transit time to be UTC 2021 November 19 17:20:51 with a 1σ uncertainty of 9.8 minutes, making it the longest-period planet to ever have its transit detected from the ground. This is the fourth transit detection of Kepler-167 e, but the first made from the ground. This timing measurement refines the orbit and keeps the ephemeris up to date without requiring space telescopes. Observations like this demonstrate the capabilities of coordinated networks of small telescopes to identify and characterize planets with long orbital periods.

Second planet in KOI-984 system confirmed
http://exoplanet.eu/catalog/koi-984_c/

A highly mutually-inclined, compact warm-Jupiter system KOI-984 ?

Quote :

The discovery of a population of close-orbiting giant planets (≤ 1 au) has raised a number of questions about their origins and dynamical histories. These issues have still not yet been fully resolved, despite over 20 years of exoplanet detections and a large number of discovered exoplanets. In particular, it is unclear whether warm Jupiters (WJs) form in situ, or whether they migrate from further outside and are even currently migrating to form hot Jupiters (HJs). Here, we report the possible discovery and characterization of the planets in a highly mutually-inclined (Imut≃45∘), compact two-planet system (KOI-984), in which the newly discovered warm Jupiter KOI-984c is on a 21.5-day, moderately eccentric (e≃0.4) orbit, in addition to a previously known 4.3-day planet candidate KOI-984b. Meanwhile, the orbital configuration of a moderately inclined (Imut≃15∘), low-mass (mc≃24M⊕;Pb≃8.6 days) perturbing planet near 1:2 mean motion resonace with KOI-984b could also well reproduce observed transit timing variations and transit duration variations of KOI-984b. Such an eccentric WJ with a close-in sibling would pose a challenge to the proposed formation and migration mechanisms of WJs, if the first scenario is supported with more evidences in near future; this system with several other well-measured inclined WJ systems (e.g., Kepler-419 and Kepler-108) may provide additional clues for the origin and dynamical histories of WJs.

When and which will official Kepler designation be assigned to this system?

Evidence from spot transits that the planets of Kepler-210 may have significant mutual inclination, with Kepler-210b aligned with the stellar equator, while Kepler-210c is likely tilted by ~34.8°.

Valio & Araújo (2022) "Stellar Obliquity from Spot Transit Mapping of Kepler-210"
https://iopscience.iop.org/article/10.3847/1538-4357/ac9af6

Quote :

When and which will official Kepler designation be assigned to this system?

Kepler-1973, enough said.

Likely “watery” composition for Kepler-138 d and hints of a fourth planet in the system
https://www.jpl.nasa.gov/news/two-exoplanets-may-be-mostly-water-nasas-hubble-and-spitzer-find

Pretty interesting as at the beginning they seemed to be totally different .Is any pdf paper available How precise is stellar radius as to it was some doubts when I last time was on the forum

tommi59 wrote:

Pretty interesting as at the beginning they seemed to be totally different .Is any pdf paper available How precise is stellar radius as to it was some doubts when I last time was on the forum

Here it is: https://arxiv.org/abs/2212.08477

Kepler-80 Revisited: Assessing the Participation of a Newly Discovered Planet in the Resonant Chain

Quote :

In this paper, we consider the chain of resonances in the Kepler-80 system and evaluate the impact that the additional member of the resonant chain discovered by Shallue & Vanderburg (2018) has on the dynamics of the system and the physical parameters that can be recovered by a fit to the transit timing variations (TTVs). Ultimately, we calculate the mass of Kepler-80 g to be 0.8±0.3M⊕ when assuming all planets have zero eccentricity, and 1.0±0.3 M⊕ when relaxing that assumption. We show that the outer five planets are in successive three-body mean-motion resonances (MMRs). We assess the current state of two-body MMRs in the system and find that the planets do not appear to be in two-body MMRs. We find that while the existence of the additional member of the resonant chain does not significantly alter the character of the Kepler-80 three-body MMRs, it can alter the physical parameters derived from the TTVs, suggesting caution should be applied when drawing conclusions from TTVs for potentially incomplete systems. We also compare our results to those of MacDonald et al. (2021), who perform a similar analysis on the same system with a different method. Although the results of this work and MacDonald et al. (2021) show that different fit methodologies and underlying assumptions can result in different measured orbital parameters, the most secure conclusion is that which holds true across all lines of analysis: Kepler-80 contains a chain of planets in three-body MMRs but not in two-body MMRs.

Close eclipsing binaries can have not only circumbinary planets, even circumstellar ones: the case of KOI-126 or Kepler-469.

Improving circumbinary planet detections by fitting their binary's apsidal precession

http://exoplanet.eu/catalog/koi-126_b/

Characterization of low-mass companions to Kepler objects of interest observed with APOGEE-N

Quote :

We report the characterization of 28 low-mass (0.02 M⊙≤ M2≤0.25 M⊙) companions to Kepler objects of interest (KOIs), eight of which were previously designated confirmed planets. These objects were detected as transiting companions to Sun-like stars (G and F dwarfs) by the Kepler mission and are confirmed as single-lined spectroscopic binaries in the current work using the northern multiplexed Apache Point Observatory Galactic Evolution Experiment near-infrared spectrograph (APOGEE-N) as part of the third and fourth Sloan Digital Sky Surveys. We have observed hundreds of KOIs using APOGEE-N and collected a total of 43,175 spectra with a median of 19 visits and a median baseline of ∼1.9 years per target. We jointly model the Kepler photometry and APOGEE-N radial velocities to derive fundamental parameters for this subset of 28 transiting companions. The radii for most of these low-mass companions are over-inflated (by ∼10%) when compared to theoretical models. Tidally locked M dwarfs on short period orbits show the largest amount of inflation, but inflation is also evident for companions that are well separated from the host star. We demonstrate that APOGEE-N data provides reliable radial velocities when compared to precise high-resolution spectrographs that enable detailed characterization of individual systems and the inference of orbital elements for faint (H>12) KOIs. The data from the entire APOGEE-KOI program is public and presents an opportunity to characterize an extensive subset of the binary population observed by Kepler.

Updates for some old and new Kepler systems:
- KOI-2513 is found to host a 22 Mj planet or brown dwarf in 19 d orbit.
- Kepler-494 b is a 37 Mj brown dwarf.
- KOI-415 b is a 65 Mj brown dwarf.
- Kepler-807 b is actually a very low-mass star (88 Mj), the same applies for KOI-242.01 (i.e. Kepler-503 b, 77 Mj).

The Kepler Giant Planet Search. I: A Decade of Kepler Planet Host Radial Velocities from W. M. Keck Observatory
https://arxiv.org/abs/2304.00071

Quote :

Despite the importance of Jupiter and Saturn to Earth's formation and habitability, there has not yet been a comprehensive observational study of how giant exoplanets correlate with the architectural properties of close-in, sub-Neptune sized exoplanets. This is largely because transit surveys are particularly insensitive to planets at orbital separations > 1 AU, and so their census of Jupiter-like planets is incomplete, inhibiting our study of the relationship between Jupiter-like planets and the small planets that do transit. To establish the relationship between small and giant planets, we conducted the Kepler Giant Planet Survey (KGPS). Using W. M. Keck Observatory HIRES, we spent over a decade collecting 2858 RVs (2181 of which are presented here for the first time) of 63 sun-like stars that host 157 transiting planets. We had no prior knowledge of which systems would contain giant planets beyond 1 AU, making this survey unbiased in detected Jovians. In this paper, we announce RV-detected companions to 20 stars from our sample. These include 13 Jovians (0.3 MJ < M sin i < 13 MJ, 1 < a < 10 AU), 7 non-transiting sub-Saturns, and 3 stellar-mass companions. We also present updated masses and densities of 84 transiting planets. The KGPS project leverages the longest-running and most data-rich collection of RVs of the NASA Kepler systems yet, and will provide a basis for addressing whether giant planets help or hinder the growth of sub-Neptune sized and terrestrial planets. Future KGPS papers will examine the relationship between small, transiting planets and their companions.

Cold Jupiters and improved masses in 38 Kepler and K2 small-planet systems from 3661 high-precision HARPS-N radial velocities. No excess of cold Jupiters in small-planet systems
https://arxiv.org/abs/2304.05773

Quote :

The exoplanet population with orbital periods P<100 d around solar-type stars is dominated by super-Earths and sub-Neptunes. These planets are, however, missing in our Solar System, and the reason for that is unknown. Two theoretical scenarios invoke the role of Jupiter as the possible culprit: Jupiter may have acted as a dynamical barrier to the inward migration of sub-Neptunes from beyond the water iceline or, alternatively, may have reduced considerably the inward flux of material (pebbles) required to form super-Earths inside that iceline. Both scenarios predict an anti-correlation between the presence of small planets (SPs) and that of cold Jupiters (CJs) in exoplanetary systems. To test that prediction, we homogeneously analyzed the radial-velocity (RV) measurements of 38 Kepler and K2 transiting SP systems gathered over almost 10 years with the HARPS-N spectrograph, as well as publicly available RVs collected with other facilities. We detected five CJs in three systems, two in Kepler-68, two in Kepler-454, and a very eccentric one in K2-312. We derived an occurrence rate of 9.3+7.7−2.9% for CJs with 0.3−13 MJup and 1-10 au, which is lower but still compatible at 1.3σ with that measured from RV surveys for solar-type stars, regardless of SP presence. This does not allow us to draw a firm conclusion about the predicted anti-correlation between SPs and CJs, which would require a considerably larger sample. Nevertheless, we found no evidence of previous claims of an excess of CJs in SP systems. As an important by-product of our analyses, we homogeneously determined the masses of 64 Kepler and K2 small planets, reaching a precision better than 5, 7.5 and 10σ for 25, 13 and 8 planets, respectively. Finally, we release to the scientific community the 3661 HARPS-N radial velocities used in this work.

Note: K2-312 is listed as HD 80653.

New Kepler planets up to Kepler-2000 and 2001

Multiplicity Boost Of Transit Signal Classifiers: Validation of 69 New Exoplanets Using The Multiplicity Boost of ExoMiner
https://arxiv.org/abs/2305.02470

A 5 M_Jup Non-Transiting Coplanar Circumbinary Planet Around Kepler-1660AB

Quote :

Over a dozen transiting circumbinary planets have been discovered around eclipsing binaries. Transit detections are biased towards aligned planet and binary orbits, and indeed all of the known planets have mutual inclinations less than 4.5∘. One path to discovering circumbinary planets with misaligned orbits is through eclipse timing variations (ETVs) of non-transiting planets. Borkovits et al. (2016) discovered ETVs on the 18.6 d binary Kepler-1660AB, indicative of a third body on a ≈236 d period, with a misaligned orbit and a potentially planetary mass. Getley et al. (2017) agreed with the planetary hypothesis, arguing for a 7.7MJup circumbinary planet on an orbit that is highly misaligned by 120∘ with respect to the binary. In this paper, we obtain the first radial velocities of the binary. We combine these with an analysis of not only the ETVs but also the eclipse depth variations. We confirm the existence of a 239.5 d circumbinary planet, but with a lower mass of 4.87MJup and a coplanar orbit. The misaligned orbits proposed by previous authors are definitively ruled out by a lack of eclipse depth variations. Kepler-1660ABb is the first confirmed circumbinary planet found using ETVs around a main sequence binary.

Additional non-transiting planet in Kepler-1513 system
Not So Fast Kepler-1513: A Perturbing Planetary Interloper in the Exomoon Corridor
https://arxiv.org/list/astro-ph.EP/new

Updated Catalog of Kepler Planet Candidates: Focus on Accuracy and Orbital Periods
https://arxiv.org/abs/2311.00238

Here update for Kepler-385 system is presented.