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1371. Transit light curves of HAT-P-13b
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.
1372. Transit light curves of HD 189733
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).
1373. Transit of exoplanet HD 17156b
ID:
ivo://CDS.VizieR/J/ApJ/693/794
Title:
Transit of exoplanet HD 17156b
Short Name:
J/ApJ/693/794
Date:
21 Oct 2021
Publisher:
CDS
Description:
Photometry is presented of the 2007 December 25 transit of HD 17156b, which has the longest orbital period and highest orbital eccentricity of all the known transiting exoplanets. New measurements of the stellar radial velocity are also presented. All the data are combined and integrated with stellar-evolutionary modeling to derive refined system parameters.
1374. Transits of exoplanet XO-3b
ID:
ivo://CDS.VizieR/J/ApJ/683/1076
Title:
Transits of exoplanet XO-3b
Short Name:
J/ApJ/683/1076
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present photometry of 13 transits of XO-3b, a massive transiting planet on an eccentric orbit. Previous data led to two inconsistent estimates of the planetary radius. Our data strongly favor the smaller radius, with increased precision: R_p_=1.217+/-0.073R_{sun}_. A conflict remains between the mean stellar density determined from the light curve, and the stellar surface gravity determined from the shapes of spectral lines. We argue the light curve should take precedence, and revise the system parameters accordingly. The planetary radius is about 1{sigma} larger than the theoretical radius for a hydrogen-helium planet of the given mass and insolation. To help in planning future observations, we provide refined transit and occultation ephemerides.
1375. Transits of TrES-4b, HAT-P-3b and WASP-12b
ID:
ivo://CDS.VizieR/J/AJ/141/179
Title:
Transits of TrES-4b, HAT-P-3b and WASP-12b
Short Name:
J/AJ/141/179
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present transit photometry of three exoplanets, TrES-4b, HAT-P-3b, and WASP-12b, allowing for refined estimates of the systems' parameters. TrES-4b and WASP-12b were confirmed to be "bloated" planets, with radii of 1.706+/-0.056R_Jup_ and 1.736+/-0.092R_Jup_, respectively. These planets are too large to be explained with standard models of gas giant planets. In contrast, HAT-P-3b has a radius of 0.827+/-0.055R_Jup_, smaller than a pure hydrogen-helium planet and indicative of a highly metal-enriched composition. Analyses of the transit timings revealed no significant departures from strict periodicity. For TrES-4, our relatively recent observations allow for improvement in the orbital ephemerides, which is useful for planning future observations.
1376. Transits of WASP-33
ID:
ivo://CDS.VizieR/J/A+A/526/L10
Title:
Transits of WASP-33
Short Name:
J/A+A/526/L10
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of photometric oscillations in the host star of the exoplanet WASP-33b (HD 15082). The data were obtained in the R band in both transit and out-of-transit phases from the 0.3-m telescope and the Montcabrer Observatory and the 0.8-m telescope at the Montsec Astronomical Observatory. Proper fitting and subsequent removal of the transit signal reveals stellar photometric variations with a semi-amplitude of about 1mmag. The detailed analysis of the periodogram yields a structure of significant signals around a frequency of 21 cyc per day, which is typical of delta Scuti-type variable stars. An accurate study of the power spectrum reveals a possible commensurability with the planet orbital motion with a factor of 26, but this remains to be confirmed with additional time-series data that will permit the identification of the significant frequencies. These findings make WASP-33 the first transiting exoplanet host star with delta Scutt variability and a very interesting candidate to search for star-planet interactions.
1377. 65 Transit-timing variation planets properties
ID:
ivo://CDS.VizieR/J/AJ/162/55
Title:
65 Transit-timing variation planets properties
Short Name:
J/AJ/162/55
Date:
16 Mar 2022 00:18:00
Publisher:
CDS
Description:
Transit surveys have revealed a significant population of compact multiplanet systems, containing several sub-Neptune-mass planets on close-in, tightly-packed orbits. These systems are thought to have formed through a final phase of giant impacts, which would tend to leave systems close to the edge of stability. Here, we assess this hypothesis, comparing observed eccentricities in systems exhibiting transit-timing variations versus the maximum eccentricities compatible with long-term stability. We use the machine-learning classifier SPOCK (Tamayo et al.) to rapidly classify the stability of numerous initial configurations and hence determine these stability limits. While previous studies have argued that multiplanet systems are often maximally packed, in the sense that they could not host any additional planets, we find that the existing planets in these systems have measured eccentricities below the limits allowed by stability by a factor of 2-10. We compare these results against predictions from the giant-impact theory of planet formation, derived from both N-body integrations and theoretical expectations that, in the absence of dissipation, the orbits of such planets should be distributed uniformly throughout the phase space volume allowed by stability. We find that the observed systems have systematically lower eccentricities than this scenario predicts, with a median eccentricity about four times lower than predicted. This suggests that, if these systems formed through giant impacts, then some dissipation must occur to damp their eccentricities. This may occur through interactions with the natal gas disk or a leftover population of planetesimals, or over longer timescales through the coupling of tidal and secular processes.
1378. T Tauri binary systems orbital motion
ID:
ivo://CDS.VizieR/J/A+A/369/249
Title:
T Tauri binary systems orbital motion
Short Name:
J/A+A/369/249
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using speckle-interferometry we have carried out repeated measurements of relative positions for the components of 34 T Tauri binary systems. The projected separation of these components is low enough that orbital motion is expected to be observable within a few years. In most cases orbital motion has indeed been detected. The observational data is discussed in a manner similar to Ghez et al. (1995AJ....110..753G). However, we extend their study to a larger number of objects and a much longer timespan. The database presented in this paper is valuable for future visual orbit determinations. It will yield empirical masses for T Tauri stars that now are only poorly known. The available data is however not sufficient to do this at the present time. Instead, we use short series of orbital data and statistical distributions of orbital parameters to derive an average system mass that is independent of theoretical assumptions about the physics of PMS stars. For our sample this mass is and thus in the order of magnitude one expects for the mass sum of two T Tauri stars. It is also comparable to mass estimates obtained for the same systems using theoretical PMS evolutionary models.
1379. TU UMa light curves and maxima, CL Aur minima
ID:
ivo://CDS.VizieR/J/A+A/589/A94
Title:
TU UMa light curves and maxima, CL Aur minima
Short Name:
J/A+A/589/A94
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recent statistical studies prove that the percentage of RR Lyrae pulsators that are located in binaries or multiple stellar systems is considerably lower than might be expected. This can be better understood from an in-depth analysis of individual candidates. We investigate in detail the light time effect of the most probable binary candidate TU UMa. This is complicated because the pulsation period shows secular variation. We model possible light time effect of TU UMa using a new code applied on previously available and newly determined maxima timings to confirm binarity and refine parameters of the orbit of the RRab component in the binary system. The binary hypothesis is also tested using radial velocity measurements. We used new approach to determine brightness maxima timings based on template fitting. This can also be used on sparse or scattered data. This approach was successfully applied on measurements from different sources. To determine the orbital parameters of the double star TU UMa, we developed a new code to analyse light time effect that also includes secular variation in the pulsation period. Its usability was successfully tested on CL Aur, an eclipsing binary with mass-transfer in a triple system that shows similar changes in the O-C diagram. Since orbital motion would cause systematic shifts in mean radial velocities (dominated by pulsations), we computed and compared our model with centre-of-mass velocities. They were determined using high-quality templates of radial velocity curves of RRab stars. Maxima timings adopted from the GEOS database (168) together with those newly determined from sky surveys and new measurements (85) were used to construct an O-C diagram spanning almost five proposed orbital cycles. This data set is three times larger than data sets used by previous authors. Modelling of the O-C dependence resulted in 23.3-year orbital period, which translates into a minimum mass of the second component of about 0.33Ms. Secular changes in the pulsation period of TU UMa over the whole O-C diagram were satisfactorily approximated by a parabolic trend with a rate of -2.2ms/yr. To confirm binarity, we used radial velocity measurements from nine independent sources. Although our results are convincing, additional long-term monitoring is necessary to unambiguously confirm the binarity of TU UMa.
1380. TV Boo V light curve
ID:
ivo://CDS.VizieR/J/MNRAS/428/1442
Title:
TV Boo V light curve
Short Name:
J/MNRAS/428/1442
Date:
21 Oct 2021
Publisher:
CDS
Description:
This study investigates periodic modulation of the light curve of the RRc star TV Boo and its physical parameters based on photometric data. This phenomenon, known as the Blazhko effect, is quite rare among RRc stars. The frequency analysis based on the data gathered at the Masaryk University Observatory (MUO) and also using SuperWASP data revealed symmetrically structured peaks around the main pulsation frequency and its harmonics, which indicate two modulation components of the Blazhko period. The main modulation periodicity was found to be 9.7374+/-0.0054d. This is one of the shortest known Blazhko periods among RRc stars. The second modulation period (21.5+/-0.2d) causes changes of the Blazhko effect itself. Some indices show that TV Boo could be affected by long-term changes of the order of years. Basic physical parameters were estimated via an MUO V light-curve solution using Fourier parameters. TV Boo seems to be a low-metallicity star with [Fe/H]=-1.89.