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Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data
Context: .This paper is the last in a series devoted to the analysis ofthe binary content of the Hipparcos Catalogue. Aims: .Thecomparison of the proper motions constructed from positions spanning ashort (Hipparcos) or long time (Tycho-2) makes it possible to uncoverbinaries with periods of the order of or somewhat larger than the shorttime span (in this case, the 3 yr duration of the Hipparcos mission),since the unrecognised orbital motion will then add to the propermotion. Methods: .A list of candidate proper motion binaries isconstructed from a carefully designed χ2 test evaluatingthe statistical significance of the difference between the Tycho-2 andHipparcos proper motions for 103 134 stars in common between the twocatalogues (excluding components of visual systems). Since similar listsof proper-motion binaries have already been constructed, the presentpaper focuses on the evaluation of the detection efficiency ofproper-motion binaries, using different kinds of control data (mostlyradial velocities). The detection rate for entries from the NinthCatalogue of Spectroscopic Binary Orbits (S_B^9) is evaluated, as wellas for stars like barium stars, which are known to be all binaries, andfinally for spectroscopic binaries identified from radial velocity datain the Geneva-Copenhagen survey of F and G dwarfs in the solarneighbourhood. Results: .Proper motion binaries are efficientlydetected for systems with parallaxes in excess of ~20 mas, and periodsin the range 1000-30 000 d. The shortest periods in this range(1000-2000 d, i.e., once to twice the duration of the Hipparcos mission)may appear only as DMSA/G binaries (accelerated proper motion in theHipparcos Double and Multiple System Annex). Proper motion binariesdetected among S_B9 systems having periods shorter than about400 d hint at triple systems, the proper-motion binary involving acomponent with a longer orbital period. A list of 19 candidate triplesystems is provided. Binaries suspected of having low-mass(brown-dwarf-like) companions are listed as well. Among the 37 bariumstars with parallaxes larger than 5 mas, only 7 exhibit no evidence forduplicity whatsoever (be it spectroscopic or astrometric). Finally, thefraction of proper-motion binaries shows no significant variation amongthe various (regular) spectral classes, when due account is taken forthe detection biases.Full Table [see full textsee full text] is only available in electronicform at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/464/377
| Effective temperature scale and bolometric corrections from 2MASS photometry
We present a method to determine effective temperatures, angularsemi-diameters and bolometric corrections for population I and II FGKtype stars based on V and 2MASS IR photometry. Accurate calibration isaccomplished by using a sample of solar analogues, whose averagetemperature is assumed to be equal to the solar effective temperature of5777 K. By taking into account all possible sources of error we estimateassociated uncertainties to better than 1% in effective temperature andin the range 1.0-2.5% in angular semi-diameter for unreddened stars.Comparison of our new temperatures with other determinations extractedfrom the literature indicates, in general, remarkably good agreement.These results suggest that the effective temperaure scale of FGK starsis currently established with an accuracy better than 0.5%-1%. Theapplication of the method to a sample of 10 999 dwarfs in the Hipparcoscatalogue allows us to define temperature and bolometric correction (Kband) calibrations as a function of (V-K), [m/H] and log g. Bolometriccorrections in the V and K bands as a function of T_eff, [m/H] and log gare also given. We provide effective temperatures, angularsemi-diameters, radii and bolometric corrections in the V and K bandsfor the 10 999 FGK stars in our sample with the correspondinguncertainties.
| Differential Corrections Analysis of the UBVRI Observations of AG Phoenicis
The first photoelectric analysis of the Algol-like system AG Phe basedon U, B, V, R and I light curves and modeled using the Wilson andDevinney approach, is presented. The light curves are defined by 9246individual observations. The components and the orbit appears to bestable. The primary, more massive, more luminous and greater component,eclipsed (total transit) at primary minimum, is detached from its Rochelobe (79%). The secondary nearly fills its Roche lobe (99%) and has atemperature difference of Delta T=-3310 K. Preliminary derived absolutedimensions M_1/Modot=1.42, R_1/Rodot=1.66,L_1/Lodot=7.83, log g_1=4.15 assign normal MS characteristicsand a low degree of evolution to the A8V primary, whileM_2/Mȯ=0.22, R_2/Rodot=0.93, L_2/Lodot=0.29,log g_2=3.84 suggest an evolved K2 sub-giant secondary.
| A photometric orbit for the eclipsing binary AG Phoenicis
In each of the UBV bandpasses about 1760 observations define for thefirst time the photoelectric light variation of the binary system AGPhe. A consistent set of elements is derived in the framework of theclassical model. The system would be a well-detached binary consistingof two normal A9 and K0 main-sequence components.
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| Takýmyýldýz: | Anka |
| Sað Açýklýk: | 00h26m26.65s |
| Yükselim: | -39°42'03.8" |
| Görünürdeki Parlaklýk: | 9.057 |
| özdevim Sað Açýklýk: | -19.9 |
| özdevim Yükselim: | -1 |
| B-T magnitude: | 9.673 |
| V-T magnitude: | 9.108 |
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