- ID:
- ivo://CDS.VizieR/J/ApJS/204/24
- Title:
- Kepler planetary candidates. III.
- Short Name:
- J/ApJS/204/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New transiting planet candidates are identified in 16 months (2009 May-2010 September) of data from the Kepler spacecraft. Nearly 5000 periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1108 viable new planet candidates, bringing the total count up to over 2300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multi-quarter photo-center offsets derived from difference image analysis that identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the candidates. Ephemerides (transit epoch, T_0_, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (R_P_/R_*_), reduced semimajor axis (d/R_*_), and impact parameter (b).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/210/19
- Title:
- Kepler planetary candidates. IV. 22 months
- Short Name:
- J/ApJS/210/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2738 Kepler planet candidates distributed across 2017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ~40% of the sample with R_P_~1R_{oplus}_ and represent ~40% of the low equilibrium temperature (T_eq_<30 K) sample. We review the known biases in the current sample of Kepler planet candidates relevant to evaluating planet population statistics with the current Kepler planet candidate sample.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/12
- Title:
- Kepler planetary candidates. VII. 48-month
- Short Name:
- J/ApJS/224/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the seventh Kepler planet candidate (PC) catalog, which is the first catalog to be based on the entire, uniformly processed 48-month Kepler data set. This is the first fully automated catalog, employing robotic vetting procedures to uniformly evaluate every periodic signal detected by the Q1-Q17 Data Release 24 (DR24) Kepler pipeline. While we prioritize uniform vetting over the absolute correctness of individual objects, we find that our robotic vetting is overall comparable to, and in most cases superior to, the human vetting procedures employed by past catalogs. This catalog is the first to utilize artificial transit injection to evaluate the performance of our vetting procedures and to quantify potential biases, which are essential for accurate computation of planetary occurrence rates. With respect to the cumulative Kepler Object of Interest (KOI) catalog, we designate 1478 new KOIs, of which 402 are dispositioned as PCs. Also, 237 KOIs dispositioned as false positives (FPs) in previous Kepler catalogs have their disposition changed to PC and 118 PCs have their disposition changed to FPs. This brings the total number of known KOIs to 8826 and PCs to 4696. We compare the Q1-Q17 DR24 KOI catalog to previous KOI catalogs, as well as ancillary Kepler catalogs, finding good agreement between them. We highlight new PCs that are both potentially rocky and potentially in the habitable zone of their host stars, many of which orbit solar-type stars. This work represents significant progress in accurately determining the fraction of Earth-size planets in the habitable zone of Sun-like stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/235/38
- Title:
- Kepler planetary cand. VIII. DR25 reliability
- Short Name:
- J/ApJS/235/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Kepler Object of Interest (KOI) catalog of transiting exoplanets based on searching 4yr of Kepler time series photometry (Data Release 25, Q1-Q17: Twicken+, 2016, J/AJ/152/158). The catalog contains 8054 KOIs, of which 4034 are planet candidates with periods between 0.25 and 632 days. Of these candidates, 219 are new, including two in multiplanet systems (KOI-82.06 and KOI-2926.05) and 10 high-reliability, terrestrial-size, habitable zone candidates. This catalog was created using a tool called the Robovetter, which automatically vets the DR25 threshold crossing events (TCEs). The Robovetter also vetted simulated data sets and measured how well it was able to separate TCEs caused by noise from those caused by low signal-to-noise transits. We discuss the Robovetter and the metrics it uses to sort TCEs. For orbital periods less than 100 days the Robovetter completeness (the fraction of simulated transits that are determined to be planet candidates) across all observed stars is greater than 85%. For the same period range, the catalog reliability (the fraction of candidates that are not due to instrumental or stellar noise) is greater than 98%. However, for low signal-to-noise candidates between 200 and 500 days around FGK-dwarf stars, the Robovetter is 76.7% complete and the catalog is 50.5% reliable.
- 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_.
- 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/ApJ/787/47
- Title:
- 106 Kepler ultra-short-period planets
- Short Name:
- J/ApJ/787/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a survey aimed at discovering and studying transiting planets with orbital periods shorter than one day (ultra-short-period, or USP, planets), using data from the Kepler spacecraft. We computed Fourier transforms of the photometric time series for all 200000 target stars, and detected transit signals based on the presence of regularly spaced sharp peaks in the Fourier spectrum. We present a list of 106 USP candidates, of which 18 have not previously been described in the literature. This list of candidates increases the number of planet candidates with orbital periods shorter than about six hours from two to seven. In addition, among the objects we studied, there are 26 USP candidates that had been previously reported in the literature which do not pass our various tests. All 106 of our candidates have passed several standard tests to rule out false positives due to eclipsing stellar systems. A low false positive rate is also implied by the relatively high fraction of candidates for which more than one transiting planet signal was detected. By assuming these multi-transit candidates represent coplanar multi-planet systems, we are able to infer that the USP planets are typically accompanied by other planets with periods in the range 1-50 days, in contrast with hot Jupiters which very rarely have companions in that same period range. Another clear pattern is that almost all USP planets are smaller than 2 R_{earth}_, possibly because gas giants in very tight orbits would lose their atmospheres by photoevaporation when subject to extremely strong stellar irradiation. Based on our survey statistics, USP planets exist around approximately (0.51+/-0.07)% of G-dwarf stars, and (0.83+/-0.18)% of K-dwarf stars.
- ID:
- ivo://CDS.VizieR/J/AJ/112/171
- Title:
- K Giants in Baade's Window. II
- Short Name:
- J/AJ/112/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second in a series of papers in which we analyze spectra of over 400 K and M giants in Baade's Window, including most of the stars with proper motions measured by Spaenhauer et al. (1992AJ....103..297S). In our first paper, we measured line-strength indices of Fe, Mg, CN, and HBeta and calibrated them on the system of Faber et al. (1985ApJS...57..711F). Here, we use the <Fe> index to derive an abundance distribution of [Fe/H] for 322 stars with effective temperatures between 3900K and 5160K. Our derived values of [Fe/H] agree well with those measured from high-resolution echelle spectra (e.g., McWilliam & Rich, 1994ApJS...91..749M) for the small number of stars in common. We find a mean abundance <[Fe/H]>=-0.11+/-0.04 for our sample of Baade's Window K giants. More than half the sample lie in the range -0.4<[Fe/H]<+0.3. We estimate line-of-sight distances for individual stars in our sample and confirm that, in Baade's Window, most K giants with V<15.5 are foreground disk stars, but the great majority (more than 80%) with V>16 belong to the bulge. We also compare the metallicities derived from the CN and Mg2 indices to those from iron. Most of the metal-rich stars in our sample appear to be CN-weak, in contrast to the situation in metal-rich globular clusters and elliptical galaxies. The metal-poor half of our sample ([Fe/H]<0) shows evidence for a mild Mg overenhancement ([Mg/Fe]~+0.2); but this is not seen in the more metal-rich stars ([Fe/H]>=0). The K giants in Baade's Window therefore share some, but not all, of the characteristics of stars in elliptical galaxies as inferred from their integrated light.
- ID:
- ivo://CDS.VizieR/J/ApJ/729/L10
- Title:
- KIC stars properties in NGC 6791 and NGC 6819
- Short Name:
- J/ApJ/729/L10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present initial results on some of the properties of open clusters NGC 6791 and NGC 6819 derived from asteroseismic data obtained by NASA's Kepler mission. In addition to estimating the mass, radius, and log g of stars on the red giant branch (RGB) of these clusters, we estimate the distance to the clusters and their ages. Our model-independent estimate of the distance modulus of NGC 6791 is (m-M)_0_=13.11+/-0.06. We find (m-M)_0_=11.85+/-0.05 for NGC 6819. The average mass of stars on the RGB of NGC 6791 is 1.20+/-0.01M_{sun}_, while that of NGC 6819 is 1.68+/-0.03M_{sun}_. It should be noted that we do not have data that cover the entire RGB and the actual mass will be somewhat lower. We have determined model-dependent estimates of ages of these clusters. We find ages between 6.8 and 8.6Gyr for NGC 6791, however, most sets of models give ages around 7Gyr. We obtain ages between 2 and 2.4Gyr for NGC 6819.
- ID:
- ivo://CDS.VizieR/J/ApJS/225/10
- Title:
- Kinematic analysis of M7-L8 dwarfs
- Short Name:
- J/ApJS/225/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a kinematic analysis of 152 low surface gravity M7-L8 dwarfs by adding 18 new parallaxes (including 10 for comparative field objects), 38 new radial velocities, and 19 new proper motions. We also add low- or moderate-resolution near-infrared spectra for 43 sources confirming their low surface gravity features. Among the full sample, we find 39 objects to be high-likelihood or new bona fide members of nearby moving groups, 92 objects to be ambiguous members and 21 objects that are non-members. Using this age-calibrated sample, we investigate trends in gravity classification, photometric color, absolute magnitude, color-magnitude, luminosity, and effective temperature.
