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Публикации по объекту
3.6 Years of DIRBE Near-infrared Stellar Light Curves
The weekly averaged near-infrared fluxes for 2652 stars were extractedfrom the cold and warm era all-sky maps of the Diffuse InfraredBackground Experiment (DIRBE). Since the DIRBE program only archived theindividual Calibrated Infrared Observations for the 10 month cold eramission, the weekly averaged fluxes were all that were available for thewarm era. The steps required to extract stellar fluxes are described asare the adjustments that were necessary to correct the results forseveral systematic effects. The observations are at a cadence of once aweek for 3.6 years (~1300 days), providing continuous sampling onvariable stars that span the entire period for the longest fundamentalpulsators. The stars are divided into three categories: those with largeamplitude of variability, smaller amplitude variables, and sources whosenear-infrared brightness do not vary according to our classificationcriteria. We show examples of the results and the value of the addedbaseline in determining the phase lag between the visible and infrared.
| Spectroscopic binaries among Hipparcos M giants^,. I. Data, orbits, and intrinsic variations
Context: This paper is a follow-up on the vast effort to collect radialvelocity data for stars belonging to the Hipparcos survey. Aims: We aimat extending the orbital data available for binaries with M giantprimaries. The data presented in this paper will be used in thecompanion papers of this series to (i) derive the binary frequency amongM giants and compare it to that of K giants (Paper II); and (ii) analysethe eccentricity - period diagram and the mass-function distribution(Paper III). Methods: Keplerian solutions are fitted to radial-velocitydata. However, for several stars, no satisfactory solution could befound, even though the radial-velocity standard deviation is greaterthan the instrumental error, because M giants suffer from intrinsicradial-velocity variations due to pulsations. We show that theseintrinsic radial-velocity variations can be linked with both the averagespectral-line width and the photometric variability. Results: Wepresent an extensive collection of spectroscopic orbits for M giantswith 12 new orbits, plus 17 from the literature. On top of these, 1preliminary orbit yielded an approximate value for the eccentricity andthe orbital period. Moreover, to illustrate how the largeradial-velocity jitter present in Mira and semi-regular variables mayeasily be confused with orbital variations, we also present examples ofpseudo-orbital variations (in S UMa, X Cnc, and possibly in HD 115 521,a former IAU radial-velocity standard). Because of this difficulty, Mgiants involving Mira variables were excluded from our monitored sample.We finally show that the majority of M giants detected as X-ray sourcesare actually binaries. Conclusions: The data presented in this paperconsiderably increase the orbital data set for M giants, and will allowus to conduct a detailed analysis of the eccentricity - period diagramin a companion paper (Paper III).Based on observations carried out at the Swiss telescope installed atthe Observatoire de Haute Provence (OHP, France), and at the 1.93-m OHPtelescope. Full Tables 2, 3, and Table 6 are only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/498/627
| Spectroscopic binaries among Hipparcos M giants. II. Binary frequency
Context: This paper is the second in a series devoted to studying theproperties of binaries with M giant primaries. Aims: The binaryfrequency of field M giants is derived and compared with the binaryfraction of K giants. Methods: Diagrams of the CORAVELspectroscopic parameter Sb (measuring the average line width) vs.radial-velocity standard deviation for our samples were used to defineappropriate binarity criteria. These then served to extract the binarityfraction among the M giants. Comparison is made to earlier data on Kgiant binarity frequency. The Sb parameter is discussed in relation toglobal stellar parameters, and the Sb vs. stellar radius relation isused to identify fast rotators. Results: We find that thespectroscopic binary detection rate among field M giants, in a samplewith few velocity measurements (~2), unbiased toward earlier knownbinaries, is 6.3%. This is less than half of the analogous rate forfield K giants. This difference originates in the greater difficulty offinding binaries among M giants because of their smaller orbitalvelocity amplitudes and larger intrinsic jitter and in the differentdistributions of K and M giants in the eccentricity-period diagram. Ahigher detection rate was obtained in a smaller M giant sample with moreradial velocity measurements per object: 11.1% confirmed plus 2.7%possible binaries. The CORAVEL spectroscopic parameter Sb was found tocorrelate better with the stellar radius than with either luminosity oreffective temperature separately. Two outliers of the Sb vs. stellarradius relation, HD 190658 and HD 219654, have been recognised as fastrotators. The rotation is companion-induced, as both objects turn out tobe spectroscopic binaries.Based on observations carried out at the Swiss telescope installed atthe Observatoire de Haute Provence (OHP, France), and at the 1.93-m OHPtelescope.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
The availability of the Hipparcos Catalogue has triggered many kinematicand dynamical studies of the solar neighbourhood. Nevertheless, thosestudies generally lacked the third component of the space velocities,i.e., the radial velocities. This work presents the kinematic analysisof 5952 K and 739 M giants in the solar neighbourhood which includes forthe first time radial velocity data from a large survey performed withthe CORAVEL spectrovelocimeter. It also uses proper motions from theTycho-2 catalogue, which are expected to be more accurate than theHipparcos ones. An important by-product of this study is the observedfraction of only 5.7% of spectroscopic binaries among M giants ascompared to 13.7% for K giants. After excluding the binaries for whichno center-of-mass velocity could be estimated, 5311 K and 719 M giantsremain in the final sample. The UV-plane constructed from these datafor the stars with precise parallaxes (σπ/π≤20%) reveals a rich small-scale structure, with several clumpscorresponding to the Hercules stream, the Sirius moving group, and theHyades and Pleiades superclusters. A maximum-likelihood method, based ona Bayesian approach, has been applied to the data, in order to make fulluse of all the available stars (not only those with precise parallaxes)and to derive the kinematic properties of these subgroups. Isochrones inthe Hertzsprung-Russell diagram reveal a very wide range of ages forstars belonging to these groups. These groups are most probably relatedto the dynamical perturbation by transient spiral waves (as recentlymodelled by De Simone et al. \cite{Simone2004}) rather than to clusterremnants. A possible explanation for the presence of younggroup/clusters in the same area of the UV-plane is that they have beenput there by the spiral wave associated with their formation, while thekinematics of the older stars of our sample has also been disturbed bythe same wave. The emerging picture is thus one of dynamical streamspervading the solar neighbourhood and travelling in the Galaxy withsimilar space velocities. The term dynamical stream is more appropriatethan the traditional term supercluster since it involves stars ofdifferent ages, not born at the same place nor at the same time. Theposition of those streams in the UV-plane is responsible for the vertexdeviation of 16.2o ± 5.6o for the wholesample. Our study suggests that the vertex deviation for youngerpopulations could have the same dynamical origin. The underlyingvelocity ellipsoid, extracted by the maximum-likelihood method afterremoval of the streams, is not centered on the value commonly acceptedfor the radial antisolar motion: it is centered on < U > =-2.78±1.07 km s-1. However, the full data set(including the various streams) does yield the usual value for theradial solar motion, when properly accounting for the biases inherent tothis kind of analysis (namely, < U > = -10.25±0.15 kms-1). This discrepancy clearly raises the essential questionof how to derive the solar motion in the presence of dynamicalperturbations altering the kinematics of the solar neighbourhood: doesthere exist in the solar neighbourhood a subset of stars having no netradial motion which can be used as a reference against which to measurethe solar motion?Based on observations performed at the Swiss 1m-telescope at OHP,France, and on data from the ESA Hipparcos astrometry satellite.Full Table \ref{taba1} is only available in electronic form at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/430/165}
| Hipparcos red stars in the HpV_T2 and V I_C systems
For Hipparcos M, S, and C spectral type stars, we provide calibratedinstantaneous (epoch) Cousins V - I color indices using newly derivedHpV_T2 photometry. Three new sets of ground-based Cousins V I data havebeen obtained for more than 170 carbon and red M giants. These datasetsin combination with the published sources of V I photometry served toobtain the calibration curves linking Hipparcos/Tycho Hp-V_T2 with theCousins V - I index. In total, 321 carbon stars and 4464 M- and S-typestars have new V - I indices. The standard error of the mean V - I isabout 0.1 mag or better down to Hp~9 although it deteriorates rapidly atfainter magnitudes. These V - I indices can be used to verify thepublished Hipparcos V - I color indices. Thus, we have identified ahandful of new cases where, instead of the real target, a random fieldstar has been observed. A considerable fraction of the DMSA/C and DMSA/Vsolutions for red stars appear not to be warranted. Most likely suchspurious solutions may originate from usage of a heavily biased color inthe astrometric processing.Based on observations from the Hipparcos astrometric satellite operatedby the European Space Agency (ESA 1997).}\fnmsep\thanks{Table 7 is onlyavailable 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/qcat?J/A+A/397/997
| Long period variable stars: galactic populations and infrared luminosity calibrations
In this paper HIPPARCOS astrometric and kinematic data are used tocalibrate both infrared luminosities and kinematical parameters of LongPeriod Variable stars (LPVs). Individual absolute K and IRAS 12 and 25luminosities of 800 LPVs are determined and made available in electronicform. The estimated mean kinematics is analyzed in terms of galacticpopulations. LPVs are found to belong to galactic populations rangingfrom the thin disk to the extended disk. An age range and a lower limitof the initial mass is given for stars of each population. A differenceof 1.3 mag in K for the upper limit of the Asymptotic Giant Branch isfound between the disk and old disk galactic populations, confirming itsdependence on the mass in the main sequence. LPVs with a thin envelopeare distinguished using the estimated mean IRAS luminosities. The levelof attraction (in the classification sense) of each group for the usualclassifying parameters of LPVs (variability and spectral types) isexamined. Table 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/374/968 or via ASTRIDdatabase (http://astrid.graal.univ-montp2.fr).
| Aufsuchkarten fur intrinsic Variable Stars in Brno.
Not Available
| Beobachtungsergebnisse Bundesdeutsche Arbeitsgemeinschaft fur Veraenderliche Sterne e.V.
Not Available
| Stars with the Largest Hipparcos Photometric Amplitudes
A list of the 2027 stars that have the largest photometric amplitudes inHipparcos Photometry shows that most variable stars are all Miras. Thepercentage of variable types change as a function of amplitude. Thiscompilation should also be of value to photometrists looking forrelatively unstudied, but large amplitude stars.
| Period-Luminosity-Colour distribution and classification of Galactic oxygen-rich LPVs. I. Luminosity calibrations
The absolute K magnitudes and kinematic parameters of about 350oxygen-rich Long-Period Variable stars are calibrated, by means of anup-to-date maximum-likelihood method, using Hipparcos parallaxes andproper motions together with radial velocities and, as additional data,periods and V-K colour indices. Four groups, differing by theirkinematics and mean magnitudes, are found. For each of them, we alsoobtain the distributions of magnitude, period and de-reddened colour ofthe base population, as well as de-biased period-luminosity-colourrelations and their two-dimensional projections. The SRa semiregulars donot seem to constitute a separate class of LPVs. The SRb appear tobelong to two populations of different ages. In a PL diagram, theyconstitute two evolutionary sequences towards the Mira stage. The Mirasof the disk appear to pulsate on a lower-order mode. The slopes of theirde-biased PL and PC relations are found to be very different from theones of the Oxygen Miras of the LMC. This suggests that a significantnumber of so-called Miras of the LMC are misclassified. This alsosuggests that the Miras of the LMC do not constitute a homogeneousgroup, but include a significant proportion of metal-deficient stars,suggesting a relatively smooth star formation history. As a consequence,one may not trivially transpose the LMC period-luminosity relation fromone galaxy to the other Based on data from the Hipparcos astrometrysatellite. Appendix B is only 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
| Multiperiodicity in semiregular variables. I. General properties
We present a detailed period analysis for 93 red semiregular variablesby means of Fourier and wavelet analyses of long-term visualobservations carried out by amateur astronomers. The results of thisanalysis yield insights into the mode structure of semiregular variablesand help to clarify the relationship between them and Mira variables.After collecting all available data from various international databases(AFOEV, VSOLJ, HAA/VSS and AAVSO) we test the accuracy and reliabilityof data. We compare the averaged and noise-filtered visual light curveswith simultaneous photoelectric V-measurements, the effect of the lengthversus the relatively low signal-to-noise ratio is illustrated by periodanalysis of artificial data, while binning effects are tested bycomparing results of frequency analyses of the unbinned and averagedlight curves. The overwhelming majority of the stars studied showmultiperiodic behaviour. We found two significant periods in 44variables, while there are definite signs of three periods in 12 stars.29 stars turned out to be monoperiodic with small instabilities in theperiod. Since this study deals with the general trends, we wanted tofind only the most dominant periods. The distribution of periods andperiod ratios is examined through the use of the (log P_0, log P_1) and(log P_1, log P_0/P_1) plots. Three significant and two less obvioussequences are present which could be explained as the direct consequenceof different pulsational modes. This hypothesis is supported by theresults for multiperiodic variables with three periods. Finally, thesespace methods are illustrated by several interesting case studies thatshow the best examples of different special phenomena such as long-termamplitude modulation, amplitude decrease and mode switching.
| Classification and Identification of IRAS Sources with Low-Resolution Spectra
IRAS low-resolution spectra were extracted for 11,224 IRAS sources.These spectra were classified into astrophysical classes, based on thepresence of emission and absorption features and on the shape of thecontinuum. Counterparts of these IRAS sources in existing optical andinfrared catalogs are identified, and their optical spectral types arelisted if they are known. The correlations between thephotospheric/optical and circumstellar/infrared classification arediscussed.
| 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.
| A different type of maser star
A systematic survey of short-period, semiregular variable stars has beenmade resulting in the detection of six new water masers. Of the 14short-period maser stars now known, nine are classified as SRbvariables. All are very late spectral type SRb's, typically M7, whilethe overwhelming majority of normal SRb stars is M4 to M6. Their 2.2-11micron color indices are among the lowest of any known maser stars. Theyare presumably less dusty as well. Four of the SRb stars and two of theremainder do not obey the correlation between period and velocity spreadof the emission features that is found for the Mira and long-period,semiregular variables. Finally, high galactic latitudes dominate; 13 ofthe 14 are in excess of 13 deg, and nine of these are greater than 25deg. These facts suggest that the short-period semiregular variables -particularly in SRb stars - may be a very different type of maser starthan the Mira and long-period semiregular variables.
| The kinematics of semiregular red variables in the solar neighbourhood.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972MNRAS.158...23F&db_key=AST
| Classification of Late M-Type Stars from Low-Dispersion Spectra in the Near Infrared.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJ...122..177C&db_key=AST
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Наблюдательные данные и астрометрия
| Созвездие: | Жираф |
| Прямое восхождение: | 05h35m27.17s |
| Склонение: | +72°27'57.6" |
| Видимая звёздная величина: | 10.311 |
| Собственное движение RA: | 0.9 |
| Собственное движение Dec: | 4.6 |
| B-T magnitude: | 12.199 |
| V-T magnitude: | 10.467 |
Каталоги и обозначения:
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