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22341. Transiting exoplanet TrES-3b CCD UBVR photometry
ID:
ivo://CDS.VizieR/J/MNRAS/428/678
Title:
Transiting exoplanet TrES-3b CCD UBVR photometry
Short Name:
J/MNRAS/428/678
Date:
21 Oct 2021
Publisher:
CDS
Description:
We observed nine primary transits of the hot Jpiter TrES-3b in several optical and near-UV photometric bands from 2009 June to 2012 April in an attempt to detect its magnetic field. Vidotto, Jardine and Helling suggest that the magnetic field of TrES-3b can be constrained if its near-UV light curve shows an early ingress compared to its optical light curve, while its egress remains unaffected. Predicted magnetic field strengths of Jupiter-like planets should range between 8G and 30G. Using these magnetic field values and an assumed B* of 100G, the Vidotto et al. method predicts a timing difference of 5-11min. We did not detect an early ingress in our three nights of near-UV observations, despite an average cadence of 68 s and an average photometric precision of 3.7mmag. However, we determined an upper limit of TrES-3b's magnetic field strength to range between 0.013 and 1.3G (for a 1-100G magnetic field strength range for the host star, TrES-3) using a timing difference of 138s derived from the Nyquist-Shannon sampling theorem. To verify our results of an abnormally small magnetic field strength for TrES-3b and to further constrain the techniques of Vidotto et al., we propose future observations of TrES-3b with other platforms capable of achieving a shorter near-UV cadence. We also present a refinement of the physical parameters of TrES-3b, an updated ephemeris and its first published near-UV light curve. We find that the near-UV planetary radius of Rp=1.386+0.248-0.144RJup is consistent with the planet's optical radius.
22342. Transiting extrasolar planet HD 209458b
ID:
ivo://CDS.VizieR/J/ApJ/649/1043
Title:
Transiting extrasolar planet HD 209458b
Short Name:
J/ApJ/649/1043
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have measured the infrared transit of the extrasolar planet HD 209458b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24um array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10s integrations) of the planetary system, recorded before, during, and after transit. We performed optimal photometry on the images and used the local zodiacal light as a short-term flux reference. At this long wavelength, the transit curve has a simple boxlike shape, allowing robust solutions for the stellar and planetary radii independent of stellar limb darkening, which is negligible at 24um. We derive a stellar radius of R*=(1.06+/-0.07)R_{sun}_, a planetary radius of Rp=(1.26+/-0.08)R_J_, and a stellar mass of 1.17M_{sun}_. Within the errors, our results agree with the measurements at visible wavelengths. The 24um radius of the planet therefore does not differ significantly compared to the visible result. We point out the potential for deriving extrasolar transiting planet radii to high accuracy using transit photometry at slightly shorter IR wavelengths where greater photometric precision is possible.
22343. Transiting extrasolar planet WASP-33b
ID:
ivo://CDS.VizieR/J/A+A/553/A44
Title:
Transiting extrasolar planet WASP-33b
Short Name:
J/A+A/553/A44
Date:
21 Oct 2021
Publisher:
CDS
Description:
HD 15082 (WASP-33) is the hottest and fastest rotating star known to harbor a transiting extrasolar planet (WASP-33b) The lack of high precision radial velocity (RV) data stresses the need for precise light curve analysis and gathering further RV data. By using available photometric and RV data, we perform a blend analysis, compute more accurate system parameters, confine the planetary mass and attempt to cast light on the observed transit anomalies. We combine the original HATNet observations and various followup data to jointly analyze the signal content and extract the transit component and use our RV data to aid the global parameter determination. The blend analysis of the combination of multicolor light curves yields the first independent confirmation of the planetary nature of WASP-33b. We clearly identify three frequency components in the 15-21c/d regime with amplitudes 5-7mmag. These frequencies correspond to the delta Scuti-type pulsation of the host star. None of these pulsation frequencies or their low-order linear combinations are in close resonance with the orbital frequency. We show that these pulsation components explain some but not all of the observed transit anomalies. The grand-averaged transit light curve shows that there is a ~1.5mmag brightening shortly after the planet passes the mid-transit phase. Although the duration and amplitude of this brightening varies, it is visible even through the direct inspections of the individual transit events (some 40-60% of the followup light curves show this phenomenon). We suggest that the most likely explanation of this feature is the presence of a well-populated spot belt which is highly inclined to the orbital plane. This geometry is consistent with the inference from the spectroscopic anomalies. Finally, we constrain the planetary mass to M_p_=3.27+/-0.73M_J_ by using our RV data collected by the TRES spectrograph.
22344. 4 transiting F-M binary systems
ID:
ivo://CDS.VizieR/J/MNRAS/437/2831
Title:
4 transiting F-M binary systems
Short Name:
J/MNRAS/437/2831
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of four transiting F-M binary systems with companions between 0.1 and 0.2M_{sun}_ in mass by the HATSouth survey. These systems have been characterized via a global analysis of the HATSouth discovery data, combined with high-resolution radial velocities and accurate transit photometry observations. We determined the masses and radii of the component stars using a combination of two methods: isochrone fitting of spectroscopic primary star parameters and equating spectroscopic primary star rotation velocity with spin-orbit synchronization. These new very low mass companions are HATS550-016B (0.110_-0.006_^+0.005^M_{sun}_, 0.147_-0.004_^+0.003^R_{sun}_), HATS551-019B (0.17_-0.01_^+0.01^M_sun}_, 0.18_-0.01_^+0.01^R_{sun}_), HATS551-021B (0.132_-0.005_^+0.014^M_sun}_, 0.154_-0.008_^+0.006^R_{sun}_) and HATS553-001B (0.20_-0.02_^+0.01^M_sun}_, 0.22_-0.01_^+0.01^R_{sun}_). We examine our sample in the context of the radius anomaly for fully convective low-mass stars. Combining our sample with the 13 other well-studied very low mass stars, we find a tentative 5 percent systematic deviation between the measured radii and theoretical isochrone models.
22345. Transiting planetary system WASP-17
ID:
ivo://CDS.VizieR/J/MNRAS/426/1338
Title:
Transiting planetary system WASP-17
Short Name:
J/MNRAS/426/1338
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present photometric observations of four transits in the WASP-17 planetary system, obtained using telescope defocusing techniques and with scatters reaching 0.5mmag per point. Our revised orbital period is 4.0+/-0.6s longer than previous measurements, a difference of 6.6{sigma}, and does not support the published detections of orbital eccentricity in this system. We model the light curves using the JKTEBOP code and calculate the physical properties of the system by recourse to five sets of theoretical stellar model predictions. The resulting planetary radius, Rb=1.932+/-0.052+/-0.010R_Jup_ (statistical and systematic errors, respectively), provides confirmation that WASP-17b is the largest planet currently known. All 14 planets with radii measured to be greater than 1.6R_Jup_are found around comparatively hot (T_eff_>5900K) and massive (M_A_>1.15M_{sun}_) stars. Chromospheric activity indicators are available for eight of these stars, and all imply a low activity level. The planets have small or zero orbital eccentricities, so tidal effects struggle to explain their large radii.
22346. Transiting planetary system WASP-4
ID:
ivo://CDS.VizieR/J/MNRAS/399/287
Title:
Transiting planetary system WASP-4
Short Name:
J/MNRAS/399/287
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present and analyse light curves of four transits of the Southern hemisphere extrasolar planetary system WASP-4, obtained with a telescope defocussed so the radius of each point spread function was 17 arcsec (44 pixels). This approach minimises both random and systematic errors, allowing us to achieve scatters of between 0.60 and 0.88mmag per observation over complete transit events. The light curves are augmented by published observations and analysed using the JKTEBOP code. The results of this process are combined with theoretical stellar model predictions to derive the physical properties of the WASP-4 system. WASP-4 is now one of the best-quantified transiting extrasolar planetary systems, and significant further progress requires improvements to our understanding of the physical properties of low-mass stars.
22347. Transiting planetary system WASP-5
ID:
ivo://CDS.VizieR/J/MNRAS/396/1023
Title:
Transiting planetary system WASP-5
Short Name:
J/MNRAS/396/1023
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54m telescope at ESO La Silla. In order to minimise both random and flat-fielding errors, we defocussed the telescope so its point spread function approximated an annulus of diameter 40 pixels (16 arcsec). Data reduction was undertaken using standard aperture photometry plus an algorithm for optimally combining the ensemble of comparison stars. The resulting light curves have point-to- point scatters of 0.50mmag for the first transit and 0.59mmag for the second. We construct detailed signal to noise calculations for defocussed photometry, and apply them to our observations. We model the light curves with the JKTEBOP code and combine the results with tabulated predictions from theoretical stellar evolutionary models to derive the physical properties of the WASP-5 system.
22348. Transiting planetary system WASP-2
ID:
ivo://CDS.VizieR/J/MNRAS/408/1680
Title:
Transiting planetary system WASP-2
Short Name:
J/MNRAS/408/1680
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present high-precision photometry of three transits of the extrasolar planetary system WASP-2, obtained by defocussing the telescope, and achieving point-to-point scatters of between 0.42 and 0.73mmag. These data are modelled using the JKTEBOP code, and taking into account the light from the recently-discovered faint star close to the system. The physical properties of the WASP-2 system are derived using tabulated predictions from five different sets of stellar evolutionary models, allowing both statistical and systematic error bars to be specified. We find the mass and radius of the planet to be M_b_=0.847+/-0.038+/-0.024M_jup_ and R_b_=1.044+/-0.029+/-0.015R_jup_. It has a low equilibrium temperature of 1280+/-21K, in agreement with a recent finding that it does not have an atmospheric temperature inversion.
22349. Transiting planetary system WASP-18
ID:
ivo://CDS.VizieR/J/ApJ/707/167
Title:
Transiting planetary system WASP-18
Short Name:
J/ApJ/707/167
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present high-precision photometry of five consecutive transits of WASP-18, an extrasolar planetary system with one of the shortest orbital periods known. Through the use of telescope defocussing we achieve a photometric precision of 0.47 to 0.83mmag per observation over complete transit events. The data are analysed using the JKTEBOP code and three different sets of stellar evolutionary models. We point out that seven of the nine known massive transiting planets have eccentric orbits, whereas significant orbital eccentricity has been detected for only four of the 46 less massive planets. This may indicate that there are two different populations of transiting planets, but could also be explained by observational biases. Further radial velocity observations of low-mass planets will make it possible to choose between these two scenarios.
22350. Transiting planetary system WASP-7
ID:
ivo://CDS.VizieR/J/A+A/527/A8
Title:
Transiting planetary system WASP-7
Short Name:
J/A+A/527/A8
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first high-precision photometry of the transiting extrasolar planetary system WASP-7, obtained using telescope defocussing techniques and reaching a scatter of 0.68mmag per point. We find that the transit depth is greater and that the host star is more evolved than previously thought. The planet has a significantly larger radius and much lower density and surface gravity than previous measurements showed. Based on the revised properties it is no longer an outlier in planetary mass-radius and period-gravity diagrams. We obtain a more precise transit ephemeris for the WASP-7 system.

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