Contingut
Imatges
Carregar la teva Imatge
DSS Images Other Images
Articles Relacionats
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
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| 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
| 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.
| Photometry of Stars in the Field of V345 and V553 Aquilae
Not Available
| Photometry of Stars in the Field of AV Cygni and DV Cygni
Not Available
| Preliminary UVBY calibrations for G and K type dwarf stars
Four-color uvby photometry for several hundred late-type dwarf stars oftypes G, K and M is discussed. Mean values of photometric indices aregiven for MK spectral types between F8/G0V and M2V. Preliminary standardrelations between the four-color indices are derived. Based onparallaxes and results from high-dispersion spectroscopic analyses,calibrations of the observed indices in terms of Mv, log Te and Fe/Hhave been derived. The means errors are 0.29 mag, 0.009 dex, and 0.17dex, respectively. The calibrations are valid for class-V stars of allpopulations between G0 and M2. If extreme population-II dwarfs areexcluded, the mean error of the abundance calibration decreases to 0.13dex. Calibrations in terms of log g have been attempted,, but the lowaccuracy of the spectroscopic g determinations does not inspireconfidence in the results. The possible contribution of a'fourth-parameter' variation to the mean errors of the calibrations isbriefly discussed. This fourth parameter could be the intrinsic heliumabundance of the stars.
| A sample of old-disk-population red giants.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976PASP...88..426E&db_key=AST
|
Enviar un nou article
Enllaços Relacionats
- - No s'ha trobat enllaços -
Enviar un nou enllaç
Membre dels grups següents:
|
Dades d'Observació i Astrometria
| Constel·lació: | Virgo |
| Ascensió Recta: | 14h24m35.84s |
| Declinació: | -02°20'34.3" |
| Magnitud Aparent: | 7.218 |
| Distancia: | 284.091 parsecs |
| Moviment propi RA: | -29.7 |
| Moviment propi Dec: | 4.9 |
| B-T magnitude: | 9.305 |
| V-T magnitude: | 7.391 |
Catàlegs i designacions:
|
