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Pulkovo compilation of radial velocities for 35495 stars in a common system.
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| Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i
This work is the second part of the set of measurements of v sin i forA-type stars, begun by Royer et al. (\cite{Ror_02a}). Spectra of 249 B8to F2-type stars brighter than V=7 have been collected at Observatoirede Haute-Provence (OHP). Fourier transforms of several line profiles inthe range 4200-4600 Å are used to derive v sin i from thefrequency of the first zero. Statistical analysis of the sampleindicates that measurement error mainly depends on v sin i and thisrelative error of the rotational velocity is found to be about 5% onaverage. The systematic shift with respect to standard values fromSlettebak et al. (\cite{Slk_75}), previously found in the first paper,is here confirmed. Comparisons with data from the literature agree withour findings: v sin i values from Slettebak et al. are underestimatedand the relation between both scales follows a linear law ensuremath vsin inew = 1.03 v sin iold+7.7. Finally, thesedata are combined with those from the previous paper (Royer et al.\cite{Ror_02a}), together with the catalogue of Abt & Morrell(\cite{AbtMol95}). The resulting sample includes some 2150 stars withhomogenized rotational velocities. Based on observations made atObservatoire de Haute Provence (CNRS), France. Tables \ref{results} and\ref{merging} are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/897
| Rotational velocities of A-type stars. I. Measurement of v sin i in the southern hemisphere
Within the scope of a Key Programme determining fundamental parametersof stars observed by HIPPARCOS, spectra of 525 B8 to F2-type starsbrighter than V=8 have been collected at ESO. Fourier transforms ofseveral line profiles in the range 4200-4500 Å are used to derivev sin i from the frequency of the first zero. Statistical analysis ofthe sample indicates that measurement error is a function of v sin i andthis relative error of the rotational velocity is found to be about 6%on average. The results obtained are compared with data from theliterature. There is a systematic shift from standard values from\citet{Slk_75}, which are 10 to 12% lower than our findings. Comparisonswith other independent v sin i values tend to prove that those fromSlettebak et al. are underestimated. This effect is attributed to thepresence of binaries in the standard sample of Slettebak et al., and tothe model atmosphere they used. Based on observations made at theEuropean Southern Observatory (ESO), La Silla, Chile, in the frameworkof the Key Programme 5-004-43K. Table 4 is only available in electronicform at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5)or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/381/105
| delta Scuti stars in stellar systems: On the variability of HD 220392 and HD 220391
HD 220392 (HR 8895), the brightest member of the visual double star CCDM23239-5349, is a new short-period variable bright star, probably of thedelta Scuti type. The period analysis performed on the complete set ofdefinitive Geneva photometry as well as on the data obtained at the ESO0.5m telescope shows two periodicities of about 4.7 and 5.5 cycles perday (cpd) with amplitudes of 0.014 and 0.011 mag respectively. A similarperiod search on the (smaller) dataset obtained for the 1 mag fainterB-component, HD 220391, however shows no periodicity with an amplitudesignificantly above the noise level of the data (about 0.006 mag). Thisdifference in variability behaviour is discussed from the considerationthat both stars form a common origin pair and are located in the deltaScuti instability strip. Based on observations done at La Silla (ESO,Chile) and on data obtained by the Hipparcos astrometry satellite
| Radial velocities of HIPPARCOS southern B8-F2 type stars
Radial velocities have been determined for a sample of B8-F2 type starsobserved by the Hipparcos satellite. Observations were obtained withinthe framework of an ESO key-program. Radial velocities have beenmeasured using a cross-correlation method, the templates being a grid ofsynthetic spectra. The obtained precision depends on effectivetemperature and projected rotational velocity of the star as well as ona possible asymmetry of the correlation peak generally due to secondarycomponents. New spectroscopic binaries have been detected from theseasymmetries and the variability of the measured radial velocity.Simulations of binary and triple systems have been performed. Forbinaries our results have been compared with Hipparcos binary data.Adding the variable radial velocities, the minimum binary fraction hasbeen found 60% for physical systems. Radial velocities have beendetermined for 581 B8-F2 stars, 159 being new. Taking into accountpublished radial velocities, 39% south A-type stars with V magnitudelower than 7.5 have a radial velocity. Based on observations obtained atthe European Southern Observatory (ESO, La Silla, Chile) and on datafrom the ESA Hipparcos astrometry satellite.}\fnmsep \thanks{Tables 7, 8and 9 are only available in electronic form at the CDS via anonymous ftpto cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| The Delta Scuti-star HD 220392: A possible component of a binary system
Physical parameters and distances are determined for the stars HD 220391and HD 220392, which possibly form a physical pair. Ages andevolutionary masses in the new track system of Schaller et al. as wellas gravitational masses of both stars are evaluated. Distance and ageestimates of this possible binary system are obtained: 128(+/- 12) pcand 7.9(+/- 0.8) x 108 yr. Both stars are located within theDelta Scuti instability strip on the Hertzsprung-Russell (H-R) diagram,but a variability was only detected in HD 220392 by Lampens. Thepulsation mode(s) and the pulsation mass of this variable star cannot bedetermined at the present time.
| The early F-type stars - Refined classification, confrontation with Stromgren photometry, and the effects of rotation
The classification for early F-type stars in the MK spectralclassification system presented by Gray and Garrison (1987) is refined.The effect of rotation on spectral classification and ubvy-betaphotometry of early F-type stars is examined. It is found that theclassical luminosity criterion, the 4417 A/4481 A ratio givesinconsistent results. It is shown that most of the stars in the DeltaDelphini class of metallic-line stars are either normal or areindistinguishable from proto-Am stars. It is suggested that thedesignation Delta Delphini should be dropped. The classifications arecompared with Stromgren photometry. The effects of rotation on thedelta-c1 index in the early-F field dwarfs is demonstrated.
| A Note about the Comparison Between the Old and New Slettebak Systems of Axial Rotational Velocities
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984RMxAA...9....9G&db_key=AST
| Rotational velocities and spectral types for a sample of binary systems.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975A&AS...19...91L&db_key=AST
| Photovisual differences in magnitudes of 331 mainly southern double stars
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Besorolás csoportokba:
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Pozíciós és asztrometriai adatok
| Csillagkép: | Daru |
| Rektaszcenzió: | 23h23m52.94s |
| Deklináció: | -53°48'53.9" |
| Vizuális fényesség: | 7.046 |
| Távolság: | 108.814 parszek |
| RA sajátmozgás: | 74.6 |
| Dec sajátmozgás: | -30.7 |
| B-T magnitude: | 7.345 |
| V-T magnitude: | 7.071 |
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