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3291. Kepler-13AB aperture photometry
ID:
ivo://CDS.VizieR/J/AJ/158/113
Title:
Kepler-13AB aperture photometry
Short Name:
J/AJ/158/113
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the high-resolution imaging instrument, 'Alopeke, at the Gemini-N telescope, we obtained simultaneous two-channel time-series observations of the binary exoplanet host star Kepler13-AB. Our optical observations were obtained during a transit event of the exoplanet Kepler-13b and light curves were produced using both speckle interferometric and aperture photometry techniques. Both techniques confirm that the transiting object orbits the star Kepler-13A while different transit depths are seen across the optical wavelength range, being ~2 times deeper in the blue. These measurements, as well as mass determinations in the literature, are consistent with Kepler-13b being a highly irradiated gas giant with a bloated atmosphere. Our observations highlight the ability of high-resolution speckle imaging to not only assess binarity in exoplanet host stars but robustly determine which of the stars the transiting object actually orbits.
3292. Kepler-410Ab transit timing variations
ID:
ivo://CDS.VizieR/J/MNRAS/469/2907
Title:
Kepler-410Ab transit timing variations
Short Name:
J/MNRAS/469/2907
Date:
21 Oct 2021
Publisher:
CDS
Description:
For the determination of the individual times of transit we used short- cadence (sampled every 58.8 seconds) de-trended data (PDCSAP_FLUX) from quarters Q1 to Q17, provided by the NASA Exoplanet Archive. As a first step, we extracted parts of the LC around detected transits using the ephemeris given in Van Eylen et al. (2014ApJ...782...14V), where we took an interval 0.2 days around the computed transit time (the interval size is approximately double the transit duration). To remove additional residual trends caused by the stellar activity and instrumental long-term photometric variation, we fitted the out-of-transit part of LC by a second-order polynomial function. Then we subtracted 8% flux contamination from the wide companion Kepler-410B, according to calculations of Van Eylen et al. (2014ApJ...782...14V). All individual parts of the LC with transits were stacked together to obtain the template of the transit. The stacked LC was fitted by our software implementation of Mandel & Agol (2002ApJ...580L.117M) model, where we used theMarkov Chain Monte Carlo (MCMC) simulation method for the determination of transit parameters. This method takes into account individual errors of Kepler observations and gives a realistic and statistically significant estimate of parameter errors. As a starting point for the MCMC fitting, we used the physical parameters of the planet given in Van Eylen et al. (2014ApJ...782...14V). We have adopted a fixed value a=0.1226AU. We have used a quadratic model of limb darkening with starting values of coefficients from Sing (2010, Cat. J/A+A/510/A21). We ran the MCMC simulation with 10^6^ steps. We have repeated the MCMC simulation with the previous solution as the starting point on each of 70 individual transit intervals, and let only the time of transit to update. The new values were used to improve the linear ephemeris and to construct a new O-C diagram. The combined light curve stacked using a linear ephemeris is affected by relatively large amplitude of O-C time shifts. To correct this effect, we used iterative procedure that takes the best-fit O-C values into account. Afterwards, a new stacked light curve was constructed and a new MCMC transit solution was calculated, subsequently a new ephemeris and O-C values were determined. This process was repeated three times until a convergent solution was reached.
3293. Kepler asteroseismic targets
ID:
ivo://CDS.VizieR/J/MNRAS/412/1210
Title:
Kepler asteroseismic targets
Short Name:
J/MNRAS/412/1210
Date:
21 Oct 2021
Publisher:
CDS
Description:
Stellar structure and evolution can be studied in great detail by asteroseismic methods, provided data of high precision are available. We determine the effective temperature (Teff), surface gravity (logg), metallicity, and the projected rotational velocity (vsini) of 44 Kepler asteroseismic targets using our high-resolution (R>20000) spectroscopic observations; these parameters will then be used to compute asteroseismic models of these stars and to interpret the Kepler light curves.We use the method of cross correlation to measure the radial velocity (RV) of our targets, while atmospheric parameters are derived using the ROTFIT code and spectral synthesis method.
3294. Kepler compact pulsator candidates
ID:
ivo://CDS.VizieR/J/MNRAS/409/1470
Title:
Kepler compact pulsator candidates
Short Name:
J/MNRAS/409/1470
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from the first two quarters of a survey to search for pulsations in compact stellar objects with the Kepler spacecraft. The survey sample and the various methods applied in its compilation are described, and spectroscopic observations are presented to separate the objects into accurate classes. From the Kepler photometry we clearly identify nine compact pulsators and a number of interesting binary stars.
3295. Kepler compact pulsator candidates
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.
3296. Kepler cycle 1 observations of low-mass stars
ID:
ivo://CDS.VizieR/J/AJ/143/4
Title:
Kepler cycle 1 observations of low-mass stars
Short Name:
J/AJ/143/4
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have analyzed Kepler light curves for 849 stars with Teff<=5200K from our Cycle 1 Guest Observer program. We identify six new eclipsing binaries, one of which has an orbital period of 29.91 days and two of which are probably W UMa variables. In addition, we identify a candidate "warm Jupiter" exoplanet. We further examine a subset of 670 sources for variability. Of these objects, 265 stars clearly show periodic variability that we assign to rotation of the low-mass star. At the photometric precision level provided by Kepler, 251 of our objects showed no evidence for variability. We were unable to determine periods for 154 variable objects. We find that 79% of stars with Teff<=5200K are variable. The rotation periods we derive for the periodic variables span the range 0.31days<=Prot<=126.5days. A considerable number of stars with rotation periods similar to the solar value show activity levels that are 100 times higher than the Sun.
3297. Kepler eclipse timings of KIC 9472174
ID:
ivo://CDS.VizieR/J/ApJ/753/101
Title:
Kepler eclipse timings of KIC 9472174
Short Name:
J/ApJ/753/101
Date:
21 Oct 2021
Publisher:
CDS
Description:
The eclipsing binary system 2M 1938+4603 consists of a pulsating hot subdwarf B star and a cool M dwarf companion in an effectively circular three-hour orbit. The light curve shows both primary and secondary eclipses, along with a strong reflection effect from the cool companion. Here, we present constraints on the component masses and eccentricity derived from the Romer delay of the secondary eclipse. Using six months of publicly available Kepler photometry obtained in short-cadence mode, we fit model profiles to the primary and secondary eclipses to measure their centroid values. We find that the secondary eclipse arrives on average 2.06+/-0.12s after the midpoint between primary eclipses. Under the assumption of a circular orbit, we calculate from this time delay a mass ratio of q=0.2691+/-0.0018 and individual masses of M_sd_=0.372+/-0.024M_{sun}_ and M_c_=0.1002+/-0.0065M_{sun}_ for the sdB and M dwarf, respectively. These results differ slightly from those of a previously published light-curve modeling solution; this difference, however, may be reconciled with a very small eccentricity, ecos{omega}{approx}0.00004. We also report a decrease in the orbital period of \dot{P}=(-1.23+/-0.07)x10^-10^.
3298. Kepler follow-up observation program. I. Imaging
ID:
ivo://CDS.VizieR/J/AJ/153/71
Title:
Kepler follow-up observation program. I. Imaging
Short Name:
J/AJ/153/71
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from high-resolution, optical to near-IR imaging of host stars of Kepler Objects of Interest (KOIs), identified in the original Kepler field. Part of the data were obtained under the Kepler imaging follow-up observation program over six years (2009-2015). Almost 90% of stars that are hosts to planet candidates or confirmed planets were observed. We combine measurements of companions to KOI host stars from different bands to create a comprehensive catalog of projected separations, position angles, and magnitude differences for all detected companion stars (some of which may not be bound). Our compilation includes 2297 companions around 1903 primary stars. From high-resolution imaging, we find that ~10% (~30%) of the observed stars have at least one companion detected within 1'' (4''). The true fraction of systems with close (<~4'') companions is larger than the observed one due to the limited sensitivities of the imaging data. We derive correction factors for planet radii caused by the dilution of the transit depth: assuming that planets orbit the primary stars or the brightest companion stars, the average correction factors are 1.06 and 3.09, respectively. The true effect of transit dilution lies in between these two cases and varies with each system. Applying these factors to planet radii decreases the number of KOI planets with radii smaller than 2R_{Earth}_ by ~2%-23% and thus affects planet occurrence rates. This effect will also be important for the yield of small planets from future transit missions such as TESS.
3299. Kepler light curve of the EB star KIC 9532219
ID:
ivo://CDS.VizieR/J/ApJ/820/1
Title:
Kepler light curve of the EB star KIC 9532219
Short Name:
J/ApJ/820/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
KIC 9532219 is a W UMa-type eclipsing binary with an orbital period of 0.1981549days that is below the short-period limit (~0.22days) of the period distribution for contact binaries. The Kepler light curve of the system exhibits striking changes in both eclipse depths and light maxima. Applying third-body and spot effects, the light-curve synthesis indicates that the eclipsing pair is currently in a marginal contact stage with a mass ratio of q=1.20, an orbital inclination of i=66.0{deg}, a temperature difference of T_1_-T_2_=172K, and a third light of l_3_=75.9%. To understand the light variations with time, we divided up the light curve into 312 segments and analyzed them separately. The results reveal that variation of eclipse depth is primarily caused by changing amounts of contamination due to the nearby star KIC 9532228 between the Kepler Quarters and that the variable O'Connell effect originates from the starspot activity on the less massive primary component. Based on our light-curve timings, a period study of KIC 9532219 indicates that the orbital period has varied as a combination of a downward parabola and a light-travel-time (LTT) effect due to a third body, which has a period of 1196 days and a minimum mass of 0.0892M_{sun}_ in an orbit of eccentricity 0.150. The parabolic variation could be a small part of a second LTT orbit due to a fourth component in a wider orbit, instead of either mass transfer or angular momentum loss.
3300. Kepler light curves of Jovian Trojan asteroids
ID:
ivo://CDS.VizieR/J/ApJS/254/7
Title:
Kepler light curves of Jovian Trojan asteroids
Short Name:
J/ApJS/254/7
Date:
21 Oct 2021
Publisher:
CDS
Description:
Various properties of Jovian Trojan asteroids such as composition, rotation periods, and photometric amplitudes, or the rate of binarity in the population, can provide information and constraints on the evolution of the group and of the solar system itself. Here we present new photometric properties of 45 Jovian Trojans from the K2 mission of the Kepler space telescope, and present phase-folded light curves for 44 targets, including (11351) Leucus, one of the targets of the Lucy mission. We extend our sample to 101 asteroids with previous K2 Trojan measurements, then compare their combined amplitude and frequency distributions to other ground-based and space data. We show that there is a dichotomy in the periods of Trojans with a separation at ~100hr. We find that 25% of the sample are slow rotators (P>=30hr), an excess that can be attributed to binary objects. We also show that 32 systems can be classified as potential detached binary systems. Finally, we calculate density and rotation constraints for the asteroids. Both the spin barrier and fits to strengthless ellipsoid models indicate low densities and thus compositions similar to populations of comets and trans-Neptunian objects throughout the sample. This supports the scenario of outer solar system origin for Jovian Trojans.