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VSOP: the variable star one-shot project. I. Project presentation and first data release
Context: About 500 new variable stars enter the General Catalogue ofVariable Stars (GCVS) every year. Most of them however lackspectroscopic observations, which remains critical for a correctassignement of the variability type and for the understanding of theobject. Aims: The Variable Star One-shot Project (VSOP) is aimed at (1)providing the variability type and spectral type of all unstudiedvariable stars, (2) process, publish, and make the data available asautomatically as possible, and (3) generate serendipitous discoveries.This first paper describes the project itself, the acquisition of thedata, the dataflow, the spectroscopic analysis and the on-lineavailability of the fully calibrated and reduced data. We also presentthe results on the 221 stars observed during the first semester of theproject. Methods: We used the high-resolution echelle spectrographsHARPS and FEROS in the ESO La Silla Observatory (Chile) to survey knownvariable stars. Once reduced by the dedicated pipelines, the radialvelocities are determined from cross correlation with synthetic templatespectra, and the spectral types are determined by an automatic minimumdistance matching to synthetic spectra, with traditional manual spectraltyping cross-checks. The variability types are determined by manuallyevaluating the available light curves and the spectroscopy. In thefuture, a new automatic classifier, currently being developed by membersof the VSOP team, based on these spectroscopic data and on thephotometric classifier developed for the COROT and Gaia space missions,will be used. Results: We confirm or revise spectral types of 221variable stars from the GCVS. We identify 26 previously unknown multiplesystems, among them several visual binaries with spectroscopic binaryindividual components. We present new individual results for themultiple systems V349 Vel and BCGru, for the composite spectrum star V4385Sgr, for the T Tauri star V1045 Sco, andfor DM Boo which we re-classify as a BY Draconisvariable. The complete data release can be accessed via the VSOP website.Based on data obtained at the La Silla Observatory, European SouthernObservatory, under program ID 077.D-0085.
| 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
| 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.
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| Infrared giants vs. supergiants. II. CO observations
We report systematic observations of millimeter CO emission from asample of 109 oxygen-rich evolved stars (AGB and supergiants),colour-selected from the IRAS Point Source Catalog (0.69 200). In most cases, the observed spread in the valuesof this ratio can be explained by a large range of luminosities. Thisleads to a new criterion to identify AGB stars: an object with {cal R}< 150 must have a low mass progenitor. Here we study the correlationsbetween {cal R} and various physical properties of the sources. Mostsources with high values of {cal R} also have low galactic latitudes,small IRAS variability indices, and early spectral types (typicallyM1-M5). Conversely, there is no dependence on the IRAS colours, nor onthe intensity of silicate 10;microns emission. However, a few AGB starsexhibit large {cal R}; other factors than luminosity are required toexplain these values. Different hypotheses, such as the possiblepresence of a chromosphere, a low (12) C abundance or a variablemass-loss rate, are examined. Considering the global high OH detectionrate ( ~ 67%), we studied the correlations with CO and OH emission. Thedetection of OH seems to be a useful discriminator of mechanisms thatenhance {cal R}.
| 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.
| 86 GHz SiO, v=1, J=2--> 1 survey of southern IRAS point sources. II. Detection of 74 new maser sources
The detection of 74 new southern stellar SiO, v=1, J=2->1 masersassociated with IRAS point sources is reported. 57 of these were foundin an IRAS based survey of oxygen rich stellar envelopes. The detectionrate in this survey was 45%. 17 further new maser sources were detectedduring a search for strong pointing sources for the Swedish-ESOSubmillimeter Telescope (SEST). The distribution of the IRAS lowresolution spectral (LRS) classes of all the SiO masers (this paper andliterature) peaks sharply at class 15. The distribution of the LRSclasses of the maser sources from 21 to 29 is similar to thedistribution of these classes of all the point sources in the pointsource catalogue except for class 25. Only few maser sources of thisspectral class are known. This is possibly explained by a selectioneffect.
| 1612 MHz OH survey of IRAS point sources. I - Observations made at Dwingeloo, Effelsberg and Parkes
The data from a large sky survey are presented including a northernpilot study and a detailed southern study in which detections are biasedtoward the most evolved sources and distant sources. Both areinvestigated at the 1612-MHz transition of OH to take advantage of thestrongest line for AGB stars with optically thick dust shells. The IRASsources are chosen by considering their IR colors related to fluxes at12, 25, and 60 microns. Observations are reported for 2703 IRAS pointsources at the 1612-MHz transition, and 738 OH/IR stars are detected.The survey identifies 597 of the sources as previously unidentified, and95 percent of the OH profiles observed have twin-peak masercharacteristics which are related to emission from expandingcircumstellar shells. The other 5 percent of the sources are concludedto be transition objects between OH/IR stars and planetary nebulae.
| IRAS low-resolution spectral observations of the 10 and 18 micron silicate emission feature
The IRAS LRS Atlas contains 8-23 micron spectra of 1816 stars withsilicate emission features. In order to study the shapes of the silicatedust features, the 117 stars whose emission features appear to beoptically thin and which have the best signal-to-noise ratio at thelongest wavelengths were analyzed. Simple spherical dust shell modelswere calculated in both the optically thin and the slightly opticalthick approximations. From the comparison of the predicted spectra ofthe dust and stellar continuum, the emissivity function Kappa(lambda)was derived. In the different stars, the shape of the 10-micron featureis either narrow or broad and it is peaked either at about 9.7 micronsor at 10 microns. Either particle size effects (particles above 0.75microns in radius) or optical depth effects (central optical depth about1) could broaden the 10-micron feature. Chemical composition differencesno doubt are also important, particularly as regards the position of thepeak of the 10-micron feature. The stars with the peak at 10 microns aremore closely confined to the Galactic plane than the stars with the peakat 9.7 microns. The shape of the 18-micron feature is essentially thesame in all stars, and can be used to extend the interstellar extinctioncurve past 13 to 22 microns.
| Observations of 43-GHz SiO masers associated with bright IRAS sources
A survey of potential SiO maser sources has been made using the Parkesradio telescope operating at 43 GHz. The candidate objects were allbright southern IRAS sources and were selected using criteria developedfor use in an earlier study. A further 29 masers were discovered in thepresent survey and, for most of these sources, data in both v = 1 and v= 2 (J = 1-0) transitions were obtained. Although many of the candidateIRAS sources have not been observed at visual wavelengths, there arepublished optical variability data for nine objects. In these cases therelationship between SiO maser emission and visual amplitude, proposedpreviously, is not violated. It is suggested that, in the main, the newmasers are associated with optically obscured Mira variables. This paperalso presents the latest 43-GHz maser polarization spectra for thenearest symbiotic binary, R Aqr, and for GL 5552, the most intensesource discovered in an earlier survey.
| Water maser emission from southern IRAS sources
A search for water maser emission in 112 bright, southern IRAS sourceswas conducted. Water maser emission was detected in 27 cases. Thesesources include M-type stars and previously unidentified IRAS objects.The detection rate is discussed with reference to IRAS low-resolutionspectral (LRS) class and the (60-25) micron color index. Water maseremission was detected in three sources which have LRS class 4n,indicating the presence of 11-micron SiC emission. The O/C-richness ofthe circumstellar envelopes of these sources is discussed, and it isconcluded that these sources are probably M-type stars whose LRS classis misassigned.
| Valinhos 2.2 micron survey of the southern galactic plane. II - Near-IR photometry, IRAS identifications and nature of the sources
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1987A&AS...71...39E&db_key=AST
| IRAS catalogues and atlases - Atlas of low-resolution spectra
Plots of all 5425 spectra in the IRAS catalogue of low-resolutionspectra are presented. The catalogue contains the average spectra ofmost IRAS poiont sources with 12 micron flux densities above 10 Jy.
| Valinhos 2.2 micron survey of the Southern Galactic plane Positions and infrared photometry of 338 sources
This paper reports on JHKLM photometric measurements of 338 brightinfrared stars found in a 2.2-micron survey of a 10 x 100-deg lane ofthe Southern Galactic plane. More than 2/3 of the objects are notidentified with catalogued stars and are likely to belong-period-variable or reddened giant or supergiant stars.
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| קבוצת-כוכבים: | שדרית |
| התרוממות ימנית: | 11h20m06.23s |
| סירוב: | -65°15'07.1" |
| גודל גלוי: | 8.212 |
| מרחק: | 10000000 פארסק |
| תנועה נכונה: | -5 |
| תנועה נכונה: | 3.1 |
| B-T magnitude: | 11.166 |
| V-T magnitude: | 8.456 |
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