- ID:
- ivo://CDS.VizieR/J/ApJ/770/69
- Title:
- Kepler planet candidates radii
- Short Name:
- J/ApJ/770/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carry out an independent search of Kepler photometry for small transiting planets with sizes 0.5-8.0 times that of Earth and orbital periods between 5 and 50 days, with the goal of measuring the fraction of stars harboring such planets. We use a new transit search algorithm, TERRA, optimized to detect small planets around photometrically quiet stars. We restrict our stellar sample to include the 12000 stars having the lowest photometric noise in the Kepler survey, thereby maximizing the detectability of Earth-size planets. We report 129 planet candidates having radii less than 6R_E_ found in three years of Kepler photometry (quarters 1-12). Forty-seven of these candidates are not in Batalha et al. (J/ApJS/204/24), which only analyzed photometry from quarters 1-6. We gather Keck HIRES spectra for the majority of these targets leading to precise stellar radii and hence precise planet radii. We make a detailed measurement of the completeness of our planet search. We inject synthetic dimmings from mock transiting planets into the actual Kepler photometry. We then analyze that injected photometry with our TERRA pipeline to assess our detection completeness for planets of different sizes and orbital periods. We compute the occurrence of planets as a function of planet radius and period, correcting for the detection completeness as well as the geometric probability of transit, R_*_/a. The resulting distribution of planet sizes exhibits a power law rise in occurrence from 5.7R_E_ down to 2R_E_, as found in Howard et al. (2012ApJS..201...15H). That rise clearly ends at 2R_E_. The occurrence of planets is consistent with constant from 2R_E_ toward 1R_E_. This unexpected plateau in planet occurrence at 2R_E_ suggests distinct planet formation processes for planets above and below 2R_E_.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/566/A103
- Title:
- Kepler planet host candidates imaging
- Short Name:
- J/A+A/566/A103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kepler mission has discovered thousands of planet candidates. Currently, some of them have already been discarded; more than 200 have been confirmed by follow-up observations (most by radial velocity and few by other methods), and several hundreds have been validated. However, the large majority of the candidates are still awaiting for confirmation. Thus, priorities (in terms of the probability of the candidate being a real planet) must be established for subsequent radial velocity observations. The motivation of this work is to provide a set of isolated (good) host candidates to be further tested by other techniques that allow confirmation of the planet. As a complementary goal, we aim to identify close companions of the candidates that could have contaminated the light curve of the planet host due to the large pixel size of the Kepler CCD and its typical PSF of around 6 arcsec. Both goals can also provide robust statistics about the multiplicity of the Kepler hosts. We used the AstraLux North instrument located at the 2.2m telescope in the Calar Alto Observatory (Almeria, Spain) to obtain diffraction-limited images of 174 Kepler objects of interest. A sample of demoted Kepler objects of interest (with rejected planet candidates) is used as a control for comparison of multiplicity statistics. The lucky-imaging technique used in this work is compared to other adaptive optics and speckle imaging observations of Kepler planet host candidates. To that end, we define a new parameter, the blended source confidence level (BSC), to assess the probability of an object to have blended non-detected eclipsing binaries capable of producing the detected transit.
- ID:
- ivo://CDS.VizieR/J/ApJ/787/80
- Title:
- 139 Kepler planets transit time variations
- Short Name:
- J/ApJ/787/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extract densities and eccentricities of 139 sub-Jovian planets by analyzing transit time variations (TTVs) obtained by the Kepler mission through Quarter 12. We partially circumvent the degeneracies that plague TTV inversion with the help of an analytical formula for the TTV. From the observed TTV phases, we find that most of these planets have eccentricities of the order of a few percent. More precisely, the rms eccentricity is 0.018_-0.004_^+0.005^, and planets smaller than 2.5 R_{earth}_ are around twice as eccentric as those bigger than 2.5 R_{earth}_. We also find a best-fit density-radius relationship {rho}~3 g/cm^3^x(R/3 R_{earth}_)^-2.3^ for the 56 planets that likely have small eccentricity and hence small statistical correction to their masses. Many planets larger than 2.5 R_{earth}_are less dense than water, implying that their radii are largely set by a massive hydrogen atmosphere.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A90
- Title:
- Kepler-419 radial velocities
- Short Name:
- J/A+A/615/A90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kepler-419 is a planetary system discovered by the Kepler photometry which is known to harbour two massive giant planets: an inner 3M_J_ transiting planet with a 69.8-day period, highly eccentric orbit, and an outer 7.5M_J_ non-transiting planet predicted from the transit-timing variations (TTVs) of the inner planet b to have a 675-day period, moderately eccentric orbit. Here we present new radial velocity (RV) measurements secured over more than two years with the SOPHIE spectrograph, where both planets are clearly detected. The RV data is modelled together with the Kepler photometry using a photodynamical model. The inclusion of velocity information breaks the MR^-3^ degeneracy inherent in timing data alone, allowing us to measure the absolute stellar and planetary radii and masses. With uncertainties of 12 and 13% for the stellar and inner planet radii, and 35, 24, and 35% for the masses of the star, planet b, and planet c, respectively, these measurements are the most precise to date for a single host star system using this technique. The transiting planet mass is determined at better precision than the star mass. This shows that modelling the radial velocities and the light curve together in systems of dynamically interacting planets provides a way of characterising both the star and the planets without being limited by knowledge of the star. On the other hand, the period ratio and eccentricities place the Kepler-419 system in a sweet spot; had around twice as many transits been observed, the mass of the transiting planet could have been measured using its own TTVs. Finally, the origin of the Kepler-419 system is discussed. We show that the system is near a coplanar high-eccentricity secular fixed point, related to the alignment of the orbits, which has prevented the inner orbit from circularising. For most other relative apsidal orientations, planet b's orbit would be circular with a semi-major axis of 0.03au. This suggests a mechanism for forming hot Jupiters in multiplanetary systems without the need of high mutual inclinations.
- ID:
- ivo://CDS.VizieR/J/ApJ/871/174
- Title:
- Kepler rapid rotators and Ks-band excesses
- Short Name:
- J/ApJ/871/174
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tens of thousands of rotation periods have been measured in the Kepler fields, including a substantial fraction of rapid rotators. We use Gaia parallaxes to distinguish photometric binaries (PBs) from single stars on the unevolved lower main sequence, and compare their distribution of rotation properties to those of single stars both with and without Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectroscopic characterization. We find that 59% of stars with 1.5day<P<7day lie 0.3mag above the main sequence, compared with 28% of the full rotation sample. The fraction of stars in the same period range is 1.7{+/-}0.1% of the total sample analyzed for rotation periods. Both the PB fraction and the fraction of rapid rotators are consistent with a population of non-eclipsing short-period binaries inferred from Kepler eclipsing binary data after correcting for inclination. This suggests that the rapid rotators are dominated by tidally synchronized binaries rather than single stars obeying traditional angular momentum evolution. We caution against interpreting rapid rotation in the Kepler field as a signature of youth. Following up on this new sample of 217 candidate tidally synchronized binaries will help further understand tidal processes in stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/789/154
- Title:
- Kepler-10 RV measurements by HARPS-N
- Short Name:
- J/ApJ/789/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kepler-10b was the first rocky planet detected by the Kepler satellite and confirmed with radial velocity follow-up observations from Keck-HIRES. The mass of the planet was measured with a precision of around 30%, which was insufficient to constrain models of its internal structure and composition in detail. In addition to Kepler-10b, a second planet transiting the same star with a period of 45 days was statistically validated, but the radial velocities were only good enough to set an upper limit of 20 M_{Earth}_ for the mass of Kepler-10c. To improve the precision on the mass for planet b, the HARPS-N Collaboration decided to observe Kepler-10 intensively with the HARPS-N spectrograph on the Telescopio Nazionale Galileo on La Palma. In total, 148 high-quality radial-velocity measurements were obtained over two observing seasons. These new data allow us to improve the precision of the mass determination for Kepler-10b to 15%. With a mass of 3.33+/-0.49 M_{Earth}_and an updated radius of 1.47_-0.02_^+0.03^ R_{Earth}_, Kepler-10b has a density of 5.8+/-0.8 g/cm3, very close to the value predicted by models with the same internal structure and composition as the Earth. We were also able to determine a mass for the 45-day period planet Kepler-10c, with an even better precision of 11%. With a mass of 17.2+/-1.9 M_{Earth}_ and radius of 2.35_-0.04_^+0.09^ R_{Earth}_, Kepler-10c has a density of 7.1+/-1.0 g/cm3. Kepler-10c appears to be the first strong evidence of a class of more massive solid planets with longer orbital periods.
- ID:
- ivo://CDS.VizieR/J/ApJS/197/8
- Title:
- Kepler's candidate multiple transiting planets
- Short Name:
- J/ApJS/197/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- About one-third of the ~1200 transiting planet candidates detected in the first four months of Kepler data are members of multiple candidate systems. There are 115 target stars with two candidate transiting planets, 45 with three, 8 with four, and 1 each with five and six. We characterize the dynamical properties of these candidate multi-planet systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean-motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to be in resonance, particularly near the 2:1 resonance. We find that virtually all candidate systems are stable, as tested by numerical integrations that assume a nominal mass-radius relationship. Several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. We provide constraints on the true multiplicity and mutual inclination distribution of the multi-candidate systems, revealing a population of systems with multiple super-Earth-size and Neptune-size planets with low to moderate mutual inclinations.
- ID:
- ivo://CDS.VizieR/J/ApJ/784/45
- Title:
- Kepler's multiple planet candidates. III.
- Short Name:
- J/ApJ/784/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kepler mission has discovered more than 2500 exoplanet candidates in the first two years of spacecraft data, with approximately 40% of those in candidate multi-planet systems. The high rate of multiplicity combined with the low rate of identified false positives indicates that the multiplanet systems contain very few false positive signals due to other systems not gravitationally bound to the target star. False positives in the multi-planet systems are identified and removed, leaving behind a residual population of candidate multi-planet transiting systems expected to have a false positive rate less than 1%. We present a sample of 340 planetary systems that contain 851 planets that are validated to substantially better than the 99% confidence level; the vast majority of these have not been previously verified as planets. We expect ~two unidentified false positives making our sample of planet very reliable. We present fundamental planetary properties of our sample based on a comprehensive analysis of Kepler light curves, ground-based spectroscopy, and high-resolution imaging. Since we do not require spectroscopy or high-resolution imaging for validation, some of our derived parameters for a planetary system may be systematically incorrect due to dilution from light due to additional stars in the photometric aperture. Nonetheless, our result nearly doubles the number verified exoplanets.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/91
- Title:
- Kepler stars with infrared excess
- Short Name:
- J/MNRAS/426/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a search for infrared excess emission from dusty circumstellar material around 180000 stars observed by the Kepler and Wide-field Infrared Survey Explorer missions. This study is motivated by (i) the potential to find bright warm discs around planet host stars, (ii) a need to characterize the distribution of rare warm discs and (iii) the possible identification of candidates for discovering transiting dust concentrations. We find about 8000 stars that have excess emission, mostly at 12um.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/2342
- Title:
- 4 Kepler systems transit timing observations
- Short Name:
- J/MNRAS/421/2342
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a method to confirm the planetary nature of objects in systems with multiple transiting exoplanet candidates. This method involves a Fourier-domain analysis of the deviations in the transit times from a constant period that result from dynamical interactions within the system. The combination of observed anticorrelations in the transit times and mass constraints from dynamical stability allow us to claim the discovery of four planetary systems, Kepler-25, Kepler-26, Kepler-27 and Kepler-28, containing eight planets and one additional planet candidate.
