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HD 16769



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Observed Orbital Eccentricities
For 391 spectroscopic and visual binaries with known orbital elementsand having B0-F0 IV or V primaries, we collected the derivedeccentricities. As has been found by others, those binaries with periodsof a few days have been circularized. However, those with periods up toabout 1000 or more days show reduced eccentricities that asymptoticallyapproach a mean value of 0.5 for the longest periods. For those binarieswith periods greater than 1000 days their distribution of eccentricitiesis flat from 0 to nearly 1, indicating that in the formation of binariesthere is no preferential eccentricity. The binaries with intermediateperiods (10-100 days) lack highly eccentric orbits.

Tidal Effects in Binaries of Various Periods
We found in the published literature the rotational velocities for 162B0-B9.5, 152 A0-A5, and 86 A6-F0 stars, all of luminosity classes V orIV, that are in spectroscopic or visual binaries with known orbitalelements. The data show that stars in binaries with periods of less thanabout 4 days have synchronized rotational and orbital motions. Stars inbinaries with periods of more than about 500 days have the samerotational velocities as single stars. However, the primaries inbinaries with periods of between 4 and 500 days have substantiallysmaller rotational velocities than single stars, implying that they havelost one-third to two-thirds of their angular momentum, presumablybecause of tidal interactions. The angular momentum losses increase withdecreasing binary separations or periods and increase with increasingage or decreasing mass.

Observational survey of the puzzling star HD 179821: Photometric variations and period analysis
From new photometric observations (UBVRI), we present the characteristicfeatures of the light variations of the evolved star HD 179821 (= SAO124414 = IRAS 19114+0002). Our data, collected through 1999 and 2000,have been combined together with previous photometric measurementsavailable in the literature. Thus, a long term V-light curve (gatheringmore than 10 years of observations for HD 179821) has been composed. Wehave analysed it with the Fourier transform method. Two main frequenciesare present in the resulting power spectrum, reflecting a dominantbimodal pulsator behavior. A long term phenomenon is also found, but itis not possible to decide whether it is periodic. The Fourier analysishas also been applied on two other filters (U and B) and confirms thedetected frequencies. On the basis of our period analysis, we discussthe nature of HD 179821: low-mass post-AGB star or high-mass star.based on observations carried out at the Observatoire de Haute Provence,France, operated by the Centre National de la Recherche Scientifique(CNRS).

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 ( or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/897

Short-Period Light Variation of an Eclipsing Binary System: RZ Cassiopeiae
The eclipsing binary system RZ Cas is known to exhibit variation in itslight curves at the primary minimum, usually showing apartial-eclipse-type curve but sometimes indicating a flat minimum,which is evidence for a total eclipse. We observed RZ Cas not onlyduring the primary eclipse, but also during the out-of-eclipse phase,and we have found a short-period light variation with a frequency of62.20 cycles day-1 (period of 23.15 minutes), whose maximumamplitude is 0.02 mag. This short-period variation can modulate theshape of the light curve at the primary minimum effectively. Thebrightness-color relationship of the short-period variation suggests aδ Scuti type oscillation.

The proper motions of fundamental stars. I. 1535 stars from the Basic FK5
A direct combination of the positions given in the HIPPARCOS cataloguewith astrometric ground-based catalogues having epochs later than 1939allows us to obtain new proper motions for the 1535 stars of the BasicFK5. The results are presented as the catalogue Proper Motions ofFundamental Stars (PMFS), Part I. The median precision of the propermotions is 0.5 mas/year for mu alpha cos delta and 0.7mas/year for mu delta . The non-linear motions of thephotocentres of a few hundred astrometric binaries are separated intotheir linear and elliptic motions. Since the PMFS proper motions do notinclude the information given by the proper motions from othercatalogues (HIPPARCOS, FK5, FK6, etc.) this catalogue can be used as anindependent source of the proper motions of the fundamental stars.Catalogue (Table 3) is only available at the CDS via anonymous ftp tocdsarc.u-strasbg.fr ( or viahttp://cdsweb.u-strastg.fr/cgi-bin/qcat?J/A+A/365/222

On the Variability of A3-F0 Luminosity Class III-V Stars
I investigate the Hipparcos Satellite photometry of A3-F0 stars ofluminosity classes III-V to learn about their variability and identify afew stars for which further study is desirable.

Analyses of the Short-Period Cepheid SU Cassiopeiae
Baade-Wesselink analyses of this important Galactic classical Cepheidprovide new values for the radius, luminosity, distance, and mass andshow SU Cas likely to be pulsating in the first overtone. Application ofa modified Baade-Wesselink technique and the maximum likelihood method,which we have previously applied to δ Scuti-type variables, yieldvalues of R=33.0+/-1.1 Rsolar, L=1536+/-291Lsolar, MV=-3.28-0.19+0.23, r=486+/-52 pc,mass (from the Baade-Wesselink radius), M=6.5+/-0.6 Msolar(assuming first-overtone pulsation), and evolutionary mass,Mev=5.5+/-0.3 Msolar. The results are consistentwith the Hipparcos satellite parallax, 2.31+/-0.58 mas(433+145-87 pc), providing further support forovertone pulsation of SU Cas. In the course of the analyses, amodification to the maximum likelihood method, devised by one of us (W.J. F. W.), is presented as an alternative to the modifications of Laney& Stobie and Coulson, Caldwell, & Gieren. We dedicate this paper toAdriaan J. Wesselink, a dedicated scientist and teacher, and inventor of``the method.''

Detection of the delta Scuti Oscillation in RZ Cassiopeiae
PMT and CCD photometry of the RZ Cas were carried out. The 22-minperiodic oscillations with amplitude of about 20-mmag amplitude weredetected not only in primary minimum but also in secondary minimum andin out-of-eclipse. The oscillations should be the Delta Scutivariability.

Near-Infrared Photometric Studies of RZ Cassiopeiae
Light curves of the Algol-type binary system, RZ Cassiopeiae, in thenear-IR wavelengths J and K are obtained for the first time. The lightcurves are analyzed using the Wilson-Devinney model. UBV light curves ofRZ Cas obtained by Chambliss are also reanalyzed using the same program.In the J and K bands, the bolometric albedo of the secondary of RZ Casexhibited values above 0.7, whereas the theoretically expected value forsuch a star is 0.5. Also, the values of the secondary temperaturederived from the J and K light curves are found to be less than thatderived from our analysis of the optical light curves as well as fromthe previous studies in the optical photometric bands. We have attemptedto model these effects with a dark spot on the secondary of RZ Cas. TheJ-band light curve gave a better fit with a cool dark spot on thesecondary. Another possible reason for the above mentioned effects is agas stream from the lobe-filling secondary to the primary star. Themagnitudes and colors of the individual components are derived from theobserved light curves and the light contributions from the stars derivedfrom the light curve analysis. The primary is found to be an A3 V staras observed by previous investigators. The secondary is classified asK0-K4 IV from the derived colors. Seven epochs of primary minima and 3epochs of secondary minima are obtained from the observations. Becauseof the increased depths of the secondary eclipse in the infrared bands,the moments of minima are calculated with nearly the same accuracy asthat of the primary minima. All the secondary minima are found to occurat phase 0.5. None of the observed primary minima are flat as found bymany observers before at optical wavelengths. The colors of the systemat the minima obtained by us confirm that the system is partiallyeclipsing.

New variable chemically peculiar stars identified in the HIPPARCOS archive
Since variability of chemically peculiar (CP) stars plays an importantrole for the astrophysical explanation of their outstanding behaviour,we have identified new variable CP stars listed in Renson's catalogueusing the extensive Hipparcos Variability Annex. From the 293 objectsfound, 33 were excluded because they are no CP stars and/or have noperiod listed, half of the remaining stars are newly identified and halfhad been already included in the catalogue of variable CP stars by\cite[Catalano & Renson (1997).]{Ca} Most of the newly identifiedvariability is due to an apparent magnetic field coupled with stellarrotation (oblique rotator model). The constraints of this model arefulfilled for all but three CP2 stars. Variations of bona fide Am-Fmstars are exclusively explained by eclipses of binary systems.Furthermore eight candidates of the >~mma Doradus group (pulsatingAm-Fm stars) were detected. Based on data from the ESA Hipparcosastrometry satellite. Table 1 is also available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr ( orvia\break http://cdsweb.u-strasbg.fr/Abstract.html

On the HIPPARCOS photometry of chemically peculiar B, A, and F stars
The Hipparcos photometry of the Chemically Peculiar main sequence B, A,and F stars is examined for variability. Some non-magnetic CP stars,Mercury-Manganese and metallic-line stars, which according to canonicalwisdom should not be variable, may be variable and are identified forfurther study. Some potentially important magnetic CP stars are noted.Tables 1, 2, and 3 are available only in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr ( or viahttp://cdsweb.u-strasbg.fr/Abstract.html

The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.

BVRI Observations of an eclipse of RZ Cas
BVRI photometry of an eclipse of the RZ Cas is reported.

Photometric Observations of the Primary Minimum of the Active Algol Binary RZ Cassiopeiae
Photoelectric and CCD observations of the primary minimum of the activeAlgol binary RZ Cas were carried out. The observed times of the primaryminima are estimated and some of the observed light curves arepresented.

The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJS...99..135A&db_key=AST

Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.

Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.

Speckle observations of visual and spectroscopic binaries. V.
Not Available

Corrections to the right ascension to be applied to the apparent places of 1217 stars given in "The Chinese Astronomical Almanach" for the year 1984 to 1992.
Not Available

Speckle observations of visual and spectroscopic binaries. III
This is the third paper of this series giving results of speckleobservations carried out for seven visual and 119 spectroscopic binariesat seven nights from May 20 to May 27, 1989, and for 30 visual and 272spectroscopic binaries at 12 nights from June 11 to June 15, and fromAugust 28 to September 3, 1990, using the 212-cm telescope at San PedroMartir Observatory in Mexico. Fringes in the lower spectrum of 31 visualand spectroscopic binaries with angular separation larger than 21 arcsecare obtained. Additionally to two spectroscopic binaries, HD41116 andHD206901, named in the second paper of this series, six spectroscopicbinaries are found each of which has the third component starsurrounding two stars of spectroscopic binary having periodic variationof radial velocity.

The Totality in a Primary Minimum of RZ Cassiopeiae
Not Available

Physical data of the fundamental stars.
Not Available

Close binaries observed polarimetrically
Not Available

Miscellaneous spectroscopic notes
Results of slit-spectrograph observations are reported for approximately260 stars. The data presented range from recognition of many new Ap, Am,and other unusual stars to H-alpha observations of early-typesupergiants and Be stars. The material discussed was obtained over thepast 40 years at a number of U.S. observatories and at the DominionAstrophysical Observatory in Victoria, B.C.

A Total Eclipse in RZ Cassiopeiae?
Not Available

Metallicism among A and F giant stars
132 stars considered as A and F giants have been studied for theirproperties in the Geneva photometric system. It is shown that thissystem to derive the temperature, absolute magnitude and Fe/H value forstars in this part of the HR diagram. 36 percent of the stars of oursample exhibit an enhanced value Delta m2 that can be interpreted interms of Fe/H. The red limit of stars having an enhanced Fe/H value is0.225 in B2-V1 or 6500 K in Teff. This corresponds to the limit definedby Vauclair and Vauclair (1982) where the diffusion timescale is equalto the stellar lifetime and permits the assumption that the diffusion isthe process responsible for the metallicism observed in the A and Fgiants.

Meridian observations made with the Carlsberg Automatic Meridian Circle at Brorfelde (Copenhagen University Observatory) 1981-1982
The 7-inch transit circle instrument with which the present position andmagnitude catalog for 1577 stars with visual magnitudes greater than11.0 was obtained had been equipped with a photoelectric moving slitmicrometer and a minicomputer to control the entire observationalprocess. Positions are reduced relative to the FK4 system for each nightover the whole meridian rather than the usual narrow zones. Thepositions of the FK4 stars used in the least squares solution are alsogiven in the catalog.

An investigation of radius anomalies among short-period Cepheids
Simultaneous photometric and spectroscopic observations have beenobtained of two short-period Cepheids, SU Cas and TU Cas. The Wesselinkmethod of Barnes et al. was used to obtain radii. The radii are found toagree, within the expected error, with evolutionary values. Thisstrengthens the argument that the beat Cepheids are normal Cepheids inmixed-mode behavior rather than a separate class of objects and thatevolutionary masses and radii are correct.

A comparison of the orbital inclinations of the spatially close spectroscopic double stars
The reported investigation takes into account 888 spectroscopicbinaries. It was possible to obtain 120 groups whose elements arespatially close according to the given definition. These 120 groupscontain 313 spectroscopic binaries. 136 of these binaries are 2-spectrumsystems, 177 are 1-spectrum systems, and 62 are eclipsing binaries. Thenumber of systems with known luminosity class is 54. The spectraldistribution of the 313 systems is discussed. The orbital inclinationsand other parameters are presented in a table.

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Observation and Astrometry data

Right ascension:02h44m49.70s
Apparent magnitude:5.95
Distance:124.688 parsecs
Proper motion RA:17.4
Proper motion Dec:-32.8
B-T magnitude:6.094
V-T magnitude:5.961

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 16769
TYCHO-2 2000TYC 4312-1404-1
USNO-A2.0USNO-A2 1575-01486060
BSC 1991HR 791
HIPHIP 12821

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