|On the Variability of K5-M Stars|
I investigate the Hipparcos Satellite photometry of K5-M stars to seethe pattern of activity of these stars. A few stars for which furtherstudy is desirable are identified.
|The rotation speed of the companion star in Aquila X-1.|
We have obtained medium resolution spectra of the neutron star X-raytransient Aql X-1 during quiescence. We determine the spectral type ofthe companion star to be K1 and also estimate its rotation speed to be62^+30^_-20_km/s. By measuring the width of the Hα emission lineprofile of the accretion disc, we estimate the binary inclination to~50° and also estimate the semi-amplitude of the companion star'sradial velocity curve to be ~170km/s.
|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.
|Large and kinematically unbiased samples of G- and K-type stars. IV - Evolved stars of the old disk population|
Modified Stromgren and (R,I) photometry, along with DDO and Genevaphotometry, are presented for a complete sample of evolved old-disk Gand K giants in the Bright Star Catalogue. Stars with ages of between1.5 x 10 to the 9th and 10 to the 10th yr are found to have anear-normal distribution of heavy element abundances, centered on anFe/H abundance ratio of -0.1 dex. The old disk clusters NGC 3680 and IC4651 contain red-straggler young-disk giants that are probablycontemporaries of the blue stragglers in the clusters.
|Large and kinematically unbiased samples of G- and K-type stars. II - Observations of evolved stars in the Bright Star sample. III - Evolved young disk stars in the Bright Star sample|
Four color and RI observations were obtained for a large sample ofG-type and K-type stars in the Bright Star Catalogue. Data are firstpresented for 110 evolved stars. Photometry of evolved young diskpopulation stars have then been calibrated for luminosity, reddening,and metallicity on the basis of results for members of the Hyades andSirius superclusters. New DDO results are given for 120 stars.
|The Wolf 630 moving group of stars|
An analysis is made of the probability of collective membership of thestars assigned by Eggen to the Wolf 630 moving group. This probabilityis estimated from the scatter of points in the color-absolute magnitudediagram when compared to the intrinsic scatter observed for M67.Particular attention is paid to the random errors for all the observedand deduced stellar parameters. Results show that either theobservational errors must be about 2.4 times larger than given in theproper motion and radial velocity source catalogues, or the intrinsicscatter in the color-magnitude diagram for the Wolf 630 group must bemuch larger than for M67, or many of the stars considered cannot bemembers.
|Luminosity functions and the evolution of low-mass population I giants|
Luminosity functions in terms of bolometric magnitudes are constructedfor M67 and for two samples of old-disk field giants. These are comparedwith theoretical rates of evolution on the giant branch. M67 has too fewstars to give a useful comparison. The field giants show good agreementwith theory, and the number of stars at the 'clump' suggests that corehelium-burning is prolonged by overshoot with semiconvective mixing. Thefuel consumption derived from the luminosity functions is consistentwith core helium ignition at the theoretically predicted core mass, andwith a final core mass in agreement with observed white dwarf masses.Data are needed for a larger complete sample of field giants for theluminosity function to be better determined. Further details, especiallyfor the variable M giants at the top of the giant branch, are needed forpopulation syntheses of elliptical galaxies.
|Optical polarization of stars of galactic latitudes b-45 degres.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976A&AS...23..125S&db_key=AST
|DDO intermediate-band photometry of moving-group stars.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975PASP...87...17B&db_key=AST
|Luminosities, Temperatures, and Kinematics of K-Type Dwarfs|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJS...22..389E&db_key=AST
|Narrow-and broad-band photometry of red stars. VI. Luminosities and temperatures for old disk-population red stars of high luminosity|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJ...165..317E&db_key=AST
|Narrow-Band and Broad-Band Photometry of Red Stars. III. Southern Giants|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJ...161..199E&db_key=AST
|Stellar Groups in the Old Disk Population|
|Photoelectric determination of the colors of 286 stars south of declination -15 degrees.|