- ID:
- ivo://CDS.VizieR/J/ApJ/803/69
- Title:
- Kepler planetary host stars rotation periods
- Short Name:
- J/ApJ/803/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyzed the host stars of the present sample of confirmed planets detected by Kepler and Kepler Objects of Interest to compute new photometric rotation periods and to study the behavior of their angular momentum. Lomb-Scargle periodograms and wavelet maps were computed for 3807 stars. For 540 of these stars, we were able to detect rotational modulation of the light curves at a significance level of greater than 99%. For 63 of these 540 stars, no rotation measurements were previously available in the literature. According to the published masses and evolutionary tracks of the stars in this sample, the sample is composed of M- to F-type stars (with masses of 0.48-1.53M_{sun}_) with rotation periods that span a range of 2-89 days. These periods exhibit an excellent agreement with those previously reported (for the stars for which such values are available), and the observed rotational period distribution strongly agrees with theoretical predictions. Furthermore, for the 540 sources considered here, the stellar angular momentum provides an important test of Kraft's relation based on the photometric rotation periods. Finally, this study directly contributes in a direct approach to our understanding of how angular momentum is distributed between the host star and its (detected) planetary system; the role of angular momentum exchange in such systems is an unavoidable piece of the stellar rotation puzzle.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/880/L1
- Title:
- Kepler planet masses, radii and orbital periods
- Short Name:
- J/ApJ/880/L1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Structure in the planet distribution provides an insight into the processes that shape the formation and evolution of planets. The Kepler mission has led to an abundance of statistical discoveries in regards to planetary radius, but the number of observed planets with measured masses is much smaller. By incorporating results from recent mass determination programs, we have discovered a new gap emerging in the planet population for sub-Neptune-mass planets with orbital periods less than 20 days. The gap follows a slope of decreasing mass with increasing orbital period, has a width of a few M_{Earth}_, and is potentially completely devoid of planets. Fitting Gaussian mixture models to the planet population in this region favors a bimodel distribution over a unimodel one with a reduction in Bayesian information criterion of 19.9, highlighting the gap significance. We discuss several processes that could generate such a feature in the planet distribution, including a pileup of planets above the gap region, tidal interactions with the host star, dynamical interactions with the disk, with other planets, or with accreting material during the formation process.
- ID:
- ivo://CDS.VizieR/J/ApJ/787/80
- Title:
- 139 Kepler planets transit time variations
- Short Name:
- J/ApJ/787/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extract densities and eccentricities of 139 sub-Jovian planets by analyzing transit time variations (TTVs) obtained by the Kepler mission through Quarter 12. We partially circumvent the degeneracies that plague TTV inversion with the help of an analytical formula for the TTV. From the observed TTV phases, we find that most of these planets have eccentricities of the order of a few percent. More precisely, the rms eccentricity is 0.018_-0.004_^+0.005^, and planets smaller than 2.5 R_{earth}_ are around twice as eccentric as those bigger than 2.5 R_{earth}_. We also find a best-fit density-radius relationship {rho}~3 g/cm^3^x(R/3 R_{earth}_)^-2.3^ for the 56 planets that likely have small eccentricity and hence small statistical correction to their masses. Many planets larger than 2.5 R_{earth}_are less dense than water, implying that their radii are largely set by a massive hydrogen atmosphere.
- ID:
- ivo://CDS.VizieR/J/AJ/152/105
- Title:
- Kepler-80 transit timing observations
- Short Name:
- J/AJ/152/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kepler has discovered hundreds of systems with multiple transiting exoplanets which hold tremendous potential both individually and collectively for understanding the formation and evolution of planetary systems. Many of these systems consist of multiple small planets with periods less than ~50 days known as Systems with Tightly spaced Inner Planets, or STIPs. One especially intriguing STIP, Kepler-80 (KOI-500), contains five transiting planets: f, d, e, b, and c with periods of 1.0, 3.1, 4.6, 7.1, and 9.5 days, respectively. We provide measurements of transit times and a transit timing variation (TTV) dynamical analysis. We find that TTVs cannot reliably detect eccentricities for this system, though mass estimates are not affected. Restricting the eccentricity to a reasonable range, we infer masses for the outer four planets (d, e, b, and c) to be 6.75_-0.51_^+0.69^, 4.13_-0.95_^+0.81^, 6.93_-0.70_^+1.05^, and 6.74_-0.86_^+1.23^ Earth masses, respectively. The similar masses but different radii are consistent with terrestrial compositions for d and e and ~2% H/He envelopes for b and c. We confirm that the outer four planets are in a rare dynamical configuration with four interconnected three-body resonances that are librating with few degree amplitudes. We present a formation model that can reproduce the observed configuration by starting with a multi-resonant chain and introducing dissipation. Overall, the information-rich Kepler-80 planets provide an important perspective into exoplanetary systems.
- 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/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/A+A/632/A34
- Title:
- KiDS+VIKING-450 opt+NIR dataset
- Short Name:
- J/A+A/632/A34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the curation and verification of a new combined optical and near infrared dataset for cosmology and astrophysics, derived by combining ugri-band imaging from the Kilo-Degree Survey (KiDS) and ZYJHKs-band imaging from the VISTA Kilo degree Infrared Galaxy (VIKING) survey. This dataset is unrivaled in cosmological imaging surveys due to the combination of its area (458 deg2 before masking), depth (r<=25), and wavelength coverage (ugriZYJHKs). This combination of survey depth, area, and (most importantly) wavelength coverage allows significant reductions in systematic uncertainties (i.e. reductions of between 10% and 60% in bias, outlier rate, and scatter) in photometric-to-spectroscopic redshift comparisons, compared to the optical-only case at photo-z above 0.7. The complementarity between our optical and near infrared surveys means that over 80% of our sources, across all photo-z, have significant detections (i.e. not upper limits) in our eight reddest bands. We have derived photometry, photo-z, and stellar masses for all sources in the survey, and verified these data products against existing spectroscopic galaxy samples. We demonstrate the fidelity of our higher-level data products by constructing the survey stellar mass functions in eight volume-complete redshift bins. We find that these photometrically derived mass functions provide excellent agreement with previous mass evolution studies derived using spectroscopic surveys. The primary data products presented in this paper are made publicly available through the KiDS survey website.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/858/118
- Title:
- Kinematic data of 3 nearby low-mass galaxies
- Short Name:
- J/ApJ/858/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of the nuclear star clusters (NSCs) and massive black holes (BHs) of four of the nearest low-mass early-type galaxies: M32, NGC 205, NGC 5102, and NGC 5206. We measure the dynamical masses of both the BHs and NSCs in these galaxies using Gemini/NIFS or VLT/SINFONI stellar kinematics, Hubble Space Telescope (HST) imaging, and Jeans anisotropic models. We detect massive BHs in M32, NGC 5102, and NGC 5206, while in NGC 205, we find only an upper limit. These BH mass estimates are consistent with previous measurements in M32 and NGC 205, while those in NGC 5102 and NGC 5206 are estimated for the first time and both found to be <10^6^M_{sun}_. This adds to just a handful of galaxies with dynamically measured sub-million M_{sun}_ central BHs. Combining these BH detections with our recent work on NGC 404's BH, we find that 80% (4/5) of nearby, low-mass (10^9^-10^10^M_{sun}_; {sigma}_*_~20-70km/s) early-type galaxies host BHs. Such a high occupation fraction suggests that the BH seeds formed in the early epoch of cosmic assembly likely resulted in abundant seeds, favoring a low-mass seed mechanism of the remnants, most likely from the first generation of massive stars. We find dynamical masses of the NSCs ranging from 2 to 73x10^6^M_{sun}_ and compare these masses to scaling relations for NSCs based primarily on photometric mass estimates. Color gradients suggest that younger stellar populations lie at the centers of the NSCs in three of the four galaxies (NGC 205, NGC 5102, and NGC 5206), while the morphology of two are complex and best fit with multiple morphological components (NGC 5102 and NGC 5206). The NSC kinematics show they are rotating, especially in M32 and NGC 5102 (V/{sigma}_*_~0.7).
- ID:
- ivo://CDS.VizieR/J/ApJ/867/93
- Title:
- Kinematic data of YNMGs from RAVE & Gaia
- Short Name:
- J/ApJ/867/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The purpose of this study is the identification of young (1<age<100Myr), nearby (d<=100pc) moving groups (YNMGs) through their kinematic signature. YNMGs could be the result of the recent dispersal of young embedded clusters, such that they still represent kinematically cold groups, carrying the residual motion of their parental cloud. Using the fact that a large number (~14000) of the RAVE sources with evidence of chromospheric activity also present signatures of stellar youth, we selected a sample of solar-type sources with the highest probability of chromospheric activity to look for common kinematics. We made use of radial velocity information from RAVE and astrometric parameters from GAIA DR2 to construct a 6D position-velocity vector catalog for our full sample. We developed a method based on the grouping of stars with similar orientation of their velocity vectors, which we call the Cone Method Sampling. Using this method, we detected 646 sources with high significance in the velocity space, with respect to the average orientation of artificial distributions made from a purely Gaussian velocity ellipsoid with null vertex deviation. We compared this sample of highly significant sources with a catalog of YNMGs reported in previous studies, which yield 75 confirmed members. From the remaining sample, about 50% of the sources have ages younger than 100Myr, which indicate they are highly probable candidates to be new members of identified or even other YNMGs in the solar neighborhood.
