- ID:
- ivo://CDS.VizieR/J/AJ/155/206
- Title:
- Search for rings around Kepler planet candidates
- Short Name:
- J/AJ/155/206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a systematic search for rings around 168 Kepler planet candidates with sufficient signal-to-noise ratios that are selected from all of the short-cadence data. We fit ringed and ringless models to their light curves and compare the fitting results to search for the signatures of planetary rings. First, we identify 29 tentative systems, for which the ringed models exhibit statistically significant improvement over the ringless models. The light curves of those systems are individually examined, but we are not able to identify any candidate that indicates evidence for rings. In turn, we find several mechanisms of false positives that would produce ringlike signals, and the null detection enables us to place upper limits on the size of the rings. Furthermore, assuming the tidal alignment between axes of the planetary rings and orbits, we conclude that the occurrence rate of rings larger than twice the planetary radius is less than 15%. Even though the majority of our targets are short-period planets, our null detection provides statistical and quantitative constraints on largely uncertain theoretical models of the origin, formation, and evolution of planetary rings.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/159/124
- Title:
- Searching Kepler data. I. 17 new planets
- Short Name:
- J/AJ/159/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an independent search of all ~200000 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-7340288b, that is both rocky (radius=<1.6R_{Earth}_) 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".
- ID:
- ivo://CDS.VizieR/J/MNRAS/491/5489
- Title:
- Semi-detached double-lined eclipsing binaries
- Short Name:
- J/MNRAS/491/5489
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Semidetached eclipsing systems provide a unique opportunity to derive the basic properties of interacting binaries. The goal of this work is to collect and to make use of data on semidetached systems with available light and radial velocity curve solutions. I have compiled the most comprehensive list to date, of 119 semidetached double-lined eclipsing binaries, containing the orbital parameters and physical parameters of the components. I consider the classification of semidetached binaries and discuss gaps between various classes in the Hertzspung-Russell diagram. I list systems with component parameters that are inverted and briefly discuss their evolutionary state.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/88
- Title:
- Short-duration stellar flares from GALEX & Kepler
- Short Name:
- J/ApJ/883/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a population of short-duration near-ultraviolet (NUV) flares in stars observed by the Kepler and Galaxy Evolution Explorer (GALEX) missions. We analyzed the NUV light curves of 34276 stars observed from 2009 to 2013 by both the GALEX (NUV) and Kepler (optical) space missions with the eventual goal of investigating multiwavelength flares. From the GALEX data, we constructed light curves with a 10s cadence, and we ultimately detected 1904 short-duration flares on 1021 stars. The vast majority (94.5%) of these flares have durations less than 5 minutes, with flare flux enhancements above the quiescent flux level ranging from 1.5 to 1700. The flaring stars are primarily solar-like, with Teff ranging from 3000 to 11000K and radii between 0.5 and 15R_{sun}_. This set of flaring stars is almost entirely distinct from that of previous flare surveys of Kepler data and indicates a previously undetected collection of small flares contained within the Kepler sample. The range in flare energies spans 1.8x10^32^-8.9x10^37^erg, with associated relative errors spanning 2%-87%. The flare frequency distribution by energy follows a power law with index {alpha}=1.72+/-0.05, consistent with results of other solar and stellar flare studies at a range of wavelengths. This supports the idea that the NUV flares we observed are governed by the same physical processes present in solar and optical flares. The relationship between flare duration and associated flare energy extends results found for solar and stellar white-light flares, and suggests that these flares originate in regions with magnetic field strengths of several hundred Gauss, and length scales of the order of 10^10^cm.
- ID:
- ivo://CDS.VizieR/J/ApJS/239/2
- Title:
- Simulated exoplanets from TESS list of targets
- Short Name:
- J/ApJS/239/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transiting Exoplanet Survey Satellite (TESS) has a goal of detecting small planets orbiting stars bright enough for mass determination via ground-based radial velocity observations. Here, we present estimates of how many exoplanets the TESS mission will detect, the physical properties of the detected planets, and the properties of the stars that those planets orbit. This work uses stars drawn from the TESS Input Catalog (TIC) Candidate Target List and revises yields from prior studies that were based on Galactic models. We modeled the TESS observing strategy to select approximately 200000 stars at 2-minute cadence, while the remaining stars are observed at 30-minute cadence in full-frame image data. We placed zero or more planets in orbit around each star, with physical properties following measured exoplanet occurrence rates, and used the TESS noise model to predict the derived properties of the detected exoplanets. In the TESS 2-minute cadence mode we estimate that TESS will find 1250+/-70 exoplanets (90% confidence), including 250 smaller than 2R_{Earth}_. Furthermore, we predict that an additional 3100 planets will be found in full-frame image data orbiting bright dwarf stars and more than 10000 around fainter stars. We predict that TESS will find 500 planets orbiting M dwarfs, but the majority of planets will orbit stars larger than the Sun. Our simulated sample of planets contains hundreds of small planets amenable to radial velocity follow-up, potentially more than tripling the number of planets smaller than 4R_{Earth}_ with mass measurements. This sample of simulated planets is available for use in planning follow-up observations and analyses.
- ID:
- ivo://CDS.VizieR/J/AJ/156/277
- Title:
- Sixty validated planets from K2 campaigns 5-8
- Short Name:
- J/AJ/156/277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a uniform analysis of 155 candidates from the second year of NASA's K2 mission (Campaigns 5-8), yielding 60 statistically validated planets spanning a range of properties with median values of R_p_=2.5 R_{Earth}_, P=7.1 days, T_eq_=811 K, and J=11.3 mag. The sample includes 24 planets in 11 multiplanetary systems, as well as 18 false positives and 77 remaining planet candidates. Of particular interest are 18 planets smaller than 2 R_{Earth}_, five orbiting stars brighter than J=10 mag, and a system of four small planets orbiting the solar-type star EPIC 212157262. We compute planetary transit parameters and false-positive probabilities using a robust statistical framework and present a complete analysis incorporating the results of an intensive campaign of high-resolution imaging and spectroscopic observations. This work brings the K2 yield to over 360 planets, and by extrapolation, we expect that K2 will have discovered ~600 planets before the expected depletion of its onboard fuel in late 2018.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A63
- Title:
- Slow-rotator sequence radii
- Short Name:
- J/A+A/597/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Average stellar radii in open clusters can be estimated from rotation periods and projected rotational velocities under the assumption of random orientation of the spin axis. Such estimates are independent of distance, interstellar absorption, and models, but their validity can be limited by missing data (truncation) or data that only represent upper/lower limits (censoring). We present a new statistical analysis method to estimate average stellar radii in the presence of censoring and truncation. We use theoretical distribution functions of the projected stellar radius Rsini to define a likelihood function in the presence of censoring and truncation. Average stellar radii in magnitude bins are then obtained by a maximum likelihood parametric estimation procedure. This method is capable of recovering the average stellar radius within a few percent with as few as ~10 measurements. Here it is applied for the first time to the dataset available for the Pleiades. We find an agreement better than ~10 percent between the observed R vs M_K_ relationship and current standard stellar models for 1.2>=M/M_{sun}_>=0.85 with no evident bias. Evidence of a systematic deviation at 2sigma level are found for stars with 0.8>=M/M_{sun}_=0.6 approaching the slow-rotator sequence. Fast-rotators (P<2d) agree with standard models within 15 percent with no systematic deviations in the whole 1.2>=M/M_{sun}_>=0.5 range. The evidence found of a possible radius inflation just below the lower mass limit of the slow-rotator sequence indicates a possible connection with the transition from the fast to the slow-rotator sequence.
- ID:
- ivo://CDS.VizieR/J/ApJS/210/20
- Title:
- Small Kepler planets radial velocities
- Short Name:
- J/ApJS/210/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g/cm3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than ~2 R_{oplus}_. Larger planets evidently contain a larger fraction of low-density material (H, He, and H_2_O).
199. SOAR TESS survey. I.
- ID:
- ivo://CDS.VizieR/J/AJ/159/19
- Title:
- SOAR TESS survey. I.
- Short Name:
- J/AJ/159/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transiting Exoplanet Survey Satellite (TESS) is finding transiting planet candidates around bright, nearby stars across the entire sky. The large field of view, however, results in low spatial resolution; therefore, multiple stars contribute to almost every TESS light curve. High angular resolution imaging can detect the previously unknown companions to planetary candidate hosts that dilute the transit depths, lead to host star ambiguity, and, in some cases, are the source of false-positive transit signals. We use speckle imaging on the Southern Astrophysical Research (SOAR) telescope to search for companions to 542 TESS planet candidate hosts in the southern sky. We provide correction factors for the 117 systems with resolved companions due to photometric contamination. The contamination in TESS due to close binaries is similar to that found in surveys of Kepler planet candidates. For the solar-type population, we find a deep deficit of close binary systems with projected stellar separations less than 100 au among planet candidate hosts (44 observed binaries compared to 124 expected based on field binary statistics). The close binary suppression among TESS planet candidate hosts is similar to that seen for the more distant Kepler population. We also find a large surplus of TESS planet candidates in wide binary systems detected in both SOAR and Gaia DR2 (Cat. I/345) (119 observed binaries compared to 77 expected). These wide binaries almost exclusively host giant planets, however, suggesting that orbital migration caused by perturbations from the stellar companion may lead to planet-planet scattering and suppress the population of small planets in wide binaries. Both trends are also apparent in the M dwarf planet candidate hosts.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/188
- Title:
- Spectra of nearby late K and M Kepler stars
- Short Name:
- J/ApJ/779/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use moderate-resolution spectra of nearby late K and M dwarf stars with parallaxes and interferometrically determined radii to refine their effective temperatures, luminosities, and metallicities. We use these revised values to calibrate spectroscopic techniques to infer the fundamental parameters of more distant late-type dwarf stars. We demonstrate that, after masking out poorly modeled regions, the newest version of the PHOENIX atmosphere models accurately reproduce temperatures derived bolometrically. We apply methods to late-type hosts of transiting planet candidates in the Kepler field, and calculate effective temperature, radius, mass, and luminosity with typical errors of 57K, 7%, 11%, and 13%, respectively. We find systematic offsets between our values and those from previous analyses of the same stars, which we attribute to differences in atmospheric models utilized for each study. We investigate which of the planets in this sample are likely to orbit in the circumstellar habitable zone. We determine that four candidate planets (KOI 854.01, 1298.02, 1686.01, and 2992.01) are inside of or within 1{sigma} of a conservative definition of the habitable zone, but that several planets identified by previous analyses are not (e.g., KOI 1422.02 and KOI 2626.01). Only one of the four habitable-zone planets is Earth sized, suggesting a downward revision in the occurrence of such planets around M dwarfs. These findings highlight the importance of measuring accurate stellar parameters when deriving parameters of their orbiting planets.
