- ID:
- ivo://CDS.VizieR/J/AZh/88/530
- Title:
- Dynamical study of ADS 12815
- Short Name:
- J/AZh/88/530
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A homogeneous series of photographic position measurements of the visual binary ADS 12815 obtained on the 26-inch refractor of the Pulkovo Observatory (1960-2007) is analyzed. The Pulkovo observations allow for the existence of the planet around component B discovered by Cochran et al. (1997ApJ...483..457C) based on radial-velocity measurements. The orbit of the planet must be steeply inclined to the plane of the sky (i>=70{deg}). Uniform series of position measurements obtained at the Dearborn Observatory, US Naval Observatory, and Pulkovo Observatory, the HIPPARCOS parallax, and the relative radial velocities obtained by Hauser andMarcy at the Lick Observatory are used to calculate the elements of possible orbits for the ADS 12815 stars using the apparent motion parameters method. The corresponding periods are more than 20000yr, the semi-major axes more than 900AU, and the eccentricities more than 0.65. All possible orbits are steeply inclined to the Galactic plane. The obtained family of orbits is in better agreement with observations than the family calculated by Hauser and Marcy.
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Search Results
- ID:
- ivo://CDS.VizieR/J/PAZh/34/446
- Title:
- Dynamical study of wide pairs of stars from WDS
- Short Name:
- J/PAZh/34/446
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the method of apparent motion parameters, we have studied the relative motion of the components in 561 pairs of wide (rho>2") and relatively nearby (Hipparcos parallaxes >0.01") visual double stars based on data from the WDS catalog. The minimum masses of the double stars have been calculated at given parallaxes. We have identified 358 optical pairs. For 11 stellar pairs, we have found the minimum mass to exceed the estimate corresponding to their spectral types and luminosities. This excess is 5-7M_{sun}_ for two stars, ADS7446 and 9701.
- ID:
- ivo://CDS.VizieR/J/AZh/82/231
- Title:
- Dynamic stability of selected multiple stars
- Short Name:
- J/AZh/82/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The abundances of chemical elements in the atmospheres of seven classical barium stars are derived.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A97
- Title:
- Early disc dispersal in close binaries
- Short Name:
- J/A+A/627/A97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Young (<600Myr) low-mass stars (M<~1M_{sun}_) of equal mass exhibit a distribution of rotation periods. At the very early phases of stellar evolution, this distribution is set by the star-disc locking mechanism, which forces stars to rotate at the same rate as the inner edge of the disc. The primordial disc lifetime and consequently the duration of the disc-locking mechanism, can be significantly shortened by the presence of a close companion, making the rotation period distribution of close binaries different from that of either single stars or wide binaries. We use new data to investigate and better constrain the range of ages, the components separation, and the mass ratio dependence at which the rotation period distribution has been significantly affected by the disc dispersal that is enhanced by close companions. We select a sample of close binaries in the Upper Scorpius association (age~8Myr) whose components have measured the separation and the rotation periods and compare their period distribution with that of coeval stars that are single stars. We find that components of close binaries have, on average, rotation periods that are shorter than those of single stars. More precisely, binaries with approximately equal-mass components (0.9<=M2/M1<=1.0) have rotation periods that are shorter than those of single stars by ~0.4d on average; the primary and secondary components of binaries with smaller mass ratios (0.8<M2/M1<0.9) have rotation periods that are shorter than those of single stars by ~1.9d and ~1.0d on average, respectively. A comparison with the older 25-Myr {beta} Pictoris association shows that whereas in the latter, all close binaries with projected separation {rho}<=80AU rotate faster than single stars, in the Upper Scorpius this is only the case for about 70% of stars. We interpret the enhanced rotation in close binaries with respect to single stars as the consequence of an early disc dispersal induced by the presence of close companions. The enhanced rotation suggests that disc dispersal timescales are longest for single stars and shorter for close binaries.
- ID:
- ivo://CDS.VizieR/J/MNRAS/401/257
- Title:
- Early-type binaries on main sequence
- Short Name:
- J/MNRAS/401/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We showed in a preceding paper based on an analysis of the observed rates of apsidal motion that synchronization in early-type eclipsing binaries continues on the main sequence, and the observed synchronization times, t_syn_, agree with the Zahn's theory (1977A&A....57..383Z) and are inconsistent with the shorter time-scale proposed by Tassoul (1987ApJ...322..856T, 1988ApJ...324L..71T). It follows from this that circularization in early-type binaries must also proceed in accordance with the Zahn's theory because the circularization times, t_circ_, in both theories are rather tightly related to tsyn via relation t_circ_~{alpha}t_syn_, where {alpha} is the orbital-to-axial momentum ratio.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/1278
- Title:
- Eccentricities of transiting planets
- Short Name:
- J/MNRAS/414/1278
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The two dominant features in the distribution of orbital parameters for close-in exoplanets are the prevalence of circular orbits for very short periods, and the observation that planets on closer orbits tend to be heavier. The first feature is interpreted as a signature of tidal evolution, while the origin of the second, a 'mass-period relation' for hot Jupiters, is not understood. In this paper we reconsider the ensemble properties of transiting exoplanets with well-measured parameters, focusing on orbital eccentricity and the mass-period relation. We recalculate the constraints on eccentricity in a homogeneous way, using new radial velocity data, with particular attention to statistical biases. We find that planets on circular orbits gather in a well-defined region of the mass-period plane, close to the minimum period for any given mass. Exceptions to this pattern reported in the literature can be attributed to statistical biases. The ensemble data is compatible with classical tide theory with orbital circularization caused by tides raised on the planet, and suggest that tidal circularization and the stopping mechanisms for close-in planets are closely related to each other. The position mass-period relation is compatible with a relation between a planet's Hill radius and its present orbit.
- ID:
- ivo://CDS.VizieR/J/MNRAS/456/2070
- Title:
- Eccentricity distribution of wide binaries
- Short Name:
- J/MNRAS/456/2070
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 477 solar-type binaries within 67pc with projected separations larger than 50AU is studied by a new statistical method. Speed and direction of the relative motion are determined from the short observed arcs or known orbits, and their joint distribution is compared to the numerical simulations. By inverting the observed distribution with the help of simulations, we find that average eccentricity of wide binaries is 0.59+/-0.02 and the eccentricity distribution can be modelled as f(e)~1.2e+0.4. However, wide binaries containing inner subsystems, i.e. triple or higher order multiples, have significantly smaller eccentricities with the average e=0.52+/-0.05 and the peak at e~0.5. We find that the catalogue of visual orbits is strongly biased against large eccentricities. A marginal evidence of eccentricity increasing with separation (or period) is found for this sample. Comparison with spectroscopic binaries proves the reality of the controversial period-eccentricity relation. The average eccentricity does increase with binary period, being 0.39 for periods from 10^2^ to 10^3^d and 0.59 for the binaries studied here (10^5^-10^6^d).
- ID:
- ivo://CDS.VizieR/J/ApJ/709/168
- Title:
- Eccentric orbits in exoplanets
- Short Name:
- J/ApJ/709/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Doppler technique measures the reflex radial motion of a star induced by the presence of companions and is the most successful method to detect exoplanets. If several planets are present, their signals will appear combined in the radial motion of the star, leading to potential misinterpretations of the data. Specifically, two planets in 2:1 resonant orbits can mimic the signal of a single planet in an eccentric orbit. We quantify the implications of this statistical degeneracy for a representative sample of the reported single exoplanets with available data sets, finding that (1) around 35% of the published eccentric one-planet solutions are statistically indistinguishable from planetary systems in 2:1 orbital resonance, (2) another 40% cannot be statistically distinguished from a circular orbital solution, and (3) planets with masses comparable to Earth could be hidden in known orbital solutions of eccentric super-Earths and Neptune mass planets.
- ID:
- ivo://CDS.VizieR/J/AJ/159/189
- Title:
- Eclipse timings for 9 contact binaries
- Short Name:
- J/AJ/159/189
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the first light curve synthesis and orbital period change analysis of nine contact binaries around the short-period limit. It is found that all these systems are W-subtype contact binaries. One of them is a medium contact system while the others are shallow contact ones. Four of them manifest obvious O'Connell effect explained by a dark spot or hot spot on one of the component stars. Third light was detected in three systems. By investigating orbital period variations, we found that four of the targets display a secular period decrease while the others exhibit a long-term period increase. The secular period decrease is more likely caused by angular-momentum loss while the long-term period increase is due to mass transfer from the less massive component to the more massive one. Based on the statistic of 19 ultrashort-period contact binaries with known orbital period changes, we found that seven of them display long-term decrease (three of them also exhibit cyclic variations), ten of them manifest long-term increase while two of them only show cyclic variation, and that most of them are shallow contact binaries supporting the long timescale angular-momentum loss theory suggested by Stepien. For the three deep contact systems, we found that they are probably triple systems. The tertiary companion plays an essential role during their formation and evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/506/491
- Title:
- Eclipsing binary candidates in Corot-IRa01 field
- Short Name:
- J/A+A/506/491
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CoRoT is a pioneering space mission devoted to the analysis of stellar variability and the photometric detection of extrasolar planets. We present the list of planetary transit candidates detected in the first field observed by CoRoT, IRa01, the initial run toward the Galactic anticenter, which lasted for 60 days. We analysed 3898 sources in the coloured bands and 5974 in the monochromatic band. Instrumental noise and stellar variability were taken into account using detrending tools before applying various transit search algorithms.
