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 A Physical Orbit for the High Proper Motion Binary HD 9939We report spectroscopic and interferometric observations of the highproper motion double-lined binary system HD 9939, with an orbital periodof approximately 25 days. By combining our radial-velocity andvisibility measurements, we estimate the system physical orbit andderive dynamical masses for the components ofMA=1.072+/-0.014 Msolar andMB=0.8383+/-0.0081 Msolar, with fractional errorsof 1.3% and 1.0%, respectively. We also determine a system distance of42.23+/-0.21 pc, corresponding to an orbital parallax ofπorb=23.68+/-0.12 mas. The system distance and theestimated brightness difference between the stars in V, H, and K yieldcomponent absolute magnitudes in these bands. By spectroscopic analysisand spectral energy distribution modeling, we also estimate thecomponent effective temperatures and luminosities asTAeff=5050+/-100 K andTBeff=4950+/-200 K and LA=2.451+/-0.041Lsolar and LB=0.424+/-0.023 Lsolar.Both our spectral analysis and comparison with stellar models suggestthat HD 9939 has elemental abundances near solar values. Further,comparison with stellar models suggests that the HD 9939 primary hasevolved off the main sequence and appears to be traversing theHertzsprung gap as it approaches the red giant phase of its evolution.Our measurements of the primary properties provide new empiricalconstraints on stellar models during this particularly dynamicevolutionary phase. That HD 9939 is currently in a relatively shortlived evolutionary state allows us to estimate the system age as9.12+/-0.25 Gyr. In turn, the age and abundance of the system place apotentially interesting, if anecdotal, constraint on star formation inthe Galactic disk. Metallicity Determinations from Ultraviolet-Visual Spectrophotometry. I. The Test SampleNew visual spectrophotometric observations of non-supergiant solarneighborhood stars are combined with IUE Newly Extracted Spectra (INES)energy distributions in order to derive their overall metallicities,[M/H]. This fundamental parameter, together with effective temperatureand apparent angular diameter, is obtained by applying the flux-fittingmethod while surface gravity is derived from the comparison withevolutionary tracks in the theoretical H-R diagram. Trigonometricparallaxes for the stars of the sample are taken from the HipparcosCatalogue. The quality of the flux calibration is discussed by analyzinga test sample via comparison with external photometry. The validity ofthe method in providing accurate metallicities is tested on a selectedsample of G-type stars with well-determined atmospheric parameters fromrecent high-resolution spectral analysis. The extension of the overallprocedure to the determination of the chemical composition of all theINES non-supergiant G-type stars with accurate parallaxes is planned inorder to investigate their atmospheric temperature structure. Based onobservations collected at the INAOE G. Haro'' Observatory, Cananea(Mexico). Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin iThis 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 Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statisticsThe Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521 Research Note Hipparcos photometry: The least variable starsThe data known as the Hipparcos Photometry obtained with the Hipparcossatellite have been investigated to find those stars which are leastvariable. Such stars are excellent candidates to serve as standards forphotometric systems. Their spectral types suggest in which parts of theHR diagrams stars are most constant. In some cases these values stronglyindicate that previous ground based studies claiming photometricvariability are incorrect or that the level of stellar activity haschanged. Table 2 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/367/297 The proper motions of fundamental stars. I. 1535 stars from the Basic FK5A 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 (130.79.128.5) or viahttp://cdsweb.u-strastg.fr/cgi-bin/qcat?J/A+A/365/222 Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutionsThe FK6 is a suitable combination of the results of the HIPPARCOSastrometry satellite with ground-based data, measured over more than twocenturies and summarized in the FK5. Part I of the FK6 (abbreviatedFK6(I)) contains 878 basic fundamental stars with direct solutions. Suchdirect solutions are appropriate for single stars or for objects whichcan be treated like single stars. From the 878 stars in Part I, we haveselected 340 objects as "astrometrically excellent stars", since theirinstantaneous proper motions and mean (time-averaged) ones do not differsignificantly. Hence most of the astrometrically excellent stars arewell-behaving "single-star candidates" with good astrometric data. Thesestars are most suited for high-precision astrometry. On the other hand,199 of the stars in Part I are Δμ binaries in the sense ofWielen et al. (1999). Many of them are newly discovered probablebinaries with no other hitherto known indication of binarity. The FK6gives, besides the classical "single-star mode" solutions (SI mode),other solutions which take into account the fact that hidden astrometricbinaries among "apparently single-stars" introduce sizable "cosmicerrors" into the quasi-instantaneously measured HIPPARCOS proper motionsand positions. The FK6 gives in addition to the SI mode the "long-termprediction (LTP) mode" and the "short-term prediction (STP) mode". TheseLTP and STP modes are on average the most precise solutions forapparently single stars, depending on the epoch difference with respectto the HIPPARCOS epoch of about 1991. The typical mean error of anFK6(I) proper motion in the single-star mode is 0.35 mas/year. This isabout a factor of two better than the typical HIPPARCOS errors for thesestars of 0.67 mas/year. In the long-term prediction mode, in whichcosmic errors are taken into account, the FK6(I) proper motions have atypical mean error of 0.50 mas/year, which is by a factor of more than 4better than the corresponding error for the HIPPARCOS values of 2.21mas/year (cosmic errors included). The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circleThe 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. Intrinsic Energy Distribution in Stellar Spectra in the Wavelength Interval 320--760 NMThe intrinsic energy distributions in the interval 320--760 nm ofspectral types B5--G8 of luminosity V, F0--F5 of luminosity IV andG8--M2 of luminosity III, determined by authors, are intercompared withthe catalogue of the mean energy distribution data published bySviderskiene (1988). The Relation between Rotational Velocities and Spectral Peculiarities among A-Type StarsAbstract 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. SANTIAGO 91, a right ascension catalogue of 3387 stars (equinox J2000).The positions in right ascension of 3387 stars belonging to the Santiago67 Catalogue, observed with the Repsold Meridian Circle at Cerro Calan,National Astronomical Observatory, during the period 1989 to 1994, aregiven. The average mean square error of a position, for the wholeCatalogue, is +/-0.009 s. The mean epoch of the catalogue is 1991.84. The second Quito astrolabe catalogueThe paper contains 515 individual corrections {DELTA}α and 235corrections {DELTA}δ to FK5 and FK5Supp. stars and 50 correctionsto their proper motions computed from observations made with theclassical Danjon astrolabe OPL-13 at Quito Astronomical Observatory ofEcuador National Polytechnical School during a period from 1964 to 1983.These corrections cover the declination zone from -30deg to +30deg. Meanprobable errors of catalogue positions are 0.047" in αcosδand 0.054" in δ. The systematic trends of the catalogue{DELTA}αalpha_cosδ,{DELTA}αdelta_cosδ,{DELTA}δalpha_, {DELTA}δdelta_ arepresented for the observed zone. Model atmospheres - Tool for identifying interstellar featuresModel atmosphere parameters are derived for 14 early A stars withrotation velocities, from optical spectra, in excess of 80 km/s. Themodels are compared with IUE observations of the stars in regions whereinterstellar lines are expected. In general, with the assumption ofsolar abundances, excellent fits are obtained in regions longward of2580 A, and accurate interstellar equivalent widths can be derived usingmodels to establish the continuum. The fits are poorer at shorterwavelengths, particularly at 2026-2062 A, where the stellar modelparameters seem inadequate. Features indicating mass flows are evidentin stars with known infrared excesses. In gamma TrA, variability in theMg II lines is seen over the 5-year interval of these data, and alsoover timescales as short as 26 days. The present technique should beuseful in systematic studies of episodic mass flows in A stars and forstellar abundance studies, as well as interstellar features. 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 Secondary spectrophotometric standards - Mean energy distribution in the spectra of A starsForty-nine A stars of IV and V luminosity classes are used to obtainmean spectral energy distributions of stars of different subtypes.Forty-six are in the catalog of 238 secondary spectrophotometricstandards, which are characterized by good agreement between thespectrophotometric data of the Moscow and Alma-Ata catalogs. Three starsare primary standards. Mean energy distributions for all the subtypes ofthe A type in the range 3200-7600 A are presented. The effectivetemperatures obtained from a comparison with the theoretical modelatmospheres of Kurucz (1979) are in satisfactory agreement with theT(eff) scale constructed on the basis of total flux determinations. Santiago Fundamental Catalogue - A catalogue of 1105 FK5 stars (equinox J2000.0)The positions in right ascension and declination of 1105 FK5 stars,observed with a Meridian Circle during the period 1979 to 1991, aregiven. The average mean square error of a position, for the wholecatalog, is +/- 0.009 s in right ascension and +/- 0.10 arcsec indeclination. The mean epoch of the catalog is 1983.148. Secondary spectrophotometric standardsEnergy distribution data on 238 secondary standard stars are presentedin the range 3200-7600 A with 50 A step. These stars are common to theCatalog of the Sternberg State Astronomical Institute and the FessenkovAstrophysical Institute. For these stars, the differences betweenspectral energy distribution data of the two catalogs do not exceed 5percent, while the mean internal accuracy of both catalogs data in thisrange are about 3.5 percent. For 99 stars energy distribution data inthe near infrared (6000-10,800 A) obtained at the Sternberg StateAstronomical Institute are also presented. The correction in right ascension of 508 stars determinated with PMO photoelectric transit instrument.Not Available Santiago declination catalogue. II - A declination catalogue of 493 FK5 stars (equinox J2000.0)Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1991A&AS...90..109C&db_key=AST Physical data of the fundamental stars.Not Available Ionization in nearby interstellar gasDue to dielectric recombination, neutral magnesium represents animportant tracer for the warm low-density gas around the solar system.New Mg I 2852 absorption-line data from IUE are presented, includingdetections in a few stars within 40 pc of the sun. The absence ofdetectable Mg I in Alpha CMa and other stars sets limits on the combinedsize and electron density of the interstellar cloud which gives rise tothe local interstellar wind. For a cloud radius greater than 1 pc anddensity of 0.1/cu cm, the local cloud has a low fractional ionization,n(e)/n(tot) less than 0.05, if magnesium is undepleted, equilibriumconditions prevail, the cloud temperature is 11,750 K, and 80 percent ofthe magnesium in the sightline is Mg II. Stellar integrated fluxes in the wavelength range 380 NM - 900 NM derived from Johnson 13-colour photometryPetford et al. (1988) have reported measured integrated fluxes for 216stars with a wide spread of spectral type and luminosity, and mentionedthat a cubic-spline integration over the relevant Johnson 13-colormagnitudes, converted to fluxes using Johnson's calibration, is inexcellent agreement with those measurements. In this paper a list of thefluxes derived in this way, corrected for a small dependence on B-V, isgiven for all the 1215 stars in Johnson's 1975 catalog with completeentries. A catalogue of right ascensions and declinations of FK4 starsThe position parameters of 578 stars from the fundamental catalog FK4are determined on the basis of 3-4-h meridian-circle observationsobtained by the differential method at Belgrade Astronomical Observatoryduring 1981-1987. The observation method and data-reduction proceduresare explained, and the results are compiled in extensive tables. Theaverage mean-square errors per observation are found to beepsilon(alpha) cos delta = + or - 0.022 sec and epsilon(delta) = + or -0.32 arcsec. Two catalogues of FK4 right-ascension corrections and their applicationThe results of observations conducted as part of the regular timeservice with transit instruments at the Borowiec and BratislavaObservatories were used to work out catalogs of right-ascensioncorrections of the FK4 stars, included in the observational programs.The characteristics of both catalogs are presented in the paper.Comparisons between the catalogs as well as their comparison with thecompilation catalog produced on the basis of observations performed withastrolabes are given. The results of applying these right-ascensioncorrections to the re-reduction of universal time are also presented. The early A type stars - Refined MK classification, confrontation with Stroemgren photometry, and the effects of rotationThe MK classification system for the early A-type stars is refined, anda parallel system of standards for the broad-lined stars is introduced.With this improved system, stars may be classified with significantlygreater precision than before. It is shown that spectral types in thissystem are not systematically affected by rotational line broadening. Atotal of 372 early A-type stars are classified, and a confrontation ofthese spectral types with Stroemgren photometry reveals a number ofsystematic photometric effects of rotation. In particular, high v sin istars are systematically redder than low v sin i stars of the samespectral type, and the beta index is weakened by rotation. It isconcluded that precise spectral classification in conjunction withStroemgren and H-beta photometry can potentially provide a valuablecheck and input to the theory of the atmospheres of rotating stars. Limits on the local fluff from IUE MG I dataThe known properties of the local interstellar medium (local fluff) arecombined with IUE observations of the 2852 A line of Mg I 0.003/cc. Ifno other cloud is present, the geometry of the fluff in the direction ofa background target star showing an equivalent width, W(mA), for the MgI 2852 A line can be estimated from the relation W(2852 A)/L less thanor = ne X 350, where L (pc) is the cloud extent and ne(percc) theelectron density in the cloud. A new photometric WBVR systemA description of the new broad-band photometric system, WBVR, is given.It is shown that WBVR is close to the UBVR system but is defined bystrictly fixed response curves and the primary standard. Theconstruction of a network of secondary standards distributed uniformlyin the northern sky, as well as the coordination of the magnitudes ofthe standards to the self-consistent system are discussed. All standardsare examined for a possible brightness variability and it is found thatno light variability exceeding 0.015 mag in amplitude is present andthat their average magnitude shows stability on a scale of severalyears. The individual WBVR observations of the standards are presentedin tables. Catalogue of the energy distribution data in spectra of stars in the uniform spectrophotometric system.Not Available
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