- ID:
- ivo://CDS.VizieR/J/MNRAS/384/1444
- Title:
- Vr light curves of NGC 5466 RR Lyrae
- Short Name:
- J/MNRAS/384/1444
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of CCD V and r photometry of the globular cluster NGC 5466. The difference image analysis technique adopted in this work has resulted in accurate time series photometry even in crowded regions of the cluster enabling us to discover five probably semi-regular variables. We present new photometry of three previously known eclipsing binaries and six SX Phe stars. The light curves of the RR Lyrae stars have been decomposed in their Fourier harmonics and their fundamental physical parameters have been estimated using semi-empirical calibrations. The zero points of the metallicity, luminosity and temperature scales are discussed and our Fourier results are transformed accordingly. The average iron abundance and distance to the Sun derived from individual RR Lyrae stars, indicate values of [Fe/H]=-1.91+/-0.19 and D=16.0+/-0.6kpc, or a true distance modulus of 16.02+/-0.09mag, for the parent cluster. These values are respectively in the Zinn & West metallicity scale and in agreement with recent luminosity determinations for the RR Lyrae stars in the LMC. The M_V_-[Fe/H] relation has been recalibrated as M_V_=+(0.18+/-0.03)[Fe/H]+(0.85+/-0.05) using the mean values derived by the Fourier technique on RR Lyrae s tars in a family of clusters. This equation predicts M_V_=0.58mag for [Fe/H]=-1.5, in agreement with the average absolute magnitude of RR Lyrae stars calculated from several independent methods. The M_V-[Fe/H] relationship and the value of [Fe/H] have implications on the age of the globular clusters when determined from the magnitude difference between the horizontal branch and the turn off point (HB-TO method). The above results however would not imply a change in the age of NGC 5466, of 12.5+/-0.9Gyr, estimated from recent isochrone fitting.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/40.209
- Title:
- VR light curves of 15 RR Lyrae in NGC 4147
- Short Name:
- J/other/RMxAA/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of CCD V and R photometry of the RR Lyrae stars known in NGC 4147. The periodicities of most variables are revised and new ephemerides are calculated. The Blazhko effect has been detected in V2 and V6. Three previously reported variables; V5, V9, and V15 are found to be non-variable. A new variable V18 was discovered with a period of 0.49205-days and an amplitude of 0.15mag. Using the approach of Fourier decomposition of the light curves, the physical parameters of the RRab and RRc variables were estimated. The cluster is of the Oosterhoff type I. With the newly values [Fe/H]=-1.22+/-0.31 and 16.8+/-1.3kpc, the cluster fits very well into the Oosterhoff type-metallicity and metallicity-temperature sequence found in globular clusters. A comparison with ZAHB models indicates that the RRab stars have not yet evolved off the horizontal branch, a result consistent with the mean period of the RRab variables and with the metallicity of the cluster derived in this work.
- ID:
- ivo://CDS.VizieR/J/AJ/122/714
- Title:
- VR photometry of Century Survey galaxies
- Short Name:
- J/AJ/122/714
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 64{deg}^2^ of deep V and R CCD images to measure the local V- and R-band luminosity functions of galaxies. The V_0_<16.7 and R_0_<16.2 redshift samples contain 1255 and 1251 galaxies and are 98.1% and 98.2% complete, respectively.
- ID:
- ivo://CDS.VizieR/J/AcA/70/219
- Title:
- V1241 Tau and GQ Dra light curves
- Short Name:
- J/AcA/70/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric and spectroscopic observations and analyses for the eclipsing binary systems V1241 Tau and GQ Dra. Our photometric light and radial velocity curves analyses combining with the TESS light curves show that both are conventional semi--detached binary systems. Their absolute parameters are also derived. We present the O-C analyses of the systems and we propose the most possible orbital period modulating mechanisms. Furthermore, Fourier analyses are applied to the photometric residual data of the systems to check for the pulsational behavior of the components. We conclude that the primary component of the system GQ Dra is a delta Sct type pulsator with a dominant pulsation frequency of 18.58d^-1^ based on our B filter residual light curve although it can not be justified by 30-minute cadence TESS data. No satisfactory evidence of pulsational behaviour for V1241 Tau was verified. Finally, the evolutionary tracks of the components of both systems are calculated, while their locations within evolutionary diagrams are compared with other Algol-type systems.
- ID:
- ivo://CDS.VizieR/J/A+A/547/A61
- Title:
- WASP78 and WASP79 RV and photometric data
- Short Name:
- J/A+A/547/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of WASP-78b and WASP-79b, two highly-bloated Jupiter-mass exoplanets orbiting F-type host stars. WASP-78b orbits its V=12.0 host star (TYC 5889-271-1) every 2.175 days and WASP-79b orbits its V=10.1 host star (CD-30 1812) every 3.662 days. Planetary parameters have been determined using a simultaneous fit to WASP and TRAPPIST transit photometry and CORALIE radial-velocity measurements. For WASP-78b a planetary mass of 0.89+/-0.08M_Jup_ and a radius of 1.70+/-0.11R_Jup_ is found. The planetary equilibrium temperature of T_P_=2350+/-80K for WASP-78b makes it one of the hottest of the currently known exoplanets. WASP-79b its found to have a planetary mass of 0.90+/-0.08M_Jup_, but with a somewhat uncertain radius due to lack of sufficient TRAPPIST photometry. The planetary radius is at least 1.70+/-0.11R_Jup_, but could be as large as 2.09+/-0.14R_Jup_, which would make WASP-79b the largest known exoplanet.
- ID:
- ivo://CDS.VizieR/J/A+A/526/A130
- Title:
- WASP-34b photometry and radial velocities
- Short Name:
- J/A+A/526/A130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of WASP-34b, a sub-Jupiter-mass exoplanet transiting its 10.4-magnitude solar-type host star (1SWASP J110135.89-235138.4; TYC 6636-540-1) every 4.3177 days in a slightly eccentric orbit (e=0.038+/-0.012). We find a planetary mass of 0.59+/-0.01M_Jup_ and radius of 1.22^+0.11^_-0.08_R_Jup. There is a linear trend in the radial velocities of 55+/-4m/s/y indicating the presence of a long-period third body in the system with a mass >0.45M_Jup_ at a distance of >1.2AU from the host star. This third-body is either a low-mass star, white dwarf, or another planet. The transit depth ((R_P/R_*)^2^=0.0126) and high impact parameter (b=0.90) suggest that this could be the first known transiting exoplanet expected to undergo grazing transits, but with a confidence of only ~80%.
- ID:
- ivo://CDS.VizieR/J/A+A/520/A56
- Title:
- WASP-26b RV and photometric data
- Short Name:
- J/A+A/520/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of WASP-26b, a moderately over-sized Jupiter-mass exoplanet transiting its 11.3-mag early-G-type host star (1SWASP J001824.70-151602.3; TYC 5839-876-1) every 2.7566 days. A simultaneous fit to transit photometry and radial-velocity measurements yields a planetary mass of 1.02+/-0.03M_{Jup}_ and radius of 1.32+/-0.08R_{Jup}_. The host star, WASP-26, has a mass of 1.12+/-0.03 and a radius of 1.34+/-0.06 and is in a visual double with a fainter K-type star. The two stars are at least a common-proper motion pair with a common distance of around 250+/-15pc and an age of 6+/-2Gy.
688. WASP-12b transits
- ID:
- ivo://CDS.VizieR/J/A+A/528/A65
- Title:
- WASP-12b transits
- Short Name:
- J/A+A/528/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The transiting extrasolar planet WASP-12b was found to be the one of the most intensely irradiated exoplanets. It is unexpectedly bloated and is losing mass which may accrete into the host star. Our aim was to refine parameters of this intriguing system and search for signs of transit timing variations. We gathered high-precision light curves of two transits of WASP-12b. Assuming various limb darkening laws, we generated best-fitting models and redetermined parameters of the system. Error estimates were derived by the prayer bread method and Monte Carlo simulations. System's parameters obtained by us were found to agree with previous studies within one sigma. Use of the non-linear limb darkening laws resulted in the best- fitting models. With two new mid-transit times, the ephemeris was refined to BJD_TDB_=(2454508.97682+/-0.00020)+(1.09142245+/-0.00000033)E. Interestingly, indications for transit timing variation were detected at the level of 3.4 sigma. This signal could be induced by an additional planet in the system. Simplified numerical simulations showed that a perturber could be a terrestrial-type planet if both planets are in a low-order orbital resonance. However, we emphasise that further observations are needed to confirm variation and to put constraints on properties of the perturber.
- ID:
- ivo://CDS.VizieR/J/AcA/70/203
- Title:
- WASP-148 Ground-based Photometric Observations
- Short Name:
- J/AcA/70/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The WASP-148 planetary system has a rare architecture with a transiting Saturn-mass planet on a tight orbit which is accompanied by a slightly more massive planet on a nearby outer orbit. Using new space-born photometry and ground-based follow-up transit observations and data available in literature, we performed modeling that accounts for gravitational interactions between both planets. Thanks to the new transit timing data for planet b, uncertainties of orbital periods and eccentricities for both planets were reduced relative to previously published values by a factor of 3-4. Variation in transit timing has an amplitude of about 20 min and can be easily followed-up with a 1-m class telescopes from the ground. An approximated transit ephemeris, which accounts for gravitational interactions with an accuracy up to 5 min, is provided. No signature of transits was found for planet c down to the Neptune-size regime. No other transiting companions were found down to a size of about 2.4 Earth radii for interior orbits. We notice, however, that the regime of terrestrial-size planets still remains unexplored in that system.
- ID:
- ivo://CDS.VizieR/J/AcA/70/1
- Title:
- WASP-18 Photometric timeseries and timing data
- Short Name:
- J/AcA/70/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From its discovery, the WASP-18 system with its massive transiting planet on a tight orbit was identified as a unique laboratory for studies on tidal planet-star interactions. In an analysis of Doppler data, which include five new measurements obtained with the HIRES/Keck-I instrument between 2012 and 2018, we show that the radial velocity signal of the photosphere following the planetary tidal potential can be distilled for the host star. Its amplitude is in agreement with both theoretical predictions of the equilibrium tide approximation and an ellipsoidal modulation observed in an orbital phase curve. Assuming a circular orbit, we refine system parameters using photometric time series from TESS. With a new ground-based photometric observation, we extend the span of transit timing observations to 28 years in order to probe the rate of the orbital period shortening. Since we found no departure from a constant-period model, we conclude that the modified tidal quality parameter of the host star must be greater than 3.9e6 with 95% confidence. This result is in line with conclusions drawn from studies of the population of hot Jupiters, predicting that the efficiency of tidal dissipation is 1 or 2 orders of magnitude weaker. As the WASP-18 system is one of the prime candidates for detection of orbital decay, further timing observations are expected to push the boundaries of our knowledge on stellar interiors.
