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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.
| 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.
| Accurate Positions Of Suspected Variable Stars Near The South Galactic Pole
Not Available
| Mass-losing stars in the South Galactic CAP
Observations are presented for 162 late-type stars in the South GalacticCap (b<-30 deg) which were selected on the basisof their IRAS 25/12-μm flux ratios as high-mass-loss candidates. JHKLphotometry (over 1100 observations) was obtained for all of the stars,BV(RI)_C photometry for 78 of them and optical spectra for 51. 154 ofthese stars are non-Mira M or S stars, of which many, and possibly all,are semi-regular variables. Of the remaining eight IRAS objects, threeare T Tauri stars, three are interacting binaries and two are carbonstars. A few of the M giants and both of the carbon stars havecircumstellar envelopes of the type more normally associated with Miravariables. These include two 1612-MHz OH maser sources. It is suggestedthat such stars may have been Miras in the recent past, but arecurrently out of the instability strip owing to a recently experiencedhelium-shell flash. Alternatively, some of them could be binary stars,but there is as yet no evidence for the second star. The near-infraredcolours of the M giants are compared with those of similar stars in theBulge. They are similar to those of the inner Bulge and unlike thosefound in either the outer Bulge or the globular clusters. The kinematicsand Galactic distribution of the M giants indicate that they areprobably from a mixed population and that they could be associated withMiras with a range of periods. A comparison of the observed colours withthose derived from models indicates a range of metallicity with the bulkof stars slightly more metal-rich than the Sun. It also revealssignificant numbers of stars with colours outside the predicted range,possible due to the effects of circumstellar reddening or toinadequacies in the models. The most metal-rich examples of the M starshave high mass-loss rates for non-Miras (~10^-6 M_solar yr^-1) and thereare far fewer of them outside than inside the solar circle. This may bedue to a metallicity gradient. These stars have a scaleheight of morethan 500 pc. The two carbon stars have unusual colours and detachedshells. One of them, R Scl, is shown to vary with a period of 379dsuperimposed on a possible second period of about 2300d. The othercarbon star, which is more distant and previously unknown, may also havedouble-period variations.
| 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 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.
| Classification of 831 two-micron sky survey sources south of +5 degrees.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975AJ.....80.1011H&db_key=AST
| Bright Southern BV-Stars
Not Available
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | לויתן |
| התרוממות ימנית: | 01h50m33.96s |
| סירוב: | -17°39'00.4" |
| גודל גלוי: | 10.5 |
| תנועה נכונה: | -6.7 |
| תנועה נכונה: | -17.2 |
| B-T magnitude: | 12.15 |
| V-T magnitude: | 10.637 |
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