- ID:
- ivo://CDS.VizieR/J/A+A/619/A97
- Title:
- CoRoT transit catalogue
- Short Name:
- J/A+A/619/A97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CoRoT space mission observed 163665 stars over 26 stellar fields in the faint star channel. The exoplanet teams detected a total of 4123 transit-like features in the 177454 light curves. We present the complete re-analysis of all these detections carried out with the same softwares so that to ensure their homogeneous analysis. Although the vetting process involves some human evaluation, it also involves a simple binary flag system over basic tests: detection significance, presence of a secondary, difference between odd and even depths, colour dependence, V-shape transit, and duration of the transit. We also gathered the information from the large accompanying ground-based programme carried out on the planet candidates and checked how useful the flag system could have been at the vetting stage of the candidates. From the initial list of transit-like features, we identified and separated 824 false alarms of various kind, 2269 eclipsing binaries among which 616 are contact binaries and 1653 are detached ones, 37 planets and brown dwarfs, and 557 planet candidates. We provide the catalogue of all these transit-like features, including false alarms. For the planet candidates, the catalogue gives not only their transit parameters but also the products of their light curve modelling: reduced radius, reduced semi-major axis, and impact parameter, together with a summary of the outcome of follow-up observations when carried out and their current status. For the detached eclipsing binaries, the catalogue provides, in addition to their transit parameters, a simple visual classification. Among the planet candidates whose nature remains unresolved, we estimate that eight (within an error of three) planets are still to be identified. After correcting for geometric and sensitivity biases, we derived planet and brown dwarf occurrences and confirm disagreements with Kepler estimates, as previously reported by other authors from the analysis of the first runs: small-size planets with orbital period less than ten days are underabundant by a factor of three in the CoRoT fields whereas giant planets are overabundant by a factor of two. These preliminary results would however deserve further investigations using the recently released CoRoT light curves that are corrected of the various instrumental effects and a homogeneous analysis of the stellar populations observed by the two missions.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/154/142
- Title:
- Corrected photometry for GJ 1132 for all eclipses
- Short Name:
- J/AJ/154/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for additional bodies in the GJ 1132 system through two methods: photometric transits and transit timing variations of GJ 1132b. We collected 21 transit observations of GJ 1132b with the MEarth-South array. We obtained 100 near-continuous hours of observations with the Spitzer Space Telescope, including two transits of GJ 1132b and spanning 60% of the orbital phase of the maximum (6.9-day) period at which bodies coplanar with GJ 1132b would transit. We exclude transits of additional Mars-sized bodies, such as a second planet or a moon, with a confidence of 99.7%. We find that the planet-to-star radius ratio inferred from the MEarth and Spitzer light curves are discrepant at the 3.7{sigma} level, which we ascribe to the effects of starspots and faculae. When we combine the mass estimate of the star (obtained from its parallax and apparent K_s_ band magnitude) with the stellar density inferred from our high-cadence Spitzer light curve (assuming zero eccentricity), we measure the stellar radius of GJ 1132 to be 0.2105_-0.0085_^+0.0102^ R_{sun}_, and we refine the radius measurement of GJ 1132b to 1.130+/-0.056 R_{Earth}_. Combined with HARPS RV measurements, we determine the density of GJ 1132b to be 6.2+/-2.0 g/cm^3^. We refine the ephemeris of the system (improving the period determination by an order of magnitude) and find no evidence for transit timing variations, which would be expected if there was a second planet near an orbital resonance with GJ 1132b.
- ID:
- ivo://CDS.VizieR/J/AJ/159/41
- Title:
- Data for ~550 exoplanets using a neural network
- Short Name:
- J/AJ/159/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- While thousands of exoplanets have been confirmed, the known properties about individual discoveries remain sparse and depend on detection technique. To utilize more than a small section of the exoplanet data set, tools need to be developed to estimate missing values based on the known measurements. Here, we demonstrate the use of a neural network that models the density of planets in a space of six properties that is then used to impute a probability distribution for missing values. Our results focus on planetary mass, which neither the radial velocity nor transit techniques for planet identification can provide alone. The neural network can impute mass across the four orders of magnitude in the exoplanet archive, and return a distribution of masses for each planet that can inform us about trends in the underlying data set. The average error on this mass estimate from a radial velocity detection is a factor of 1.5 of the observed value, and 2.7 for a transit observation. The mass of Proxima Centauri b found by this method is 1.6_-0.36_^+0.46^M{Earth}, where the upper and lower bounds are derived from the root mean square deviation from the log mass probability distribution. The network can similarly impute the other potentially missing properties, and we use this to predict planet radius for radial velocity measurements, with an average error of a factor 1.4 of the observed value. The ability of neural networks to search for patterns in multidimensional data means that such techniques have the potential to greatly expand the use of the exoplanet catalog.
- ID:
- ivo://CDS.VizieR/J/AJ/157/124
- Title:
- DAVE. I. Benchmarking K2 vetting tools
- Short Name:
- J/AJ/157/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have adapted the algorithmic tools developed during the Kepler mission to vet the quality of transit-like signals for use on the K2 mission data. Using the four sets of publicly available light curves at MAST, we produced a uniformly vetted catalog of 772 transiting planet candidates from K2 as listed at the NASA Exoplanet Archive in the K2 Table of Candidates. Our analysis marks 676 of these as planet candidates and 96 as false positives. All confirmed planets pass our vetting tests. Sixty of our false positives are new identifications, effectively doubling the overall number of astrophysical signals mimicking planetary transits in K2 data. Most of the targets listed as false positives in our catalog show either prominent secondary eclipses, transit depths suggesting a stellar companion instead of a planet, or significant photocenter shifts during transit. We packaged our tools into the open-source, automated vetting pipeline Discovery and Vetting of Exoplanets (DAVE), designed to streamline follow-up efforts by reducing the time and resources wasted observing targets that are likely false positives. DAVE will also be a valuable tool for analyzing planet candidates from NASA's TESS mission, where several guest-investigator programs will provide independent light-curve sets - and likely many more from the community. We are currently testing DAVE on recently released TESS planet candidates and will present our results in a follow-up paper.
- ID:
- ivo://CDS.VizieR/J/AJ/160/84
- Title:
- Depth-of-search & completness for 213 exoplanets
- Short Name:
- J/AJ/160/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Identifying which systems are more likely to host an imageable planet can play an important role in the construction of an optimized target list for future direct imaging missions, such as the planned Coronagraph Instrument (CGI) technology demonstration for the Nancy Grace Roman Space Telescope. For single-planet systems, the presence of an already detected exoplanet can severely restrict the target's stable region and should therefore be considered when searching for unknown companions. To do so, we first analyze the performance and robustness of several two-planet stability criteria by comparing them with long-term numerical simulations. We then derive the necessary formulation for the computation of (a, R) analytic stability maps, which can be used in conjunction with depth-of-search grids in order to define the stable-imageable region of a system. The dynamically stable completeness (i.e., the expected number of imageable and stable planets) can then be calculated via convolution with the selected occurrence grid, obtaining a metric that can be directly compared for imaging prioritization. Applying this procedure to all the currently known single-planet systems within a distance of 50pc, we construct a ranked target list based on the CGI's predicted performance and SAG13 occurrence rates. Finally, we evaluate the importance of considering the radial velocity data from past Doppler surveys in order to rule out entire regions of our parameter space where, if a planet existed, it would have certainly been detected by previous RV observations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/1763
- Title:
- Detectability of radio emission from exoplanets
- Short Name:
- J/MNRAS/478/1763
- Date:
- 19 Jan 2022 00:23:37
- Publisher:
- CDS
- Description:
- Like the magnetized planets in our Solar system, magnetized exoplanets should emit strongly at radio wavelengths. Radio emission directly traces the planetary magnetic fields and radio detections can place constraints on the physical parameters of these features. Large comparative studies of predicted radio emission characteristics for the known population of exoplanets help to identify what physical parameters could be the key for producing bright, observable radio emission. Since the last comparative study, many thousands of exoplanets have been discovered. We report new estimates for the radio flux densities and maximum emission frequencies for the current population of known exoplanets orbiting pre-main-sequence and main-sequence stars with spectral types F-M. The set of exoplanets predicted to produce observable radio emission are Hot Jupiters orbiting young stars. The youth of these systems predicts strong stellar magnetic fields and/or dense winds, which are the key for producing bright, observable radio emission. We use a new all-sky circular polarization Murchison Widefield Array survey to place sensitive limits on 200MHz emission from exoplanets, with 3{sigma} values ranging from 4.0 to 45.0mJy. Using a targeted Giant Metrewave Radio Telescope observing campaign, we also report a 3{sigma} upper limit of 4.5mJy on the radio emission from V830 Tau b, the first Hot Jupiter to be discovered orbiting a pre-main-sequence star. Our limit is the first to be reported for the low-frequency radio emission from this source.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A7
- Title:
- Determining true mass of RV exoplanets with Gaia
- Short Name:
- J/A+A/645/A7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mass is one of the most important parameters for determining the true nature of an astronomical object. Yet, many published exoplan- ets lack a measurement of their true mass, in particular those detected as a result of radial-velocity (RV) variations of their host star. For those examples, only the minimum mass, or msini, is known, owing to the insensitivity of RVs to the inclination of the detected orbit compared to the plane of the sky. The mass that is given in databases is generally that of an assumed edge-on system (~90{deg}), but many other inclinations are possible, even extreme values closer to 0{deg} (face-on). In such a case, the mass of the published object could be strongly underestimated by up to two orders of magnitude. In the present study, we use GASTON, a recently developed tool taking advantage of the voluminous Gaia astrometric database to constrain the inclination and true mass of several hundreds of published exoplanet candidates. We find 9 exoplanet candidates in the stellar or brown dwarf (BD) domain, among which 6 were never characterized. We show that 30 Ari B b, HD 141937 b, HD 148427 b, HD 6718 b, HIP 65891 b, and HD 16760 b have masses larger than 13.5 M_J_ at 3{sigma}. We also confirm the planetary nature of 27 exoplanets, including HD 10180 c, d and g. Studying the orbital periods, eccentricities, and host-star metallicities in the BD domain, we found distributions with respect to true masses consistent with other publications. The distribution of orbital periods shows of a void of BD detections below ~100d, while eccentricity and metallicity distributions agree with a transition between BDs similar to planets and BDs similar to stars in the range 40-50M_J_.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A35
- Title:
- Differential photometry of GJ1214
- Short Name:
- J/A+A/614/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To investigate the star spots of the M dwarf GJ 1214, we conducted a multi-color photometric monitoring from 2012 to 2016. We measured the rotation period of the host star, measured an increase in variability amplitude, determined the permanent spot filling factor, the spot temperature contrast and persistent longitudes. We determined the effect of the star spots on the planetary transmission spectrum.
- ID:
- ivo://CDS.VizieR/J/AJ/153/211
- Title:
- Differential photometry of the F-subgiant HAT-P-67
- Short Name:
- J/AJ/153/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HAT-P-67b, which is a hot-Saturn transiting a rapidly rotating F-subgiant. HAT-P-67b has a radius of R_p_=2.085_-0.071_^+0.096^ R_J_, and orbites a M_*_=1.642_-0.072_^+0.155^ M_{sun}_, R_*_=2.546_-0.084_^+0.099^ R_{sun}_ host star in a ~4.81 day period orbit. We place an upper limit on the mass of the planet via radial velocity measurements to be M_p_<0.59 M_J_, and a lower limit of >0.056 M_J_ by limitations on Roche lobe overflow. Despite being a subgiant, the host star still exhibits relatively rapid rotation, with a projected rotational velocity of vsini_*_=35.8+/-1.1 km/s, which makes it difficult to precisely determine the mass of the planet using radial velocities. We validated HAT-P-67b via two Doppler tomographic detections of the planetary transit, which eliminate potential eclipsing binary blend scenarios. The Doppler tomographic observations also confirm that HAT-P-67b has an orbit that is aligned to within 12{deg}, in projection, with the spin of its host star. HAT-P-67b receives strong UV irradiation and is among one of the lowest density planets known, which makes it a good candidate for future UV transit observations in the search for an extended hydrogen exosphere.
- ID:
- ivo://CDS.VizieR/J/AJ/157/31
- Title:
- Differential photometry & radial velocities of HATS-70
- Short Name:
- J/AJ/157/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HATS-70b, a transiting brown dwarf at the deuterium burning limit. HATS-70b has a mass of M_p_=12.9_-1.6_^+1.8^ M_Jup_ and a radius of R_p_=1.384_-0.074_^+0.079^ R_Jup_, residing in a close-in orbit with a period of 1.89 days. The host star is a M_*_=1.78+/-0.12 M_{sun}_ A star rotating at vsinI_*_=40.61_-0.35_^+0.32^ km/s, enabling us to characterize the spectroscopic transit of the brown dwarf via Doppler tomography. We find that HATS-70b, like other massive planets and brown dwarfs previously sampled, orbits in a low projected-obliquity orbit with {lambda}=8.9_-4.5_^+5.6o^. The low obliquities of these systems is surprising given all brown dwarf and massive planets with obliquities measured orbit stars hotter than the Kraft break. This trend is tentatively inconsistent with dynamically chaotic migration for systems with massive companions, though the stronger tidal influence of these companions makes it difficult to draw conclusions on the primordial obliquity distribution of this population. We also introduce a modeling scheme for planets around rapidly rotating stars, accounting for the influence of gravity darkening on the derived stellar and planetary parameters.
