- ID:
- ivo://CDS.VizieR/VI/151
- Title:
- Search for radio emission from giant exoplanets
- Short Name:
- VI/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The intensity of Jupiter's auroral radio emission quickly gave rise to the question whether a comparable coherent emission from the magnetosphere of an exoplanet could be detectable. An exoplanetary radio emission would have to be at least 1000 times more intense than Jupiter's emission to be detectable with current radio telescopes. Theoretical models suggest that, at least in certain cases, the radio emission of giant exoplanets may indeed reach the required intensity. At the same time, in order to generate such an emission, an exoplanet would have to have a sufficiently strong intrinsic planetary magnetic field. Extrasolar planets are indeed expected to have a planetary magnetic field, but to date, their magnetic field has never been detected. We will show that the most promising technique to observe exoplanetary magnetic fields is indeed to search for the planetary auroral radio emission. The detection of such an emission would thus constitute the first unambiguous detection of an exoplanetary magnetic field. We will review recent theoretical studies and discuss their results for the two main parameters, namely the maximum emission frequency and the intensity of the radio emission. The predicted values should allow the detection using modern low-frequency radio telescopes. We will present an ongoing observation program with the Low Frequency Array (LOFAR), which has the potential to detect exoplanetary radio emission.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/155/206
- Title:
- Search for rings around Kepler planet candidates
- Short Name:
- J/AJ/155/206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a systematic search for rings around 168 Kepler planet candidates with sufficient signal-to-noise ratios that are selected from all of the short-cadence data. We fit ringed and ringless models to their light curves and compare the fitting results to search for the signatures of planetary rings. First, we identify 29 tentative systems, for which the ringed models exhibit statistically significant improvement over the ringless models. The light curves of those systems are individually examined, but we are not able to identify any candidate that indicates evidence for rings. In turn, we find several mechanisms of false positives that would produce ringlike signals, and the null detection enables us to place upper limits on the size of the rings. Furthermore, assuming the tidal alignment between axes of the planetary rings and orbits, we conclude that the occurrence rate of rings larger than twice the planetary radius is less than 15%. Even though the majority of our targets are short-period planets, our null detection provides statistical and quantitative constraints on largely uncertain theoretical models of the origin, formation, and evolution of planetary rings.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A84
- Title:
- Search for UMa group companions
- Short Name:
- J/A+A/591/A84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a survey to detect low-mass companions of Ursa Major (UMa) group members, carried out in 2003-2006 with NACO at the ESO VLT. While many extra-solar planets and planetary candidates have been found in close orbits around stars by the radial velocity and the transit methods, direct detections at wider orbits are rare. The UMa group, a young nearby stellar association at an age of about 200-600Myr, has not yet been addressed as a whole although its members represent a very interesting sample to search for and characterize substellar companions by direct imaging. Our goal was to find or to provide detection limits on wide substellar companions around nearby UMa group members using high-resolution imaging. We searched for faint companions around 20 UMa group members within 30pc. The primaries were placed below a semi-transparent coronagraph, a rarely used mode of NACO, to increase the dynamic range of the images. In most cases, second epoch images of companion candidates were taken to check whether they share common proper motion with the primary.
- ID:
- ivo://CDS.VizieR/J/AJ/162/84
- Title:
- Searching for Small Circumbinary Planets. I. STANLEY
- Short Name:
- J/AJ/162/84
- Date:
- 16 Mar 2022 11:40:27
- Publisher:
- CDS
- Description:
- No circumbinary planets have been discovered smaller than 3R{Earth}, yet planets of this small size comprise over 75% of the discoveries around single stars. The observations do not prove the nonexistence of small circumbinary planets; rather, they are much harder to find than around single stars because their transit timing variations are much larger than the transit durations. We present Stanley, an automated algorithm to find small circumbinary planets. It employs custom methods to detrend eclipsing binary light curves and stack shallow transits of variable duration and interval using N-body integrations. Applied to the Kepler circumbinaries, we recover all known planets, including the three planets of Kepler-47, and constrain the absence of additional planets of similar or smaller size. We also show that we could have detected <3R{Earth} planets in half of the known systems. Our work will ultimately be applied to a broad sample of eclipsing binaries to (hopefully) produce new discoveries and derive a circumbinary size distribution that can be compared to that for single stars.
- ID:
- ivo://CDS.VizieR/J/AJ/152/181
- Title:
- SETI observations of exoplanets with the ATA
- Short Name:
- J/AJ/152/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report radio SETI observations on a large number of known exoplanets and other nearby star systems using the Allen Telescope Array (ATA). Observations were made over about 19000hr from 2009 May to 2015 December. This search focused on narrowband radio signals from a set totaling 9293 stars, including 2015 exoplanet stars and Kepler objects of interest and an additional 65 whose planets may be close to their habitable zones. The ATA observations were made using multiple synthesized beams and an anticoincidence filter to help identify terrestrial radio interference. Stars were observed over frequencies from 1 to 9GHz in multiple bands that avoid strong terrestrial communication frequencies. Data were processed in near-real time for narrowband (0.7-100Hz) continuous and pulsed signals with transmitter/receiver relative accelerations from -0.3 to 0.3m/s^2^. A total of 1.9x10^8^ unique signals requiring immediate follow-up were detected in observations covering more than 8x10^6^ star-MHz. We detected no persistent signals from extraterrestrial technology exceeding our frequency-dependent sensitivity threshold of 180-310x10^-26^W/m^2^.
1026. SHINE II
- ID:
- ivo://CDS.VizieR/J/A+A/651/A71
- Title:
- SHINE II
- Short Name:
- J/A+A/651/A71
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- In recent decades, direct imaging has confirmed the existence of substellar companions (exoplanets or brown dwarfs) on wide orbits (>10 au) around their host stars. In striving to understand their formation and evolution mechanisms, in 2015 we initiated the SPHERE infrared survey for exoplanets (SHINE), a systematic direct imaging survey of young, nearby stars that is targeted at exploring their demographics. We aim to detect and characterize the population of giant planets and brown dwarfs beyond the snow line around young, nearby stars. Combined with the survey completeness, our observations offer the opportunity to constrain the statistical properties (occurrence, mass and orbital distributions, dependency on the stellar mass) of these young giant planets. In this study, we present the observing and data analysis strategy, the ranking process of the detected candidates, and the survey performances for a subsample of 150 stars that are representative of the full SHINE sample. Observations were conducted in a homogeneous way between February 2015 and February 2017 with the dedicated ground-based VLT/SPHERE instrument equipped with the IFS integral field spectrograph and the IRDIS dual-band imager, covering a spectral range between 0.9 and 2.3m. We used coronographic, angular, and spectral differential imaging techniques to achieve the best detection performances for this study, down to the planetary mass regime. We processed, in a uniform manner, more than 300 SHINE observations and datasets to assess the survey typical sensitivity as a function of the host star and of the observing conditions. The median detection performance reached 5-contrasts of 13mag at 200mas and 14.2mag at 800mas with the IFS (YJ and YJH bands), and of 11.8mag at 200mas, 13.1mag at 800mas, and 15.8mag at 3as with IRDIS in H band, delivering one of the deepest sensitivity surveys thus far for young, nearby stars. A total of sixteen substellar companions were imaged in this first part of SHINE: seven brown dwarf companions and ten planetary-mass companions. These include two new discoveries, HIP 65426 b and HIP 64892 B, but not the planets around PDS70 that had not been originally selected for the SHINE core sample. A total of 1483 candidates were detected, mainly in the large field of view that characterizes IRDIS. The color-magnitude diagrams, low-resolution spectrum (when available with IFS), and follow-up observations enabled us to identify the nature (background contaminant or comoving companion) of about 86% of our subsample. The remaining cases are often connected to crowded-field follow-up observations that were missing. Finally, even though SHINE was not initially designed for disk searches, we imaged twelve circumstellar disks, including three new detections around the HIP 73145, HIP 86598, and HD106906 systems. Nowadays, direct imaging provides a unique opportunity to probe the outer part of exoplanetary systems beyond 10au to explore planetary architectures, as highlighted by the discoveries of: one new exoplanet, one new brown dwarf companion, and three new debris disks during this early phase of SHINE. It also offers the opportunity to explore and revisit the physical and orbital properties of these young, giant planets and brown dwarf companions (relative position, photometry, and low-resolution spectrum in near-infrared, predicted masses, and contrast in order to search for additional companions). Finally, these results highlight the importance of finalizing the SHINE systematic observation of about 500 young, nearby stars for a full exploration of their outer part to explore the demographics of young giant planets beyond 10au and to identify the most interesting systems for the next generation of high-contrast imagers on very large and extremely large telescopes.
- ID:
- ivo://CDS.VizieR/J/PAZh/41/896
- Title:
- Short- and long-term pm of close dwarfs
- Short Name:
- J/PAZh/41/896
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Motions of 1308 stars with large proper motions ({mu}>300mas/yr) up to 17 mag were investigated using the results of observations conducted with Pulkovo Normal Astrograph and images taken from data bases of sky surveys (DSS, SDSS DR12, WISE). Basic idea of search of double stars with this material is a comparison between long-term proper motion (POSS2-POSS1, epoch difference is about 50yr) and short-term proper motion (2MASS, SDSS, WISE, Pulkovo, epoch difference is about 10yr). Star is classified as delta-mu-binary candidate in the case of statistically significant difference of short-term and long-term proper motions. This condition is realised for 121 stars of our target list. Additional evidence of duplicity was obtained with comparison of our proper motions with data of several parallax determination programs. Analysis of accurate SDSS photometric values of our stars allows us to conclude that four stars (J0656+3827, J0838+3940, J1229+5332, J2330+4639) are probably binary systems which consist of wite dwarf + M-dwarf.
- ID:
- ivo://CDS.VizieR/J/ApJS/239/2
- Title:
- Simulated exoplanets from TESS list of targets
- Short Name:
- J/ApJS/239/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transiting Exoplanet Survey Satellite (TESS) has a goal of detecting small planets orbiting stars bright enough for mass determination via ground-based radial velocity observations. Here, we present estimates of how many exoplanets the TESS mission will detect, the physical properties of the detected planets, and the properties of the stars that those planets orbit. This work uses stars drawn from the TESS Input Catalog (TIC) Candidate Target List and revises yields from prior studies that were based on Galactic models. We modeled the TESS observing strategy to select approximately 200000 stars at 2-minute cadence, while the remaining stars are observed at 30-minute cadence in full-frame image data. We placed zero or more planets in orbit around each star, with physical properties following measured exoplanet occurrence rates, and used the TESS noise model to predict the derived properties of the detected exoplanets. In the TESS 2-minute cadence mode we estimate that TESS will find 1250+/-70 exoplanets (90% confidence), including 250 smaller than 2R_{Earth}_. Furthermore, we predict that an additional 3100 planets will be found in full-frame image data orbiting bright dwarf stars and more than 10000 around fainter stars. We predict that TESS will find 500 planets orbiting M dwarfs, but the majority of planets will orbit stars larger than the Sun. Our simulated sample of planets contains hundreds of small planets amenable to radial velocity follow-up, potentially more than tripling the number of planets smaller than 4R_{Earth}_ with mass measurements. This sample of simulated planets is available for use in planning follow-up observations and analyses.
- ID:
- ivo://CDS.VizieR/J/MNRAS/486/5867
- Title:
- Simulated Transit depths of 12 Hot Jupiters
- Short Name:
- J/MNRAS/486/5867
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study of synergies between space telescopes (HST, CHEOPS, TESS, JWST, PLATO) in the photometric characterization of the atmospheres of Hot Jupiters. We analyze a set of planetary systems hosting a Hot Jupiter for which an atmospheric template is available in literature. For each system, we simulate the transit light curves observed by different instruments, convolving the incoming spectrum with the corresponding instrumental throughput. For each instrument, we thus measure the expected transit depth and estimate the associated uncertainty. Finally, we compare the transit depths as seen by the selected instruments and we quantify the effect of the planetary atmosphere on multi-band transit photometry.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/1044
- Title:
- Simulation data for 50 planetary model systems
- Short Name:
- J/MNRAS/448/1044
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the long-term evolution of compact systems of terrestrial planets, using a set of simulations that match the statistical properties of the observed exoplanet distribution. The evolution is driven by tidal dissipation in the planetary interiors, but the systems evolve as a whole due to secular gravitational interactions. We find that, for Earth-like dissipation levels, planetary orbits can be circularized out to periods ~100 d, an order of magnitude larger than is possible for single planets. The resulting distribution of eccentricities is a qualitative match to that inferred from transit timing variations, with a minority of non-zero eccentricities maintained by particular secular configurations. The coupling of the tidal and secular processes enhance the inward migration of the innermost planets in these systems, and can drive them to short orbital periods. Resonant interactions of both the mean motion and secular variety are observed, although the interactions are not strong enough to drive systemic instability in most cases. However, we demonstrate that these systems can easily be driven unstable if coupled to giant planets on longer period orbits.
