- ID:
- ivo://CDS.VizieR/J/MNRAS/465/3693
- Title:
- 7 WASP-South transiting exoplanets
- Short Name:
- J/MNRAS/465/3693
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe seven exoplanets transiting stars of brightness V=10.1-12.4. WASP-130b is a 'warm Jupiter' having an orbital period of 11.6d around a metal-rich G6 star. Its mass and radius (1.23+/-0.04M_Jup_ and 0.89+/-0.03R_Jup_) support the trend that warm Jupiters have smaller radii than hot Jupiters. WASP-131b is a bloated Saturn-mass planet (0.27M_Jup_ and 1.22R_Jup_). Its large scaleheight and bright (V=10.1) host star make it a good target for atmospheric characterization. WASP-132b (0.41M_Jup_ and 0.87R_Jup_) is among the least irradiated and coolest of WASP planets, having a 7.1-d orbit around a K4 star. WASP-139b is a 'super-Neptune' akin to HATS-7b and HATS-8b, being the lowest mass planet yet found by WASP (0.12M_Jup_ and 0.80R_Jup_). The metal-rich K0 host star appears to be anomalously dense, akin to HAT-P-11. WASP-140b is a 2.4M_Jup_ planet in an eccentric (e=0.047+/-0.004) 2.2d orbit. The planet's radius is large (1.4R_Jup_), but uncertain owing to the grazing transit (b=0.93). The 10.4d rotation period of the K0 host star suggests a young age, and the time-scale for tidal circularization is likely to be the lowest of all known eccentric hot Jupiters. WASP-141b (2.7M_Jup_, 1.2R_Jup_ and P=3.3d) and WASP-142b (0.84M_Jup_, 1.53R_Jup_ and P=2.1d) are typical hot Jupiters orbiting metal-rich F stars. We show that the period distribution within the hot-Jupiter bulge does not depend on the metallicity of the host star.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/457/4205
- Title:
- WASP-22, WASP-41, WASP-42, WASP-55
- Short Name:
- J/MNRAS/457/4205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 13 high-precision and four additional light curves of four bright southern-hemisphere transiting planetary systems: WASP-22, WASP-41, WASP-42 and WASP-55. In the cases of WASP-42 and WASP-55, these are the first follow-up observations since their discovery papers. We present refined measurements of the physical properties and orbital ephemerides of all four systems. No indications of transit timing variations were seen. All four planets have radii inflated above those expected from theoretical models of gas-giant planets; WASP-55 b is the most discrepant with a mass of 0.63M_Jup_ and a radius of 1.34R_Jup_. WASP-41 shows brightness anomalies during transit due to the planet occulting spots on the stellar surface. Two anomalies observed 3.1d apart are very likely due to the same spot. We measure its change in position and determine a rotation period for the host star of 18.6+/-1.5d, in good agreement with a published measurement from spot-induced brightness modulation, and a sky-projected orbital obliquity of {lambda}=6+/-11{deg}. We conclude with a compilation of obliquity measurements from spot-tracking analyses and a discussion of this technique in the study of the orbital configurations of hot Jupiters.
- ID:
- ivo://CDS.VizieR/J/other/Nat/576.61
- Title:
- WDJ0914+1914 X-Shooter spectrum
- Short Name:
- J/other/Nat/576.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detection of a dust disk around the white dwarf star G29-38 and transits from debris orbiting the white dwarf WD 1145+017 confirmed that the photospheric trace metals found in many white dwarfs arise from the accretion of tidally disrupted planetesimals. The composition of these planetesimals is similar to that of rocky bodies in the inner Solar System. Gravitational scattering of planetesimals towards the white dwarf requires the presence of more massive bodies, yet no planet has so far been detected at a white dwarf. Here we report optical spectroscopy of a hot (about 27750 kelvin) white dwarf, WD J091405.30+191412.25, that is accreting from a circumstellar gaseous disk composed of hydrogen, oxygen and sulfur at a rate of about 3.3x10<SUP>9</SUP> grams per second. The composition of this disk is unlike all other known planetary debris around white dwarfs, but resembles predictions for the makeup of deeper atmospheric layers of icy giant planets, with H<SUB>2</SUB>O and H<SUB>2</SUB>S being major constituents. A giant planet orbiting a hot white dwarf with a semi-major axis of around 15 solar radii will undergo substantial evaporation with expected mass loss rates comparable to the accretion rate that we observe onto the white dwarf. The orbit of the planet is most probably the result of gravitational interactions, indicating the presence of additional planets in the system. We infer an occurrence rate of approximately 1 in 10000 for spectroscopically detectable giant planets in close orbits around white dwarfs.
- ID:
- ivo://CDS.VizieR/J/AJ/156/137
- Title:
- Wide-orbit Exoplanet search with IR Direct imaging
- Short Name:
- J/AJ/156/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results from the Wide-orbit Exoplanet search with InfraRed Direct imaging, or WEIRD, a survey designed to search for Jupiter-like companions on very wide orbits (1000-5000 au) around young stars (<120 Myr) that are known members of moving groups in the solar neighborhood (<70 pc). Companions that share the same age, distance, and metallicity as their host while being on large enough orbits to be studied as "isolated" objects make prime targets for spectroscopic observations, and they are valuable benchmark objects for exoplanet atmosphere models. The search strategy is based on deep imaging in multiple bands across the near-infrared domain. For all 177 objects of our sample, z'_ab_, J, [3.6], and [4.5] images were obtained with CFHT/MegaCam, GEMINI/GMOS, CFHT/WIRCam, GEMINI/Flamingos-2, and Spitzer/IRAC. Using this set of four images per target, we searched for sources with red z'_ab_ and [3.6]-[4.5] colors, typically reaching good completeness down to 2 M_Jup_ companions, while going down to 1 M_Jup_ for some targets, at separations of 1000-5000 au. The search yielded four candidate companions with the expected colors, but they were all rejected through follow-up proper motion observations. Our results constrain the occurrence of 1-13 M_Jup_ planetary-mass companions on orbits with a semimajor axis between 1000 and 5000 au at less than 0.03, with a 95% confidence level.
- ID:
- ivo://CDS.VizieR/J/AJ/160/81
- Title:
- 20 years of Beta CVn HIRES/APF radial velocities
- Short Name:
- J/AJ/160/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Uncovering the occurrence rate of terrestrial planets within the habitable zone (HZ) of their host stars has been a particular focus of exoplanetary science in recent years. The statistics of these occurrence rates have largely been derived from transiting planet discoveries, and have uncovered numerous HZ planets in compact systems around M-dwarf host stars. Here we explore the width of the HZ as a function of spectral type, and the dynamical constraints on the number of stable orbits within the HZ for a given star. We show that, although the Hill radius for a given planetary mass increases with larger semimajor axis, the width of the HZ for earlier-type stars allows for more terrestrial planets in the HZ than late-type stars. In general, dynamical constraints allow ~6 HZ Earth-mass planets for stellar masses >~0.7M{sun}, depending on the presence of farther out giant planets. As an example, we consider the case of Beta CVn, a nearby bright solar-type star. We present 20yr of radial velocities (RV) from the Keck/High Resolution Echelle Spectrometer (HIRES) and Automated Planet Finder (APF) instruments and conduct an injection-recovery analysis of planetary signatures in the data. Our analysis of these RV data rule out planets more massive than Saturn within 10 au of the star. These system properties are used to calculate the potential dynamical packing of terrestrial planets in the HZ and show that such nearby stellar targets could be particularly lucrative for HZ planet detection by direct imaging exoplanet missions.
- ID:
- ivo://CDS.VizieR/J/AJ/161/157
- Title:
- 10 years radial-velocity monitoring of Vega with TRES
- Short Name:
- J/AJ/161/157
- Date:
- 18 Jan 2022
- Publisher:
- CDS
- Description:
- We present an analysis of 1524 spectra of Vega spanning 10yr, in which we search for periodic radial-velocity variations. A signal with a periodicity of 0.676day and a semi-amplitude of ~10m/s is consistent with the rotation period measured over much shorter time spans by previous spectroscopic and spectropolarimetric studies, confirming the presence of surface features on this A0 star. The activity signal appears to evolve on long timescales, which may indicate the presence of failed fossil magnetic fields on Vega. TESS data reveal Vega's photometric rotational modulation for the first time, with a total amplitude of only 10ppm. A comparison of the spectroscopic and photometric amplitudes suggests that the surface features may be dominated by bright plages rather than dark spots. For the shortest orbital periods, transit and radial-velocity injection recovery tests exclude the presence of transiting planets larger than 2R{Earth} and most non- transiting giant planets. At long periods, we combine our radial velocities with direct imaging from the literature to produce detection limits for Vegan planets and brown dwarfs out to distances of 15au. Finally, we detect a candidate radial-velocity signal with a period of 2.43days and a semi-amplitude of 6m/s. If caused by an orbiting companion, its minimum mass would be ~20M{Earth}; because of Vega's pole-on orientation, this would correspond to a Jovian planet if the orbit is aligned with the stellar spin. We discuss the prospects for confirmation of this candidate planet.
- ID:
- ivo://CDS.VizieR/J/A+A/636/A119
- Title:
- YZ Ceti CARMENES and HARPS radial velocity curve
- Short Name:
- J/A+A/636/A119
- Date:
- 25 Oct 2021 00:44:17
- Publisher:
- CDS
- Description:
- The nearby ultra-compact multiplanetary system YZ Ceti consists of at least three planets, and a fourth tentative signal. The orbital period of each planet is the subject of discussion in the literature due to strong aliasing in the radial velocity data. The stellar activity of this M dwarf also hampers significantly the derivation of the planetary parameters. With an additional 229 radial velocity measurements obtained since the discovery publication, we reanalyze the YZ Ceti system and resolve the alias issues. We use model comparison in the framework of Bayesian statistics and periodogram simulations based on a method by Dawson and Fabrycky to resolve the aliases. We discuss additional signals in the RV data, and derive the planetary parameters by simultaneously modeling the stellar activity with a Gaussian process regression model. To constrain the planetary parameters further we apply a stability analysis on our ensemble of Keplerian fits. We find no evidence for a fourth possible companion. We resolve the aliases: the three planets orbit the star with periods of 2.02d, 3.06d, and 4.66d. We also investigate an effect of the stellar rotational signal on the derivation of the planetary parameters, in particular the eccentricity of the innermost planet. Using photometry we determine the stellar rotational period to be close to 68d and we also detect this signal in the residuals of a three-planet fit to the RV data and the spectral activity indicators. From our stability analysis we derive a lower limit on the inclination of the system with the assumption of coplanar orbits which is i_min_=0.9deg. From the absence of a transit event with TESS, we derive an upper limit of the inclination of i_max_=87.43deg. YZ Ceti is a prime example of a system where strong aliasing hindered the determination of the orbital periods of exoplanets. Additionally, stellar activity influences the derivation of planetary parameters and modeling them correctly is important for the reliable estimation of the orbital parameters in this specific compact system. Stability considerations then allow additional constraints to be placed on the planetary parameters.
