- ID:
- ivo://CDS.VizieR/J/AZh/97/733
- Title:
- Binary Star Pop. with Common Proper Motion
- Short Name:
- J/AZh/97/733
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We describe a homogeneous catalog compilation of common proper motion stars based on GaiaDR2. A preliminary list of all pairs of stars within the radius of 100pc around the Sun with a separation less than a parsec was compiled. Also, a subset of comoving pairs, wide binary stars, was selected. The clusters and systems with multiplicity larger than 2 were excluded from consideration. The resulting catalog contains 10358 pairs of stars. The catalog selectivity function was estimated by comparison with a set of randomly selected field stars and with a model sample obtained by population synthesis. The estimates of the star masses in the catalogued objects, both components of which belong to the main-sequence, show an excess of ''twins'', composed by stars with similar masses. This excess decreases with increasing separation between components. It is shown that such an effect cannot be a consequence of the selectivity function only and does not appear in the model where star formation of similar masses is not artificially preferred. The article is based on the talk presented at the conference ''Astrometry yesterday, today, tomorrow'' (Sternberg Astronomical Institute of the Moscow State University, October 14 - 16, 2019).
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- ID:
- ivo://CDS.VizieR/J/MNRAS/473/4497
- Title:
- Binary stars astrom. and photom. measurements
- Short Name:
- J/MNRAS/473/4497
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The adaptive optics system at the 3.6m Advanced Electro-Optical System telescope was used to measure the astrometry and differential magnitude in I band of binary star systems between 2002 and 2006. We report 413 astrometric and photometric measurements of 373 stellar pairs. The astrometric measurements will be of use for future orbital determination, and the photometric measurements will be of use in estimating the spectral types of the component stars. For 21 binaries that had not been observed in decades, we are able to confirm that the systems share common proper motion. Candidate new companions were detected in 24 systems; for these we show the discovery images. Follow-up observations should be able to determine if these systems share common proper motion and are gravitationally bound objects. We computed orbits for nine binaries. Of these, the orbits of five systems are improved compared to prior orbits and four systems have their orbits computed for the first time. In addition, 315 stars were unresolved and the full-width half maxima of the images are presented.
- ID:
- ivo://CDS.VizieR/J/AJ/160/284
- Title:
- 2590 binary stars in Hipparcos and Gaia DR2
- Short Name:
- J/AJ/160/284
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- The Hipparcos catalog and its Double and Multiple System Annex (DMSA) lists 4099 components with individual proper motions and coordinates on the epoch 1991.25. Many of these long-period binary stars are also present in Gaia Data Release 2 (DR2). Using the available relative positions and proper motions separated by 24.25yr, the equations of relative orbital motion can be solved for the two epoch eccentric anomalies, orbital period, and eccentricity. This method employs elimination of the linear Thiele-Innes unknowns and nonlinear optimization of the remaining condition equations. The quality of these solutions is compromised by the insufficient condition and modest precision of the Hipparcos astrometric data, as revealed by Monte Carlo simulations with artificially perturbed data points. The presence of multiple systems and optical pairs can also perturb the results. Limited experiments with artificial data indicate that useful estimates can be obtained with a 25yr epoch difference for wide binaries with orbital periods up to ~500yr. The prospects of this method dramatically improve with the proposed next-generation space astrometry missions such as Gaia-NIR and Theia, especially when additional conditions are included from astrometric or spectroscopic measurements. An ancillary catalog of cross-identification and astrometric information for 1295 double-star pairs cross-matched in Gaia DR2 and Hipparcos is also published.
- ID:
- ivo://CDS.VizieR/J/AJ/159/15
- Title:
- Binary stars in Upper Scorpius
- Short Name:
- J/AJ/159/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To address the statistics of binary stars in the 8 Myr old Upper Scorpius (USco) star formation region, we conducted a speckle interferometric survey of 614 association members more massive than 0.4 M_{sun}_ (spectral types earlier than M3V) based on the list of Luhman et al. (2018, J/AJ/156/271). We resolved 187 pairs, 55 of which are new discoveries. Also using the published data and the Gaia DR2 (Cat. I/345), a catalog of 250 physical binaries was produced. We carefully estimated detection limits for each target and studied binary statistics in the separation range from 0.06" to 20" (9-2800 au), as well as clustering at larger separations. The frequency of companions with mass ratios q>0.3 in this separation range is 0.33+/-0.04 and 0.35+/-0.04 for early M- and solar-type stars, respectively, larger by 1.62+/-0.22 and 1.39+/-0.18 times compared to field stars of similar masses. The excess is produced mostly by pairs closer than 100 au. At separations from 100 to 10^4^ au, the separation distribution and companion fraction resemble those of solar-type stars in the field. However, unlike in the field, we see a relative deficit of equal-mass binaries at separations of ~500 au, compared to smaller and larger separations. The distribution of q depends on the separation, with a preference of larger q and a larger fraction of twins with q>0.95 at smaller separations. The binary population of USco differs from binaries in the field in several ways and suggests that binary statistics is not universal.
- ID:
- ivo://CDS.VizieR/J/A+AS/105/503
- Title:
- Binary star speckle measurements
- Short Name:
- J/A+AS/105/503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have continued to survey visual and interferometric binary stars with significant orbital motion by means of speckle method at the telescopes of the Special Astrophysical Observatory (SAO) in Zelenchuk. Here we present the lists of 267 speckle observations made with the 6 m and the 1 m telescopes in the period May 1989 - November 1993.
- ID:
- ivo://CDS.VizieR/J/A+AS/140/287
- Title:
- 1992-1997 binary star speckle measurements
- Short Name:
- J/A+AS/140/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of speckle interferometric measurements of binary stars made with the television photon-counting camera at the 6-m Big Azimuthal Telescope (BTA) and 1-m telescope of the Special Astrophysical Observatory (SAO) between August 1992 and May 1997. The data contain 89 observations of 62 star systems on the large telescope and 21 on the smaller one. For the 6-m aperture 18 systems remained unresolved. The measured angular separation ranged from 39 mas, two times above the BTA diffraction limit, to 1593 mas.
- ID:
- ivo://CDS.VizieR/J/PAZh/44/124
- Title:
- Binary systems among nearby dwarfs searching
- Short Name:
- J/PAZh/44/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our goal is to find previously unknown binary systems among low-mass dwarfs in the solar neighborhood and to test the search technique. The basic ideas are to reveal the images of stars with significant ellipticities and/or asymmetries compared to the background stars on CCD frames and to subsequently determine the spatial parameters of the binary system and the magnitude difference between its components. For its realization we have developed a method based on an image shapelet decomposition. All of the comparatively faint stars with large proper motions (Vmag>13^m^, {mu}>300mas/yr) for which the 'duplicate source' flag in the Gaia DR1 catalogue is equal to one have been included in the list of objects for our study. As a result, we have selected 702 stars. To verify our results, we have performed additional observations of 65 stars from this list with the Pulkovo 1-m 'Saturn' telescope (2016-2017). We have revealed a total of 138 binary candidates (nine of them from the `Saturn' telescope and SDSS data). Six program stars are known binaries. The images of the primaries of the comparatively wide pairs WDS 14519+5147, WDS 11371+6022, and WDS 15404+2500 are shown to be resolved into components; therefore, we can talk about the detection of triple systems. The angular separation {rho}, position angle, and component magnitude difference {Delta}m have been estimated for almost all of the revealed binary systems. For most stars 1.5''<{rho}<2.5'', while {Delta}m<1.5^m^.
- ID:
- ivo://CDS.VizieR/J/ApJ/745/19
- Title:
- Binary systems in Taurus-Auriga
- Short Name:
- J/ApJ/745/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The past decade has seen a revolution in our understanding of protoplanetary disk evolution and planet formation in single-star systems. However, the majority of solar-type stars form in binary systems, so the impact of binary companions on protoplanetary disks is an important element in our understanding of planet formation. We have compiled a combined multiplicity/disk census of Taurus-Auriga, plus a restricted sample of close binaries in other regions, in order to explore the role of multiplicity in disk evolution. Our results imply that the tidal influence of a close (<=40AU) binary companion significantly hastens the process of protoplanetary disk dispersal, as ~2/3 of all close binaries promptly disperse their disks within <~1Myr after formation. However, prompt disk dispersal only occurs for a small fraction of wide binaries and single stars, with ~80%-90% retaining their disks for at least ~2-3Myr (but rarely for more than ~5Myr). Our new constraints on the disk clearing timescale have significant implications for giant planet formation; most single stars have 3-5Myr within which to form giant planets, whereas most close binary systems would have to form giant planets within <~1Myr. If core accretion is the primary mode for giant planet formation, then gas giants in close binaries should be rare. Conversely, since almost all single stars have a similar period of time within which to form gas giants, their relative rarity in radial velocity (RV) surveys indicates either that the giant planet formation timescale is very well matched to the disk dispersal timescale or that features beyond the disk lifetime set the likelihood of giant planet formation.
- ID:
- ivo://CDS.VizieR/J/ApJ/794/35
- Title:
- Binary white dwarfs atmospheric parameters
- Short Name:
- J/ApJ/794/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed spectroscopic analysis of 61 low-mass white dwarfs and provide precise atmospheric parameters, masses, and updated binary system parameters based on our new model atmosphere grids and the most recent evolutionary model calculations. For the first time, we measure systematic abundances of He, Ca, and Mg for metal-rich, extremely low mass white dwarfs and examine the distribution of these abundances as a function of effective temperature and mass. Based on our preliminary results, we discuss the possibility that shell flashes may be responsible for the presence of the observed He and metals. We compare stellar radii derived from our spectroscopic analysis to model-independent measurements and find good agreement except for white dwarfs with T_eff_<~10000 K. We also calculate the expected gravitational wave strain for each system and discuss their significance to the eLISA space-borne gravitational wave observatory. Finally, we provide an update on the instability strip of extremely low mass white dwarf pulsators.
- ID:
- ivo://CDS.VizieR/J/AJ/161/160
- Title:
- BINOCS: NEWFIRM & IRAC IR photometry of clusters
- Short Name:
- J/AJ/161/160
- Date:
- 18 Jan 2022
- Publisher:
- CDS
- Description:
- We introduce a new binary detection technique, Binary INformation from Open Clusters using SEDs (binocs), which we show is able to determine reliable stellar multiplicity and masses over a much larger mass range than current approaches. This new technique determines accurate component masses of binary and single systems of the open clusters' main sequence by comparing observed magnitudes from multiple photometric filters to synthetic star spectral energy distributions (SEDs), allowing us to systematically probe the binary population for low-mass stars in clusters for eight well-studied open clusters. We provide new deep, infrared photometric catalogs (1.2-8.0 {mu}m) for the key open clusters NGC 1960 (M36), NGC 2099 (M37), NGC 2420, and NGC 2682 (M67), using observations from NOAO/NEWFIRM and Spitzer/IRAC. Using these deep multiwavelength catalogs, the binocs method is applied to these clusters to determine accurate component masses for unresolved cluster binaries. We explore binary fractions as a function of cluster age, Galactic location, and metallicity.
