- ID:
- ivo://CDS.VizieR/J/AJ/155/21
- Title:
- Planet candidates from K2 campaigns 5-8
- Short Name:
- J/AJ/155/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 151 planet candidates orbiting 141 stars from K2 campaigns 5-8 (C5-C8), identified through a systematic search of K2 photometry. In addition, we identify 16 targets as likely eclipsing binaries, based on their light curve morphology. We obtained follow-up optical spectra of 105/141 candidate host stars and 8/16 eclipsing binaries to improve stellar properties and to identify spectroscopic binaries. Importantly, spectroscopy enables measurements of host star radii with ~10% precision, compared to ~40% precision when only broadband photometry is available. The improved stellar radii enable improved planet radii. Our curated catalog of planet candidates provides a starting point for future efforts to confirm and characterize K2 discoveries.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/465/2734
- Title:
- Planet-hosting solar-type stars magnetic fields
- Short Name:
- J/MNRAS/465/2734
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectropolarimetric snapshot survey of solar-type planet-hosting stars. In addition to 14 planet-hosting stars observed as part of the BCool magnetic snapshot survey, we obtained magnetic observations of a further 19 planet-hosting solar-type stars in order to see if the presence of close-in planets had an effect on the measured surface magnetic field (|B_l_|). Our results indicate that the magnetic activity of this sample is congruent with that of the overall BCool sample. The effects of the planetary systems on the magnetic activity of the parent star, if any, are too subtle to detect compared to the intrinsic dispersion and correlations with rotation, age and stellar activity proxies in our sample. Four of the 19 newly observed stars, two of which are subgiants, have unambiguously detected magnetic fields and are future targets for Zeeman-Doppler mapping.
- ID:
- ivo://CDS.VizieR/J/MNRAS/496/5423
- Title:
- 4 planet-hosting stars asteroseismic masses
- Short Name:
- J/MNRAS/496/5423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of planet occurrence as a function of stellar mass is important for a better understanding of planet formation. Estimating stellar mass, especially in the red giant regime, is difficult. In particular, stellar masses of a sample of evolved planet-hosting stars based on spectroscopy and grid-based modelling have been put to question over the past decade with claims they were overestimated. Although efforts have been made in the past to reconcile this dispute using asteroseismology, results were inconclusive. In an attempt to resolve this controversy, we study four more evolved planet-hosting stars in this paper using asteroseismology, and we revisit previous results to make an informed study of the whole ensemble in a self-consistent way. For the four new stars, we measure their masses by locating their characteristic oscillation frequency, numax, from their radial velocity time series observed by SONG. For two stars, we are also able to measure the large frequency separation, Delta nu, helped by extended SONG single-site and dual-site observations and new TESS observations. We establish the robustness of the numax-only-based results by determining the stellar mass from Delta nu, and from both Delta nu and numax. We then compare the seismic masses of the full ensemble of 16 stars with the spectroscopic masses from three different literature sources. We find an offset between the seismic and spectroscopic mass scales that is mass-dependent, suggesting that the previously claimed overestimation of spectroscopic masses only affects stars more massive than about 1.6M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/495/3961
- Title:
- Planet-hosting stars chemical compositions
- Short Name:
- J/MNRAS/495/3961
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a line-by-line differential analysis of a sample of 16 planet-hosting stars and 68 comparison stars using high-resolution, high signal-to-noise ratio spectra gathered using Keck. We obtained accurate stellar parameters and high-precision relative chemical abundances with average uncertainties in Teff, logg, [Fe/H], and [X/H] of 15K, 0.034cm/s^2^, 0.012dex, and 0.025dex, respectively. For each planet host, we identify a set of comparison stars and examine the abundance differences (corrected for Galactic chemical evolution effect) as a function of the dust condensation temperature, Tcond, of the individual elements. While we confirm that the Sun exhibits a negative trend between abundance and Tcond, we also confirm that the remaining planet hosts exhibit a variety of abundance-Tcond trends with no clear dependence upon age, metallicity, or Teff. The diversity in the chemical compositions of planet-hosting stars relative to their comparison stars could reflect the range of possible planet-induced effects present in these planet hosts, from the sequestration of rocky material (refractory poor) to the possible ingestion of planets (refractory rich). Other possible explanations include differences in the time-scale, efficiency and degree of planet formation, or inhomogeneous chemical evolution. Although we do not find an unambiguous chemical signature of planet formation among our sample, the high-precision chemical abundances of the host stars are essential for constraining the composition and structure of their exoplanets.
- ID:
- ivo://CDS.VizieR/J/AJ/153/136
- Title:
- Planets and their host stars with Gaia parallaxes
- Short Name:
- J/AJ/153/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present empirical measurements of the radii of 116 stars that host transiting planets. These radii are determined using only direct observables - the bolometric flux at Earth, the effective temperature, and the parallax provided by the Gaia first data release - and thus are virtually model independent, with extinction being the only free parameter. We also determine each star's mass using our newly determined radius and the stellar density, a virtually model independent quantity itself from previously published transit analyses. These stellar radii and masses are in turn used to redetermine the transiting-planet radii and masses, again using only direct observables. The median uncertainties on the stellar radii and masses are 8% and 30%, respectively, and the resulting uncertainties on the planet radii and masses are 9% and 22%, respectively. These accuracies are generally larger than previously published model-dependent precisions of 5% and 6% on the planet radii and masses, respectively, but the newly determined values are purely empirical. We additionally report radii for 242 stars hosting radial-velocity (non-transiting) planets, with a median achieved accuracy of ~2%. Using our empirical stellar masses we verify that the majority of putative "retired A stars" in the sample are indeed more massive than ~1.2 M_{sun}_. Most importantly, the bolometric fluxes and angular radii reported here for a total of 498 planet host stars-with median accuracies of 1.7% and 1.8%, respectively-serve as a fundamental data set to permit the re-determination of transiting-planet radii and masses with the Gaia second data release to ~3% and ~5% accuracy, better than currently published precisions, and determined in an entirely empirical fashion.
- ID:
- ivo://CDS.VizieR/J/AJ/159/194
- Title:
- Planets around main sequence stars in GALEX UV
- Short Name:
- J/AJ/159/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most (~82%) of the over 4000 confirmed exoplanets known today orbit very close to their host stars, within 0.5au. Planets at such small orbital distances can result in significant interactions with their host stars, which can induce increased activity levels in them. In this work, we have searched for statistical evidence for star-planet interactions in the ultraviolet (UV) using the largest sample of 1355 Galaxy Evolution Explorer (GALEX) detected host stars with confirmed exoplanets and making use of the improved host-star parameters from Gaia DR2. From our analysis, we do not find any significant correlation between the UV activity of the host stars and their planetary properties. We further compared the UV properties of planet host stars to that of chromospherically active stars from the RAdial Velocity Experiment (RAVE) survey. Our results indicate that the enhancement in chromospheric activity of host stars due to star-planet interactions may not be significant enough to reflect in their near and far V broadband flux.
- ID:
- ivo://CDS.VizieR/J/AJ/155/136
- Title:
- Planets orbiting bright stars in K2 campaigns 0-10
- Short Name:
- J/AJ/155/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since 2014, NASA's K2 mission has observed large portions of the ecliptic plane in search of transiting planets and has detected hundreds of planet candidates. With observations planned until at least early 2018, K2 will continue to identify more planet candidates. We present here 275 planet candidates observed during Campaigns 0-10 of the K2 mission that are orbiting stars brighter than 13 mag (in Kepler band) and for which we have obtained high-resolution spectra (R=44000). These candidates are analyzed using the vespa package in order to calculate their false-positive probabilities (FPP). We find that 149 candidates are validated with an FPP lower than 0.1%, 39 of which were previously only candidates and 56 of which were previously undetected. The processes of data reduction, candidate identification, and statistical validation are described, and the demographics of the candidates and newly validated planets are explored. We show tentative evidence of a gap in the planet radius distribution of our candidate sample. Comparing our sample to the Kepler candidate sample investigated by Fulton et al. (2017, J/AJ/154/109), we conclude that more planets are required to quantitatively confirm the gap with K2 candidates or validated planets. This work, in addition to increasing the population of validated K2 planets by nearly 50% and providing new targets for follow-up observations, will also serve as a framework for validating candidates from upcoming K2 campaigns and the Transiting Exoplanet Survey Satellite, expected to launch in 2018.
- ID:
- ivo://CDS.VizieR/J/AJ/160/221
- Title:
- Predicted planetary yields of gap transitional disks
- Short Name:
- J/AJ/160/221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a massive accreting gap planet model that ensures large gaps in transitional disks are kept dust free by the scattering action of three coplanar quasi-circular planets in a 1:2:4 mean motion resonance (MMR). This model uses the constraint of the observed gap size, and the dust-free nature of the gap, to determine within ~10% the possible orbits for three massive planets in an MMR. Calculated orbits are consistent with the observed orbits and H{alpha} emission (the brightest line to observe these planets) for LkCa15b, PDS70b, and PDS70c within observational errors. Moreover, the model suggests that the scarcity of detected H{alpha} planets is likely a selection effect of the current limitations of non-coronagraphic, low (<10%) Strehl, H{alpha} imaging with adaptive optics (AO) systems used in past H{alpha} surveys. We predict that as higher Strehl AO systems (with high- performance custom coronagraphs; like the 6.5m Magellan Telescope MagAO-X system) are utilized at H{alpha}, the number of detected gap planets will substantially increase by more than tenfold. For example, we show that >25{+/-}5 new H{alpha} "gap planets" are potentially discoverable by a survey of the best 19 transitional disks with MagAO-X. Detections of these accreting protoplanets will significantly improve our understanding of planet formation, planet growth and accretion, solar system architectures, and planet-disk interactions.
- ID:
- ivo://CDS.VizieR/J/AJ/161/179
- Title:
- Predicted positions of {beta}Pictoris b and c
- Short Name:
- J/AJ/161/179
- Date:
- 18 Jan 2022
- Publisher:
- CDS
- Description:
- We present a comprehensive orbital analysis to the exoplanets {beta}Pictoris b and c that resolves previously reported tensions between the dynamical and evolutionary mass constraints on {beta}Picb. We use the Markov Chain Monte Carlo orbit code orvara to fit 15years of radial velocities and relative astrometry (including recent GRAVITY measurements), absolute astrometry from Hipparcos and Gaia, and a single relative radial velocity measurement between {beta}Pic A and b. We measure model-independent masses of 9.3_-2.5_^+2.6^M_Jup_ for {beta}Picb and 8.3{+/-}1.0M_Jup_ for {beta}Picc. These masses are robust to modest changes to the input data selection. We find a well-constrained eccentricity of 0.119{+/-}0.008 for {beta}Picb, and an eccentricity of 0.21_-0.09_^+0.16^ for {beta}Picc, with the two orbital planes aligned to within ~0.5{deg}. Both planets' masses are within ~1{sigma} of the predictions of hot-start evolutionary models and exclude cold starts. We validate our approach on N-body synthetic data integrated using REBOUND. We show that orvara can account for three-body effects in the {beta}Pic system down to a level ~5 times smaller than the GRAVITY uncertainties. Systematics in the masses and orbital parameters from orvara's approximate treatment of multiplanet orbits are a factor of ~5 smaller than the uncertainties we derive here. Future GRAVITY observations will improve the constraints on {beta}Picc's mass and (especially) eccentricity, but improved constraints on the mass of {beta}Picb will likely require years of additional radial velocity monitoring and improved precision from future Gaia data releases.
- ID:
- ivo://CDS.VizieR/J/MNRAS/475/3090
- Title:
- Predicted properties for 468 RV planets
- Short Name:
- J/MNRAS/475/3090
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CHaracterizing ExOPlanets Satellite (CHEOPS) mission is planned for launch next year with a major objective being to search for transits of known radial velocity (RV) planets, particularly those orbiting bright stars. Since the RV method is only sensitive to planetary mass, the radii, transit depths and transit signal-to-noise values of each RV planet are, a priori, unknown. Using an empirically calibrated probabilistic mass-radius relation, forecaster, we address this by predicting a catalogue of homogeneous credible intervals for these three keys terms for 468 planets discovered via RVs. Of these, we find that the vast majority should be detectable with CHEOPS, including terrestrial bodies, if they have the correct geometric alignment. In particular, we predict that 22 mini-Neptunes and 82 Neptune-sized planets would be suitable for detection and that more than 80 per cent of these will have apparent magnitude of V<10, making them highly suitable for follow-up characterization work. Our work aims to assist the CHEOPS team in scheduling efforts and highlights the great value of quantifiable, statistically robust estimates for upcoming exoplanetary missions.
