- ID:
- ivo://CDS.VizieR/J/ApJS/224/2
- Title:
- K2 EPIC stellar properties for 138600 targets
- Short Name:
- J/ApJS/224/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The K2 Mission uses the Kepler spacecraft to obtain high-precision photometry over ~80 day campaigns in the ecliptic plane. The Ecliptic Plane Input Catalog (EPIC) provides coordinates, photometry, and kinematics based on a federation of all-sky catalogs to support target selection and target management for the K2 mission. We describe the construction of the EPIC, as well as modifications and shortcomings of the catalog. Kepler magnitudes (Kp) are shown to be accurate to ~0.1mag for the Kepler field, and the EPIC is typically complete to Kp~17 (Kp~19 for campaigns covered by Sloan Digital Sky Survey). We furthermore classify 138600 targets in Campaigns 1-8 (~88% of the full target sample) using colors, proper motions, spectroscopy, parallaxes, and galactic population synthesis models, with typical uncertainties for G-type stars of ~3% in Teff, ~0.3dex in logg~40% in radius, ~10% in mass, and ~40% in distance. Our results show that stars targeted by K2 are dominated by K-M dwarfs (~41% of all selected targets), F-G dwarfs (~36%), and K giants (~21%), consistent with key K2 science programs to search for transiting exoplanets and galactic archeology studies using oscillating red giants. However, we find significant variation of the fraction of cool dwarfs with galactic latitude, indicating a target selection bias due to interstellar reddening and increased contamination by giant stars near the galactic plane. We discuss possible systematic errors in the derived stellar properties, and differences with published classifications for K2 exoplanet host stars.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/2860
- Title:
- Kepler compact pulsator candidates
- Short Name:
- J/MNRAS/414/2860
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the final 6 months of a survey to search for pulsations in white dwarfs (WDs) and hot subdwarf stars with the Kepler spacecraft. Spectroscopic observations are used to separate the objects into accurate classes, and we explore the physical parameters of the subdwarf B (sdB) stars and white dwarfs in the sample. From the Kepler photometry and our spectroscopic data, we find that the sample contains five new pulsators of the V1093 Her type, one AM CVn type cataclysmic variable and a number of other binary systems.
- ID:
- ivo://CDS.VizieR/J/AJ/141/83
- Title:
- Kepler Mission. I. Eclipsing binaries in DR1
- Short Name:
- J/AJ/141/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105deg^2^ field of view features over 156,000 stars that are observed continuously to detect and characterize planet transits. Yet, this high-precision instrument holds great promise for other types of objects as well. Here we present a comprehensive catalog of eclipsing binary stars observed by Kepler in the first 44 days of operation, the data being publicly available through MAST as of 2010 June 15. The catalog contains 1879 unique objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/736/19
- Title:
- Kepler planetary candidates. II.
- Short Name:
- J/ApJ/736/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On 2011 February 1 the Kepler mission released data for 156453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates are separated into five class sizes: 68 candidates of approximately Earth-size (R_p_<1.25R_{earth}_), 288 super-Earth-size (1.25R_{earth}_<=R_p_<2R_{earth}_), 662 Neptune-size (2R_{earth}_<=R_p_<6R_{earth}_), 165 Jupiter-size (6R_{earth}<=R_p_<15R_{earth}_), and 19 up to twice the size of Jupiter (15R_{earth}_<=R_p_<22R_{earth}_). In the temperature range appropriate for the habitable zone, 54 candidates are found with sizes ranging from Earth-size to larger than that of Jupiter. Six are less than twice the size of the Earth. Over 74% of the planetary candidates are smaller than Neptune. Multi-candidate, transiting systems are frequent; 17% of the host stars have multi-candidate systems, and 34% of all the candidates are part of multi-candidate systems.
- 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).
- 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/ApJ/884/4
- Title:
- KEYSTONE: ammonia structures in Galactic GMCs
- Short Name:
- J/ApJ/884/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present initial results from the K-band Focal Plane Array Examinations of Young STellar Object Natal Environments survey (KEYSTONE), a large project on the 100m Green Bank Telescope mapping ammonia emission across 11 giant molecular clouds at distances of 0.9-3.0kpc (Cygnus X North, Cygnus X South, M16, M17, Mon R1, Mon R2, NGC 2264, NGC 7538, Rosette, W3, and W48). This data release includes the NH_3_ (1,1) and (2,2) maps for each cloud, which are modeled to produce maps of kinetic temperature, centroid velocity, velocity dispersion, and ammonia column density. Median cloud kinetic temperatures range from 11.4+/-2.2K in the coldest cloud (Mon R1) to 23.0+/-6.5K in the warmest cloud (M17). Using dendrograms on the NH_3_ (1,1) integrated intensity maps, we identify 856 dense gas clumps across the 11 clouds. Depending on the cloud observed, 40%-100% of the clumps are aligned spatially with filaments identified in H2 column density maps derived from spectral energy distribution fitting of dust continuum emission. A virial analysis reveals that 523 of the 835 clumps (~63%) with mass estimates are bound by gravity alone. We find no significant difference between the virial parameter distributions for clumps aligned with the dust-continuum filaments and those unaligned with filaments. In some clouds, however, hubs or ridges of dense gas with unusually high mass and low virial parameters are located within a single filament or at the intersection of multiple filaments. These hubs and ridges tend to host water maser emission, multiple 70{mu}m detected protostars, and have masses and radii above an empirical threshold for forming massive stars.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A83
- Title:
- K2-Gaia-ESO stellar param. and abundances
- Short Name:
- J/A+A/643/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The extensive stellar spectroscopic datasets that are available for studies in Galactic Archeaology thanks to, for example, the Gaia-ESO Survey, now benefit from having a significant number of targets that overlap with asteroseismology projects such as Kepler, K2, and CoRoT. Combining the measurements from spectroscopy and asteroseismology allows us to attain greater accuracy with regard to the stellar parameters needed to characterise the stellar populations of the Milky Way. The aim of this Gaia-ESO Survey special project is to produce a catalogue of self-consistent stellar parameters by combining measurements from high- resolution spectroscopy and precision asteroseismology. We carried out an iterative analysis of 90 K2@Gaia-ESO red giants. The spectroscopic values of Teff were used as input in the seismic analysis to obtain logg values. The seismic estimates of logg were then used to re- determine the spectroscopic values of Teff and [Fe/H]. Only one iteration was required to obtain parameters that are in good agreement for both methods and, thus, to obtain the final stellar parameters. A detailed analysis of outliers was carried out to ensure a robust determination of the parameters. The results were then combined with Gaia DR2 data to compare the seismic log g with a parallax-based log g and to investigate instances of variations in the velocity and possible binaries within the dataset. This analysis produced a high-quality catalogue of stellar parameters for 90 red giant stars from K2@Gaia-ESO that were determined through iterations between spectroscopy and asteroseismology. We compared the seismic gravities with those based on Gaia parallaxes to find an offset which is similar to other studies that have used asteroseismology. Our catalogue also includes spectroscopic chemical abundances and radial velocities, as well as indicators for possible binary detections.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/83
- Title:
- K2 GAP data release. I. Campaign 1
- Short Name:
- J/ApJ/835/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NASA's K2 mission is observing tens of thousands of stars along the ecliptic, providing data suitable for large-scale asteroseismic analyses to inform galactic archaeology studies. Its first campaign covered a field near the north Galactic cap, a region never covered before by large asteroseismic-ensemble investigations, and was therefore of particular interest for exploring this part of our Galaxy. Here we report the asteroseismic analysis of all stars selected by the K2 Galactic Archaeology Program during the mission's "north Galactic cap" campaign 1. Our consolidated analysis uses six independent methods to measure the global seismic properties, in particular the large frequency separation and the frequency of maximum power. From the full target sample of 8630 stars we find about 1200 oscillating red giants, a number comparable with estimates from galactic synthesis modeling. Thus, as a valuable by-product we find roughly 7500 stars to be dwarfs, which provide a sample well suited for galactic exoplanet occurrence studies because they originate from our simple and easily reproducible selection function.
