New spectroscopic components in multiple systems. IV.

Tokovinin, Andreï; Gorynya, N. A.

doi:10.1051/0004-6361:20010714

Cited by 19 publications

(29 citation statements)

References 11 publications

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“…Table 2) is clear evidence against a case where one or both of the stars are significantly affected by further duplicity. We note that at least HR 5816 is known since long as a single-lined spectroscopic binary (Christie & Wilson 1938), but only recently Tokovinin & Gorynya (2001) determined a preliminary orbital period P ∼ 888 d and with their mass function and our primary mass in Table 2 a minimum secondary mass M B > 0.34 M (Fig. 10) is deduced.…”

Section: Two Pairs Of Visual Binariesmentioning

confidence: 65%

Nearby stars of the Galactic disk and halo. III.

2003

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Abstract. High-resolution spectroscopic observations of about 150 nearby stars or star systems are presented and discussed. The study of these and another 100 objects of the previous papers of this series implies that the Galaxy became reality 13 or 14 Gyr ago with the implementation of a massive, rotationally-supported population of thick-disk stars. The very high star formation rate in that phase gave rise to a rapid metal enrichment and an expulsion of gas in supernovae-driven Galactic winds, but was followed by a star formation gap for no less than three billion years at the Sun's galactocentric distance. In a second phase, then, the thin disk -our "familiar Milky Way" -came on stage. Nowadays it traces the bright side of the Galaxy, but it is also embedded in a huge coffin of dead thick-disk stars that account for a large amount of baryonic dark matter. As opposed to this, cold-dark-matter-dominated cosmologies that suggest a more gradual hierarchical buildup through mergers of minor structures, though popular, are a poor description for the Milky Way Galaxy -and by inference many other spirals as well -if, as the sample implies, the fossil records of its long-lived stars do not stick to this paradigm. Apart from this general picture that emerges with reference to the entire sample stars, a good deal of the present work is however also concerned with detailed discussions of many individual objects. Among the most interesting we mention the blue straggler or merger candidates HD 165401 and HD 137763/HD 137778, the likely accretion of a giant planet or brown dwarf on 59 Vir in its recent history, and HD 63433 that proves to be a young solar analog at τ ∼ 200 Myr. Likewise, the secondary to HR 4867, formerly suspected non-single from the Hipparcos astrometry, is directly detectable in the highresolution spectroscopic tracings, whereas the visual binary χ Cet is instead at least triple, and presumably even quadruple. With respect to the nearby young stars a complete account of the Ursa Major Association is presented, and we provide as well plain evidence for another, the "Hercules-Lyra Association", the likely existence of which was only realized in recent years. On account of its rotation, chemistry, and age we do confirm that the Sun is very typical among its G-type neighbors; as to its kinematics, it appears however not unlikely that the Sun's known low peculiar space velocity could indeed be the cause for the weak paleontological record of mass extinctions and major impact events on our parent planet during the most recent Galactic plane passage of the solar system. Although the significance of this correlation certainly remains a matter of debate for years to come, we point in this context to the principal importance of the thick disk for a complete census with respect to the local surface and volume densities. Other important effects that can be ascribed to this dark stellar population comprise (i) the observed plateau in the shape of the luminosity function of the local FGK stars, (ii) a small though syst...

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Section: Two Pairs Of Visual Binariesmentioning

confidence: 65%

Nearby stars of the Galactic disk and halo. III.

2003

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“…Further information on the observing method and its limitations can be found e.g. in (Tokovinin & Gorynya 2001). The RV precision reaches 0.3 km s −1 , but it is worse for stars with shallow correlation dips and/or fast axial rotation.…”

Section: Observationsmentioning

confidence: 99%

Spectroscopic orbits of nearby solar-type dwarfs – II.

Gorynya

Tokovinin

2017

Monthly Notices of the Royal Astronomical Society

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Several nearby solar-type dwarfs with variable radial velocity were monitored to find their spectroscopic orbits. First orbital elements of 15 binaries (HIP and 112222) are determined. The previously known orbits of HIP 5276, 21443, 28678, and 41214 are confirmed and updated. The orbital periods range from 2 days to 4 years. There are 8 hierarchical systems with additional distant companions among those 19 stars. The outer visual orbit of the triple system HIP 17895 is updated and the masses of all its components are estimated. We provide radial velocities of another 16 Hipparcos stars without orbital solutions, some of those with long periods or false claims of variability.

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“…-HIP 76603/2. The primary HIP 76603 = HD 139461 is itself a spectroscopic binary (preliminary orbit by Tokovinin & Gorynya 2001; P = 888 days, e = 0.9, K = 14 km s −1 ). The stars were also studied by Fuhrmann (2004).…”

Section: Individual Objectsmentioning

confidence: 99%

Abundance difference between components of wide binaries

Desidera¹,

Gratton²,

Lucatello³

et al. 2006

A&A

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Aims. We present high-precision iron abundance differences for 33 wide binaries with similar components. They were observed with the FEROS spectrograph at ESO, looking for abundance anomalies due to the ingestion of metal rich material of a planetary origin.Methods. An optimized data analysis technique and the high quality of the spectra allowed us to achieve an error of about 0.02 dex for pairs with small temperaure differences. Results. We found one case (HIP 64030 = HD 113984) with a large (0.27 dex) abundance difference. The primary of this binary appears to be a blue straggler, and the abundance difference might be due to the peculiar evolution of the star. A few other pairs show small abundance differences (≤0.09 dex). In a few cases these differences suggest the ingestion of a small amount of metal rich material, but in others they are likely spurious, because of the large temperature difference, high level of magnetic activity, or different evolutionary phases between the components. Some cases of abundance differences involving pairs with warm (T eff ≥ 6000 K) primaries might be due to the diffusion of heavy elements; dedicated theoretical models for the stellar parameters of the targets would be welcome. Conclusions. This study confirms our preliminary result based on analysis of 23 pairs (Desidera et al. 2004) that the occurrence of large alterations in stellar abundances caused by the ingestion of metal rich, rocky material is not a common event. For at least 65% of the pairs with components warmer than 5500 K, the limits on the amount of rocky material accreted by the program stars are comparable to the estimates of rocky material accreted by the Sun during its main-sequence lifetime.Key words. stars: abundances -stars: planetary systems -stars: binaries: visual -techniques: spectroscopic IntroductionWide visual binaries with similar components are ideal targets for high-precision differential abundance measurements. Gratton et al. (2001) and Desidera et al. (2004, hereafter Paper I) showed that errors in estimating the difference of iron content between the two components that are lower than 0.02 dex can be achieved for pairs with temperature differences smaller than 300−400 K and components with effective temperatures in the range 5300−6300 K. This opens possibilities for a detailed and quantitative study of chemical alterations in the external convective layer, which is caused by the accretion of metal-rich planetary material occurring during the main-sequence lifetime of the stars. In fact, the engulfment of 1 M ⊕ of iron (about 5 M ⊕ of meteoritic material) corresponds to an iron abundance difference of about 0.01 dex for a solar type main sequence star.Accretion phenomena have been suggested to explain the correlation between the presence of giant planets and the high metallicity of their parent stars (Gonzalez 1997). The most recent studies (Santos et al. 2004;Fischer & Valenti 2005) Based on observations collected at the European Southern Observatory, Chile, using FEROS spectrograp...

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New spectroscopic components in multiple systems. IV.

Cited by 19 publications

References 11 publications

Nearby stars of the Galactic disk and halo. III.

Nearby stars of the Galactic disk and halo. III.

Spectroscopic orbits of nearby solar-type dwarfs – II.

Abundance difference between components of wide binaries

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