- ID:
- ivo://CDS.VizieR/J/MNRAS/447/711
- Title:
- Transiting planet WASP-103
- Short Name:
- J/MNRAS/447/711
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 17 transit light curves of the ultrashort period planetary system WASP-103, a strong candidate for the detection of tidally-induced orbital decay. We use these to establish a high-precision reference epoch for transit timing studies. The time of the reference transit mid-point is now measured to an accuracy of 4.8s, versus 67.4s in the discovery paper, aiding future searches for orbital decay. With the help of published spectroscopic measurements and theoretical stellar models, we determine the physical properties of the system to high precision and present a detailed error budget for these calculations. The planet has a Roche lobe filling factor of 0.58, leading to a significant asphericity; we correct its measured mass and mean density for this phenomenon. A high-resolution Lucky Imaging observation shows no evidence for faint stars close enough to contaminate the point spread function of WASP-103. Our data were obtained in the Bessell RI and the SDSS griz passbands and yield a larger planet radius at bluer optical wavelengths, to a confidence level of 7.3{sigma}. Interpreting this as an effect of Rayleigh scattering in the planetary atmosphere leads to a measurement of the planetary mass which is too small by a factor of 5, implying that Rayleigh scattering is not the main cause of the variation of radius with wavelength.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/450/1760
- Title:
- Transiting planet WASP-6b
- Short Name:
- J/MNRAS/450/1760
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present updates to prism, a photometric transit-starspot model, and gemc, a hybrid optimization code combining MCMC and a genetic algorithm. We then present high-precision photometry of four transits in the WASP-6 planetary system, two of which contain a starspot anomaly. All four transits were modelled using prism and gemc, and the physical properties of the system calculated. We find the mass and radius of the host star to be 0.836+/-0.063M_{sun}_ and 0.864+/-0.024R_{sun}_, respectively. For the planet, we find a mass of 0.485+/-0.027M_Jup_, a radius of 1.230+/-0.035R_Jup_ and a density of 0.244+/-0.014{rho}_Jup_. These values are consistent with those found in the literature. In the likely hypothesis that the two spot anomalies are caused by the same starspot or starspot complex, we measure the stars rotation period and velocity to be 23.80+/-0.15d and 1.78+/-0.20km/s, respectively, at a colatitude of 75.8{deg}. We find that the sky-projected angle between the stellar spin axis and the planetary orbital axis is {lambda}=7.2{deg}+/-3.7{deg}, indicating axial alignment. Our results are consistent with and more precise than published spectroscopic measurements of the Rossiter-McLaughlin effect. These results suggest that WASP-6 b formed at a much greater distance from its host star and suffered orbital decay through tidal interactions with the protoplanetary disc.
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/966
- Title:
- Transiting planet WASP-50b
- Short Name:
- J/MNRAS/431/966
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric observations of two transits in the WASP-50 planetary system, obtained using the ESO New Technology Telescope and the defocused-photometry technique. The rms scatters for the two data sets are 258 and 211 ppm with a cadence of 170-200s, setting a new record for ground-based photometric observations of a point source. The data were modelled and fitted using the prism and gemc codes, and the physical properties of the system calculated. We find the mass and radius of the hot star to be 0.861+/-0.057M{sun} and 0.855+/-0.019R{sun}, respectively. For the planet we find a mass of 1.437+/-0.068M_Jup_, a radius of 1.138+/-0.026R_Jup_ and a density of 0.911+/-0.033{rho}Jup. These values are consistent with but more precise than those found in the literature. We also obtain a new orbital ephemeris for the system: T_0_= BJD/TDB 2455558.61237(20)+1.9550938(13)xE.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/3671
- Title:
- Transiting planet WASP-19b
- Short Name:
- J/MNRAS/428/3671
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed a new model for analysing light curves of planetary transits when there are starspots on the stellar disc. Because the parameter space contains a profusion of local minima we developed a new optimization algorithm which combines the global minimization power of a genetic algorithm and the Bayesian statistical analysis of the Markov chain. With these tools we modelled three transit light curves of WASP-19. Two light curves were obtained on consecutive nights and contain anomalies which we confirm as being due to the same spot. Using these data we measure the star's rotation period and velocity to be 11.76+/-0.09d and 3.88+/-0.15km/s, respectively, at a latitude of 65{deg}. We find that the sky-projected angle between the stellar spin axis and the planetary orbital axis is {lambda} =1.0+/-1.2{deg}, indicating axial alignment. Our results are consistent with and more precise than published spectroscopic measurements of the Rossiter-McLaughlin effect.
- ID:
- ivo://CDS.VizieR/J/ApJ/736/12
- Title:
- Transit light curves of GJ1214
- Short Name:
- J/ApJ/736/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The super-Earth GJ1214b transits a nearby M dwarf that exhibits a 1% intrinsic variability in the near-infrared. Here, we analyze new observations to refine the physical properties of both the star and planet. We present three years of out-of-transit photometric monitoring of the stellar host GJ1214 from the MEarth Observatory and find the rotation period to be long, most likely an integer multiple of 53 days, suggesting low levels of magnetic activity and an old age for the system. We show that such variability will not pose significant problems to ongoing studies of the planet's atmosphere with transmission spectroscopy. We analyze two high-precision transit light curves from ESO's Very Large Telescope (VLT) along with seven others from the MEarth and Fred Lawrence Whipple Observatory 1.2m telescopes, finding physical parameters for the planet that are consistent with previous work. The VLT light curves show tentative evidence for spot occultations during transit. Using two years of MEarth light curves, we place limits on additional transiting planets around GJ1214 with periods out to the habitable zone of the system. We also improve upon the previous photographic V-band estimate for the star, finding V=14.71+/-0.03.
- ID:
- ivo://CDS.VizieR/J/AJ/143/95
- Title:
- Transit light curves of HAT-P-12
- Short Name:
- J/AJ/143/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric data of the transiting planet HAT-P-12b observed in 2011. Our three transit curves are modeled using the JKTEBOP code and adopting the quadratic limb-darkening law. Including our measurements, 18 transit times spanning about 4.2yr were used to determine the improved ephemeris with a transit epoch of 2454187.85560+/-0.00011BJD and an orbital period of 3.21305961+/-0.00000035days. The physical properties of the star-planet system are computed using empirical calibrations from eclipsing binary stars and stellar evolutionary models, combined with both our transit parameters and previously known spectroscopic results. We found that the absolute dimensions of the host star are M_A_=0.73+/-0.02M{sun}, R_A_=0.70+/-0.01R_{sun}_, log g_A_=4.61+/-0.02, p_A_=2.10+/-0.09{rho}{sun}, and L_A_=0.21+/-0.01L_{sun}_. The planetary companion has M_b_=0.21+/-0.01M_{Jup}_, R_b_=0.94+/-0.01R_{Jup}_, log g_b_=2.77+/-0.02, {rho}_b_=0.24+/-0.01{rho}_{Jup}_, and T_eq_=960+/-14K. Our results agree well with standard models of irradiated gas giants with a core mass of 11.3M_{earth}_.
- ID:
- ivo://CDS.VizieR/J/A+A/523/A84
- Title:
- Transit light curves of HAT-P-13b
- Short Name:
- J/A+A/523/A84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A possible transit of HAT-P-13c has been predicted to occur on 2010 April 28. Here we report on the results of a multi-site campaign that has been organised to detect the event. CCD photometric observations have been carried out at five observatories in five countries. We reached 30% time coverage in a 5 days interval centered on the suspected transit of HAT-P-13c. Two transits of HAT-P-13b were also observed. No transit of HAT-P-13c has been detected while the campaign was on. By a numerical experiment with 10^5^ model systems we conclude that HAT-P-13c is not a transiting exoplanet with a significance level from 65% to 72%, depending on the planet parameters and the prior assumptions. We present two times of transit of HAT-P-13b ocurring at BJD 2455141.5522+/-0.0010 and BJD 2455249.4508+/-0.0020. The TTV of HAT-P-13b is consistent with zero within 0.001 days. The refined orbital period of HAT-P-13b is 2.916293+/-0.000010 days.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1828
- Title:
- Transit light curves of HD 189733
- Short Name:
- J/AJ/133/1828
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry of HD 189733 during eight transits of its close-in giant planet, and out-of-transit photometry spanning 2yr. Using the transit photometry, we determine the stellar and planetary radii and the photometric ephemeris. Outside of transits, there are quasi-periodic flux variations with a 13.4-day period that we attribute to stellar rotation. In combination with previous results, we derive upper limits on the orbital eccentricity and on the true angle between the stellar rotation axis and planetary orbit (as opposed to the angle between the projections of those axes on the sky).
- ID:
- ivo://CDS.VizieR/J/A+A/535/A7
- Title:
- Transit light curves of WASP-10 b
- Short Name:
- J/A+A/535/A7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The WASP-10 planetary system is intriguing because different values of radius have been reported for its transiting exoplanet. The host star exhibits activity in terms of photometric variability, which is caused by the rotational modulation of the spots. Moreover, a periodic modulation has been discovered in transit timing of WASP-10 b, which could be a sign of an additional body perturbing the orbital motion of the transiting planet. We attempt to refine the physical parameters of the system, in particular the planetary radius, which is crucial for studying the internal structure of the transiting planet. We also determine new mid-transit times to confirm or refute observed anomalies in transit timing. We acquired high-precision light curves for four transits of WASP-10 b in 2010. Assuming various limb-darkening laws, we generated best-fit models and redetermined parameters of the system. The prayer-bead method and Monte Carlo simulations were used to derive error estimates. Three transit light curves exhibit signatures of the occultations of dark spots by the planet during its passage across the stellar disk. The influence of stellar activity on transit depth is taken into account while determining system parameters. The radius of WASP-10 b is found to be no greater than 1.03^+0.07^_-0.03_ Jupiter radii, a value significantly smaller than most previous studies indicate. We calculate interior structure models of the planet, assuming a two-layer structure with one homogeneous envelope atop a rock core. The high value of the WASP-10 b's mean density allows one to consider the planet's internal structure including 270 to 450 Earth masses of heavy elements. Our new mid-transit times confirm that transit timing cannot be explained by a constant period if all literature data points are considered. They are consistent with the ephemeris assuming a periodic variation of transit timing. We show that possible starspot features affecting the transit's ingress or egress cannot reproduce variations in transit timing at the observed amplitude.
- ID:
- ivo://CDS.VizieR/J/ApJ/812/46
- Title:
- Transit metric for Q1-Q17 Kepler candidates
- Short Name:
- J/ApJ/812/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a new metric that uses machine learning to determine if a periodic signal found in a photometric time series appears to be shaped like the signature of a transiting exoplanet. This metric uses dimensionality reduction and k-nearest neighbors to determine whether a given signal is sufficiently similar to known transits in the same data set. This metric is being used by the Kepler Robovetter to determine which signals should be part of the Q1-Q17 DR24 catalog of planetary candidates. The Kepler Mission reports roughly 20000 potential transiting signals with each run of its pipeline, yet only a few thousand appear to be sufficiently transit shaped to be part of the catalog. The other signals tend to be variable stars and instrumental noise. With this metric, we are able to remove more than 90% of the non-transiting signals while retaining more than 99% of the known planet candidates. When tested with injected transits, less than 1% are lost. This metric will enable the Kepler mission and future missions looking for transiting planets to rapidly and consistently find the best planetary candidates for follow-up and cataloging.
