目录
图像
上传图像
DSS Images Other Images
相关文章
Contribution à l'étude des spectres composites. VIII. HD 174016-7, une étoile Ap associée à une géante G Contribution to the study of composite spectra VIII. HD 174016-7, an Ap star with a giant G
HD 174016-7, listed by \cite[Hynek (1938)]{Hynek} as a star having acomposite spectrum, was on our observing programmes of such objectscarried out both at the Cambridge Observatories and at the ObservatoireMidi-Pyrénées. Most of the observations were made with theCORAVEL spectrovelocimeter of the Swiss telescope at the Observatoire deHaute-Provence. We find that this star is a long-period spectroscopicbinary with two correlation dips; we obtain the following orbitalelements: P = 3097.9 days; T = JD 2450605.2; omega = 204fdg 8; e =0.600; K_1 = 12.95 km s-1; K_2 = 15.14 km s-1; V_0= -1.65 km s-1; a_1 sin i = 441.1 Gm; a_2 sin i = 516.0 Gm;M_1 sin 3i = 1.967 M_sun; M_2sin 3i = 1.681 M_sun.The primary is a giant star of spectral type near G6III, and the hotdwarf secondary is found to be a peculiar A star of type A0p Sr, Cr, Eu,Si; so HD 174016-7 is, to our knowledge, the second discoveredcomposite-spectrum binary with a Ap-type hot component. A confrontationwith Hipparcos data suggests Mv_1 = 0 and m_v = 0.6 mag. Onthe basis of very accurate masses of main sequence stars by\cite[Andersen (1991),]{Andersen} we estimate the mass, M_1 = 2.8 M_sun,of the giant primary, the orbital inclination, i = 63o, andthe mean linear separation of the components, a = 7.2 AU. Theevolutionary status of the system is discussed using \cite[Schaller etal. (1992)]{Schaller} M_bol / T_eff diagram for stars of solarmetallicity. Theoretical masses suggested by this diagram confirm theproposed model. Étude effectuée à partird'observations faites aux Observatoires de Haute-Provence et deCambridge.
| Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
| Binaries among AP and AM stars
The results of long-term surveys of radial velocities of cool Ap and Amstars are presented. There are two samples, one of about 100 Ap starsand the other of 86 Am stars. Both have been observed with the CORAVELscanner from Observatoire de Haute-Provence (CNRS), France. Theconspicuous lack of short-period binaries among cool Ap stars seemsconfirmed, although this may be the result of an observational bias; onesystem has a period as short as 1.6 days. A dozen new orbits could bedetermined, including that of one SB2 system. Considering the massfunctions of 68 binaries from the literature and from our work, weconclude that the distribution of the mass ratios is the same for theBp-Ap stars than for normal G dwarfs. Among the Am stars, we found 52binaries, i.e. 60%; an orbit could be computed for 29 of them. Amongthese 29, there are 7 SB2 systems, one triple and one quadruple system.The 21 stars with an apparently constant radial velocity may show uplater as long-period binaries with a high eccentricity. The massfunctions of the SB1 systems are compatible with cool main-sequencecompanions, also suggested by ongoing spectral observations.
| Delta a and Stroemgren photometry of stars in the Renson-catalogue of AP and AM stars
We have observed 131 stars of \cite[Renson's (1991)]{re91} catalogue ofAp and Am stars both in the Stroemgren & Maitzen's (1976) Delta asystem as a contribution to the photometric studies of the lambda 5200broad band flux depression feature in chemically peculiar stars. Withfew exceptions the probability grouping of Renson for membership in theCP2 group of peculiar stars is nicely reflected by peculiar values ofDelta a. Comparison with already available Delta a values yieldsslightly larger values due to a minor shift in the filter g_1 samplingthe depression. As found by \cite[Maitzen & Vogt (1983)]{ma83} theGeneva system peculiarity parameters correlate well with Delta a. Thisstudy demonstrates the advantageous performance of a photoelectricphotometer with a rapidly rotating filter wheel moving in a stop and gomode. Tables 3 and 4 are also available in electronic form at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Spectral classifications in the near infrared of stars with composite spectra. II. Study of a sample of 180 stars
A sample of 180 supposedly composite-spectrum stars has been studied onthe basis of spectra obtained in the near infrared (8370-8780 Angstroms)at a dispersion of 33 Anstroms/mm. The objective was to study the coolercomponents of the systems. Of our sample, 120 are true compositespectra, 35 are hot spectra of types B, F and 25 are Am stars. We find astrong concentration of the cooler components of the composite spectraaround G8III. In view of the difficulty of classifying compositespectra, because of the super position of an early type dwarf and a latetype giant or supergiant spectrum, we have made several tests to controlthe classification based upon the infrared region. Since all tests gavepositive results, we conclude that our classifications can be consideredas being both reliable and homogeneous. Table \ref{tab1} is alsoavailable electronically at the CDS via anonymous ftp 130.79.128.5 orhttp://cdsweb.u-strasbg.fr/Abstracts.html} Based upon observationscarried out at Observatoire de Haute-Provence (CNRS).
| Contribution a l'etude des spectres composites. VI. HD 66068-9.
HD 66068-9 is listed by Hynek (1938) as a star having a compositespectrum. Classifications made by various authors and by us indicatethat this star is, in fact, an Am one. Our radial velocity observations,carried out at the Observatoire de Haute-Provence with thespectrovelocimeter CORAVEL, show HD 66068-9 to be a double-linedspectroscopic binary with the following orbital elements: P=7.74799days;T=2447600.690JD; ω=341.1deg; e=0.418; K_1_=56.1km/s;K_2_=75.1km/s; V_0_=-21.1km/s; a_1_sini=5.43x10^6^km;a_2_sini=7.27x10^6^km; M_1_sin^3^i=0.78Msun_;M_2_sin^3^i=0.58Msun_. The system appears to be a detachedone (a=~25Rsun_) without possibility of eclipses (i=~47deg);the secondary component should be an early F dwarf star. The ratio ofthe corelation dip areas indicates a blue magnitude difference{DELTA}m~1.6mag., and the dip area of the primary alone a metallicity[Fe/H]=~0.37dex for the Am star. Rotation-revolution synchronism isdiscussed: we conclude that this binary does not rotate synchronicallybut perhaps that pseudo-synchronization occurs near the periastronpassage, according to Hut's theory. Perturbations of some radialvelocities during 1983 suggest the existence of a long period thirdbody.
| Radial velocity measurements. I - Ground-based observations of the program stars for the HIPPARCOS satellite
The radial velocities of 272 stars brighter than m(pg) = 8.5 aredetermined by digital microphotometric measurement of plates obtainedwith dispersion 80 A/mm using the Marly slit spectrograph on the 120-cmtelescope of the Observatoire de Haute Provence. The objects wereselected as probable members of the input catalog for the ESA Hipparcosastrometric satellite. The measurement techniques and data-reductionprocedures are described in detail, and the results are presented inextensive tables and graphs and briefly characterized.
| Hyades and Sirius supercluster members brighter than magnitude (V) 7.1. II - Right ascension six to twelve hours
The present star sample is contained in the Bright Star Catalogue andits Supplement, augmented with a further supplement of 788 stars foundduring various observing programs over the past 40 years. Accurate,four-color and H-beta, or (RI), photometry is available for most of thesupercluster members. The criteria for membership are the comparisons ofthe proper motion, radial velocity, and luminosity obtained from thesupercluster parameters with the observed motions and the luminosityderived from the photometric parameters. New proper motions, based onall available catalogs, have been derived for the additional 788 starsdiscussed here, as well as all supercluster members.
| UBV photometry of stars whose positions are accurately known. II
The present report on the UBV observations of stars with favorableastrometric history gives attention to stars of the BD zones lyingbetween 50 and 54 deg. These observations and their reductions wereperformed from August 1983 to August 1984, as described by Oja (1984).Results are presented as tables for both the standard stars and theprogram stars. Comparisons are conducted between the present Vmagnitudes and those of the NPZT (1982) and AGK3R (1978) catalogs.
| Properties of AM stars in the Geneva photometric system
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&A....92..289H&db_key=AST
| Multicolor photometry of metallic-line stars. III. A photometric catalogue
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974RMxAA...1..175M&db_key=AST
| Catalogue of AM stars with known spectral types
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&AS...10..385H&db_key=AST
| Classification des spectres de 112 d'étoiles A et F dont 89 d'étoiles AM
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970A&AS....1....7B&db_key=AST
| New Metallic-Line A Stars
Not Available
| Slit Spectra of Some Peculiar and Metallic-Line A Stars
Not Available
| A survey of stars with composite spectra.
Not Available
|
提交文章
相关链接
提交链接
下列团体成员
|
观测天体数据
目录:
|
