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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
| 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
| Speckle Interferometry of New and Problem HIPPARCOS Binaries
The ESA Hipparcos satellite made measurements of over 12,000 doublestars and discovered 3406 new systems. In addition to these, 4706entries in the Hipparcos Catalogue correspond to double star solutionsthat did not provide the classical parameters of separation and positionangle (rho,theta) but were the so-called problem stars, flagged ``G,''``O,'' ``V,'' or ``X'' (field H59 of the main catalog). An additionalsubset of 6981 entries were treated as single objects but classified byHipparcos as ``suspected nonsingle'' (flag ``S'' in field H61), thusyielding a total of 11,687 ``problem stars.'' Of the many ground-basedtechniques for the study of double stars, probably the one with thegreatest potential for exploration of these new and problem Hipparcosbinaries is speckle interferometry. Results are presented from aninspection of 848 new and problem Hipparcos binaries, using botharchival and new speckle observations obtained with the USNO and CHARAspeckle cameras.
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| Characteristics of OH emission from infrared stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972A&A....17..385W&db_key=AST
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Dades d'Observació i Astrometria
| Constel·lació: | Corvus |
| Ascensió Recta: | 12h52m58.81s |
| Declinació: | -14°37'14.3" |
| Magnitud Aparent: | 7.597 |
| Distancia: | 763.359 parsecs |
| Moviment propi RA: | -28.4 |
| Moviment propi Dec: | -6.8 |
| B-T magnitude: | 9.685 |
| V-T magnitude: | 7.77 |
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