- ID:
- ivo://CDS.VizieR/J/ApJ/629/507
- Title:
- Observed orbital eccentricities for 391 binaries
- Short Name:
- J/ApJ/629/507
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For 391 spectroscopic and visual binaries with known orbital elements and having B0-F0 IV or V primaries, we collected the derived eccentricities. As has been found by others, those binaries with periods of a few days have been circularized. However, those with periods up to about 1000 or more days show reduced eccentricities that asymptotically approach a mean value of 0.5 for the longest periods. For those binaries with periods greater than 1000 days their distribution of eccentricities is flat from 0 to nearly 1, indicating that in the formation of binaries there is no preferential eccentricity. The binaries with intermediate periods (10-100 days) lack highly eccentric orbits.
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Search Results
- ID:
- ivo://CDS.VizieR/J/PASP/107/299
- Title:
- Occultation Binaries Catalog
- Short Name:
- J/PASP/107/299
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observation of lunar occultation phenomena allows for the determination of binary star data which can not always be obtained using classical techniques. No complete catalog has been compiled since that of Evans (1981a) in spite of a 99% increase in the available data. This catalog presents a catalog of photoelectric and occultation measures of binary and multiple systems complete through 1994.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A57
- Title:
- ONC binary and triple stars
- Short Name:
- J/A+A/627/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recently published high-quality OmegaCAM photometry of the 3x3deg around the Orion Nebula Cluster (ONC) in r, and i filters revealed three well-separated pre-main sequences in the color-magnitude diagram (CMD). The objects belonging to the individual sequences are concentrated toward the center of the ONC. The authors concluded that there are two competitive scenarios: a population of unresolved binaries and triples with an exotic mass ratio distribution, or three stellar populations with different ages (~=1Myr age differences). We use Gaia DR2 in combination with the photometric OmegaCAM catalog to test and confirm the presence of the putative three stellar populations. We also study multiple stellar systems in the ONC for the first time using Gaia DR2. We selected ONC members based on parallaxes and proper motions and take advantage from OmegaCAM photometry that performs better than Gaia DR2 photometry in crowded regions. We identify two clearly separated sequences with a third suggested by the data. We used Pisa stellar isochrones to estimate ages of the stellar populations with absolute magnitudes computed using Gaia parallaxes on a star by star basis. (1) We confirm that the second and third sequence members are more centrally concentrated toward the center of the ONC. In addition we find an indication that the parallax and proper motion distributions are different among the members of the stellar sequences. The age difference among stellar populations is estimated to be 1-2Myr. (2) We use Gaia proper motions and other measures to identify and remove as many unresolved multiple system candidates as possible. Nevertheless we are still able to recover two well-separated sequences with evidence for the third one, supporting the existence of the three stellar populations. (3) Due to having ONC members with negligible fore- or background contamination we were able to identify a substantial number of wide binary objects (separation between 1000 and 3000 au) and with relative proper motions of the binary components consistent with zero. This challenges previously inferred values that suggested no wide binary stars exist in the ONC. Our inferred wide-binary fraction is ~=5%. We confirm the three populations correspond to three separated episodes of star formation. Based on this result, we conclude that star formation is not happening in a single burst in this region. In addition we identify 5% of wide-binary stars in the ONC that were thought not to be present.
- ID:
- ivo://CDS.VizieR/J/ApJ/727/102
- Title:
- On the frequency of Jupiter analogs
- Short Name:
- J/ApJ/727/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Anglo-Australian Planet Search has now accumulated 12 years of radial-velocity data with long-term instrumental precision better than 3m/s. In this paper, we expand on earlier simulation work, to probe the frequency of near-circular, long-period gas-giant planets residing at orbital distances of 3-6AU -the so-called Jupiter analogs. We present the first comprehensive analysis of the frequency of these objects based on radial-velocity data. We find that 3.3% of stars in our sample host Jupiter analogs; detailed, star-by-star simulations show that no more than 37% of stars host a giant planet between 3 and 6AU.
- ID:
- ivo://CDS.VizieR/J/A+A/537/A147
- Title:
- Optimizing exoplanet transit searches
- Short Name:
- J/A+A/537/A147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate a method to increase the efficiency of a targeted exoplanet search with the transit technique by preselecting a subset of candidates from large catalogs of stars. Assuming spin-orbit alignment, this can be achieved by considering stars that have a higher probability to be oriented nearly equator-on (inclination close to 90{deg}).
- ID:
- ivo://CDS.VizieR/J/ApJ/844/103
- Title:
- Orbit alignment in triple stars
- Short Name:
- J/ApJ/844/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The statistics of the angle {Phi} between orbital angular momenta in hierarchical triple systems with known inner visual or astrometric orbits are studied. A correlation between apparent revolution directions proves the partial orbit alignment known from earlier works. The alignment is strong in triples with outer projected separation less than ~50au, where the average {Phi} is about 20{deg}. In contrast, outer orbits wider than 1000 au are not aligned with the inner orbits. It is established that the orbit alignment decreases with the increasing mass of the primary component. The average eccentricity of inner orbits in well-aligned triples is smaller than in randomly aligned ones. These findings highlight the role of dissipative interactions with gas in defining the orbital architecture of low-mass triple systems. On the other hand, chaotic dynamics apparently played a role in shaping more massive hierarchies. The analysis of projected configurations and triples with known inner and outer orbits indicates that the distribution of {Phi} is likely bimodal, where 80% of triples have {Phi}<70{deg} and the remaining ones are randomly aligned.
- ID:
- ivo://CDS.VizieR/J/ApJS/214/17
- Title:
- Orbital monitoring of AstraLux binaries
- Short Name:
- J/ApJS/214/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Orbital monitoring of M-type binaries is essential for constraining their fundamental properties. This is particularly useful in young systems, where the extended pre-main-sequence evolution can allow for precise isochronal dating. Here, we present the continued astrometric monitoring of the more than 200 binaries of the AstraLux Large Multiplicity Survey, building both on our previous work, archival data, and new astrometric data spanning the range of 2010-2012. The sample is very young overall --all included stars have known X-ray emission, and a significant fraction (18%) of them have recently also been identified as members of young moving groups in the solar neighborhood. We identify ~30 targets that both have indications of being young and for which an orbit either has been closed or appears possible to close in a reasonable time frame (a few years to a few decades). One of these cases, GJ 4326, is, however, identified as probably being substantially older than has been implied from its apparent moving group membership, based on astrometric and isochronal arguments. With further astrometric monitoring, these targets will provide a set of empirical isochrones, against which theoretical isochrones can be calibrated, and which can be used to evaluate the precise ages of nearby young moving groups.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/209
- Title:
- Orbital nature of 81 ellipsoidal red giant binaries
- Short Name:
- J/ApJ/835/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we collect a sample of 81 ellipsoidal red giant binaries in the Large Magellanic Cloud (LMC), and we study their orbital natures individually and statistically. The sample contains 59 systems with circular orbits and 22 systems with eccentric orbits. We derive orbital solutions using the 2010 version of the Wilson-Devinney code (Wilson & Devinney 1971ApJ...166..605W ; Wilson 1979ApJ...234.1054W, 1990ApJ...356..613W ; Wilson+ 2009, J/ApJ/702/403). The sample is selection-bias corrected, and the orbital parameter distributions are compared to model predictions for the LMC and to observations in the solar vicinity. The masses of the red giant primaries are found to range from about 0.6 to 9M_{sun}_ with a peak at around 1.5M_{sun}_, in agreement with studies of the star formation history of the LMC, which find a burst of star formation beginning around 4 Gyr ago. The observed distribution of mass ratios q=m_2_/m_1_ is more consistent with the flat q distribution derived for the solar vicinity by Raghavan+ (2010, J/ApJS/190/1) than it is with the solar vicinity q distribution derived by Duquennoy & Mayor (1991A&A...248..485D). There is no evidence for an excess number of systems with equal mass components. We find that about 20% of the ellipsoidal binaries have eccentric orbits, twice the fraction estimated by Soszynski+ (2004, J/AcA/54/347). Our eccentricity evolution test shows that the existence of eccentric ellipsoidal red giant binaries on the upper parts of the red giant branch (RGB) can only be explained if tidal circularization rates are ~1/100 the rates given by the usual theory of tidal dissipation in convective stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/474/4322
- Title:
- Orbital parameters of 341 new binaries
- Short Name:
- J/MNRAS/474/4322
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The orbital parameters of binaries at intermediate periods (10^2^-10^3^d) are difficult to measure with conventional methods and are very incomplete. We have undertaken a new survey, applying our pulsation timing method to Kepler light curves of 2224 main-sequence A/F stars and found 341 non-eclipsing binaries. We calculate the orbital parameters for 317 PB1 systems (single-pulsator binaries) and 24 PB2s (double-pulsators), tripling the number of intermediate-mass binaries with full orbital solutions. The method reaches down to small mass ratios q~0.02 and yields a highly homogeneous sample. We parametrize the mass-ratio distribution using both inversion and MCMC forward-modelling techniques, and find it to be skewed towards low-mass companions, peaking at q~0.2. While solar-type primaries exhibit a brown dwarf desert across short and intermediate periods, we find a small but statistically significant (2.6{sigma}) population of extreme-mass-ratio companions (q<0.1}) to our intermediate-mass primaries. Across periods of 100-1500d and at q>0.1, we measure the binary fraction of current A/F primaries to be 15.4%+/-1.4%, though we find that a large fraction of the companions (21%+/-6%) are white dwarfs in post-mass-transfer systems with primaries that are now blue stragglers, some of which are the progenitors of Type Ia supernovae, barium stars, symbiotics, and related phenomena. Excluding these white dwarfs, we determine the binary fraction of original A/F primaries to be 13.9%+/-2.1% over the same parameter space. Combining our measurements with those in the literature, we find the binary fraction across these periods is a constant 5% for primaries M_1_<0.8M_{sun}_, but then increases linearly with logM_1_, demonstrating that natal discs around more massive protostars M_1_>~1M_{sun}_} become increasingly more prone to fragmentation. Finally, we find the eccentricity distribution of the main-sequence pairs to be much less eccentric than the thermal distribution.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1209
- Title:
- Orbits and system masses of 14 visual double stars
- Short Name:
- J/AJ/133/1209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents revised orbits and system masses of 14 visual double stars, in all of which at least one component is of early spectral type: WDS 00546+1911 (STT 20 AB), WDS 01040+3528 (HO 213), WDS 02039+4220 (STT 38 BC), WDS 03503+2535 (STT 65), WDS 06393+4200 (STT 150), WDS 08285-0231 (A551 AB), WDS 15088-4517 (SEE 219 AB), WDS 15416+1940 (HU 580 AB), WDS 16514+0113 (STT 315), WDS 17104-1544 (BU 1118 AB), WDS 19172-6640 (GLE 3), WDS 19411+1349 (KUI 93), WDS 22241-0450 (BU 172 AB), and WDS 23382+5514 (A1493). Star masses were calculated from Hipparcos parallax data whenever the precision was good enough (10 cases); otherwise, dynamical parallaxes were used, except in one case involving component multiplicity. Other physical and orbital properties of these stars are also discussed.