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71. KELT transit false positive catalog for TESS
ID:
ivo://CDS.VizieR/J/AJ/156/234
Title:
KELT transit false positive catalog for TESS
Short Name:
J/AJ/156/234
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Kilodegree Extremely Little Telescope (KELT) project has been conducting a photometric survey of transiting planets orbiting bright stars for over 10 years. The KELT images have a pixel scale of ~23"/pixel very similar to that of NASA's Transiting Exoplanet Survey Satellite (TESS) - as well as a large point-spread function, and the KELT reduction pipeline uses a weighted photometric aperture with radius 3'. At this angular scale, multiple stars are typically blended in the photometric apertures. In order to identify false positives and confirm transiting exoplanets, we have assembled a follow-up network (KELT-FUN) to conduct imaging with spatial resolution, cadence, and photometric precision higher than the KELT telescopes, as well as spectroscopic observations of the candidate host stars. The KELT-FUN team has followed-up over 1600 planet candidates since 2011, resulting in more than 20 planet discoveries. Excluding ~450 false alarms of non-astrophysical origin (i.e., instrumental noise or systematics), we present an all-sky catalog of the 1128 bright stars (6<V<13) that show transit-like features in the KELT light curves, but which were subsequently determined to be astrophysical false positives (FPs) after photometric and/or spectroscopic follow-up observations. The KELT-FUN team continues to pursue KELT and other planet candidates and will eventually follow up certain classes of TESS candidates. The KELT FP catalog will help minimize the duplication of follow-up observations by current and future transit surveys such as TESS.
72. Kepler and K2 best candidates for planets
ID:
ivo://CDS.VizieR/J/MNRAS/465/2634
Title:
Kepler and K2 best candidates for planets
Short Name:
J/MNRAS/465/2634
Date:
21 Oct 2021
Publisher:
CDS
Description:
A crucial step in planet hunting surveys is to select the best candidates for follow-up observations, given limited telescope resources. This is often performed by human 'eyeballing', a time consuming and statistically awkward process. Here, we present a new, fast machine learning technique to separate true planet signals from astrophysical false positives. We use self-organizing maps (SOMs) to study the transit shapes of Kepler and K2 known and candidate planets. We find that SOMs are capable of distinguishing known planets from known false positives with a success rate of 87.0 per cent, using the transit shape alone. Furthermore, they do not require any candidate to be dispositioned prior to use, meaning that they can be used early in a mission's lifetime. A method for classifying candidates using a SOM is developed, and applied to previously unclassified members of the Kepler Objects of Interest (KOI) list as well as candidates from the K2 mission. The method is extremely fast, taking minutes to run the entire KOI list on a typical laptop. We make PYTHON code for performing classifications publicly available, using either new SOMs or those created in this work. The SOM technique represents a novel method for ranking planetary candidate lists, and can be used both alone or as part of a larger autovetting code.
73. Kepler-278 and Kepler-391 spectra
ID:
ivo://CDS.VizieR/J/A+A/634/A29
Title:
Kepler-278 and Kepler-391 spectra
Short Name:
J/A+A/634/A29
Date:
21 Oct 2021
Publisher:
CDS
Description:
Kepler-278 and Kepler-391 are two of the three evolved stars on the red giant branch (RGB) known to date, to host multiple short-period transiting planets. Moreover, these planets are among the smallest discovered around RGB stars. Here, we present a detailed stellar and planetary characterization of these remarkable systems. Methods. Based on high-quality spectra from Gemini-GRACES of Kepler-278 and Kepler-391, we obtained refined stellar parameters and precise chemical abundances of 25 elements. Nine of these elements and the carbon isotopic ratios, ^12^C/^13^C, were not previously measured. Also, combining our new stellar parameters with a photodynamical analysis of the Kepler light curves, we determined accurate planetary properties of both systems. Results. Our revised stellar parameters agree reasonably well with most of the previous results, although we find that Kepler-278 is ~15% less massive than previously reported. The abundances of C, N, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, and Ce, in both stars, are consistent with those of evolved nearby thin disk stars. Kepler-391 presents a relatively high abundance of lithium (A(Li)NLTE=1.29+/-0.09dex), which is likely a remnant from the main-sequence phase. The precise spectroscopic parameters of Kepler-278 and Kepler-391 along with their high 12 C/13 C ratios show that both stars are just starting their ascent on the RGB. The planets Kepler-278b, Kepler-278c, and Kepler-391c are warm sub-Neptunes, whilst Kepler-391b is a hot sub-Neptune that falls in the Hot Super-Earth desert and therefore it might be undergoing photo-evaporation of its outer envelope. The high-precision obtained in the transit times allowed us not only to confirm Kepler-278c's TTV signal but also to find evidence of a previously undetected TTV signal for the inner planet Kepler-278b. From the presence of gravitational interaction between these bodies we constrain, for the first time, the mass of Kepler-278b (Mp=56M_Earth_) and Kepler-278c (Mp=35M_Earth_). The mass limits, coupled with our precise determinations of the planetary radii, suggest that their bulk compositions are consistent with a significant amount of water content and the presence of H2 gaseous envelopes. Finally, our photodynamical analysis also shows that the orbits of both planets around Kepler-278 are highly eccentric (e~0.7) and, surprisingly, coplanar. Further observations (e.g., precise radial velocities) of this system are needed to confirm the eccentricity values presented here.
74. Kepler Confirmed Planets
ID:
ivo://archive.stsci.edu/kepler_planets
Title:
Kepler Confirmed Planets
Short Name:
Kepler Planets
Date:
22 Jul 2020 20:51:12
Publisher:
Space Telescope Science Institute Archive
Description:
The list of currently confirmed exoplanets discovered by Kepler (from data compiled by http://nexsci.caltech.edu).
75. Kepler Data Search
ID:
ivo://archive.stsci.edu/kepler
Title:
Kepler Data Search
Short Name:
Kepler CS
Date:
22 Jul 2020 21:17:20
Publisher:
Space Telescope Science Institute Archive
Description:
Launched in 2009, the Kepler Mission is surveying a region of our galaxy to determine what fraction of stars in our galaxy have planets and measure the size distribution of those exoplanets. Although Kepler completed its primary mission to determine the fraction of stars that have planets in 2013, it is continuing the search, using a more limited survey mode, under the new name K2. This service is the main Kepler data search.
76. Kepler Data Search
ID:
ivo://archive.stsci.edu/kepler_ktc
Title:
Kepler Data Search
Short Name:
KTC
Date:
22 Jul 2020 21:12:32
Publisher:
Space Telescope Science Institute Archive
Description:
This interface joins the Kepler Target Catalog (KTC) with other tables to allow users to access the Kepler data archive. Observed Kepler targets are included with their associated data set names. Since most of the Kepler light curve data is still proprietary, public data can be found by searching for release dates earlier than todays date.
77. Kepler GK dwarf planet candidate samples
ID:
ivo://CDS.VizieR/J/AJ/157/143
Title:
Kepler GK dwarf planet candidate samples
Short Name:
J/AJ/157/143
Date:
21 Oct 2021
Publisher:
CDS
Description:
We re-examine the statistical confirmation of small long-period Kepler planet candidates in light of recent improvements in our understanding of the occurrence of systematic false alarms in this regime. Using the final Data Release 25 (DR25, Twicken et al. 2016, J/AJ/152/158) Kepler planet candidate catalog statistics, we find that the previously confirmed single-planet system Kepler-452b no longer achieves a 99% confidence in the planetary hypothesis and is not considered statistically validated in agreement with the finding of Mullally et al. (2018AJ....155..210M). For multiple planet systems, we find that the planet prior enhancement for belonging to a multiple-planet system is suppressed relative to previous Kepler catalogs, and we also find that the multiple-planet system member, Kepler-186f, no longer achieves a 99% confidence level in the planetary hypothesis. Because of the numerous confounding factors in the data analysis process that leads to the detection and characterization of a signal, it is difficult to determine whether any one planetary candidate achieves a strict criterion for confirmation relative to systematic false alarms. For instance, when taking into account a simplified model of processing variations, the additional single-planet systems Kepler-443b, Kepler-441b, Kepler-1633b, Kepler-1178b, and Kepler-1653b have a non-negligible probability of falling below 99% confidence in the planetary hypothesis. The systematic false alarm hypothesis must be taken into account when employing statistical validation techniques in order to confirm planet candidates that approach the detection threshold of a survey. We encourage those performing transit searches of K2, TESS, and other similar data sets to quantify their systematic false alarm rates. Alternatively, independent photometric detection of the transit signal or radial velocity measurements can eliminate the false alarm hypothesis.
78. Kepler K2 Data Search Catalog
ID:
ivo://archive.stsci.edu/k2
Title:
Kepler K2 Data Search Catalog
Short Name:
K2
Date:
22 Jul 2020 21:33:57
Publisher:
Space Telescope Science Institute Archive
Description:
Launched in 2009, the Kepler Mission is surveying a region of our galaxy to determine what fraction of stars in our galaxy have planets and measure the size distribution of those exoplanets. Although Kepler completed its primary mission to determine the fraction of stars that have planets in 2013, it is continuing the search, using a more limited survey mode, under the new name K2. The K2 Data Search Service provides the main catalog for all K2 data.
79. Kepler K2 Ecliptic Plane Input Catalog
ID:
ivo://archive.stsci.edu/kepler/k2_epic
Title:
Kepler K2 Ecliptic Plane Input Catalog
Short Name:
K2 EPIC
Date:
12 Feb 2020 19:53:23
Publisher:
Space Telescope Science Institute Archive
Description:
Launched in 2009, the Kepler Mission is surveying a region of our galaxy to determine what fraction of stars in our galaxy have planets and measure the size distribution of those exoplanets. Although Kepler completed its primary mission to determine the fraction of stars that have planets in 2013, it is continuing the search, using a more limited survey mode, under the new name K2. The K2 Ecliptic Plane Input Catalog is the primary source of information about objects observed as potential targets for the K2 mission, as the Kepler Input Catalog was used for the original Kepler mission.
80. Kepler M dwarf stars revised properties
ID:
ivo://CDS.VizieR/J/MNRAS/457/2877
Title:
Kepler M dwarf stars revised properties
Short Name:
J/MNRAS/457/2877
Date:
21 Oct 2021
Publisher:
CDS
Description:
We classified the reddest (r-J>2.2) stars observed by the NASA Kepler mission into main-sequence dwarf or evolved giant stars and determined the properties of 4216 M dwarfs based on a comparison of available photometry with that of nearby calibrator stars, as well as available proper motions and spectra. We revised the properties of candidate transiting planets using the stellar parameters, high-resolution imaging to identify companion stars, and, in the case of binaries, fitting light curves to identify the likely planet host. In 49 of 54 systems, we validated the primary as the host star. We inferred the intrinsic distribution of M dwarf planets using the method of iterative Monte Carlo simulation. We compared several models of planet orbital geometry and clustering and found that one where planets are exponentially distributed and almost precisely coplanar best describes the distribution of multiplanet systems. We determined that Kepler M dwarfs host an average of 2.2+/-0.3 planets with radii of 1-4R_{Earth}_ and orbital periods of 1.5-180d. The radius distribution peaks at ~1.2R_{Earth}_ and is essentially zero at 4R_{Earth}_, although we identify three giant planet candidates other than the previously confirmed Kepler-45b. There is suggestive but not significant evidence that the radius distribution varies with orbital period. The distribution with logarithmic orbital period is flat except for a decline for orbits less than a few days. 12 candidate planets, including two Jupiter-size objects, experience an irradiance below the threshold level for a runaway greenhouse on an Earth-like planet and are thus in a 'habitable zone'.