Contents
Images
Upload your image
DSS Images Other Images
Related articles
Constant-Velocity Stars at the North Galactic Pole Suitable for Use as Secondary Velocity Standards
We present mean radial velocities for 143 stars in Selected Area 57 atthe north Galactic pole that are suitable for use as secondary velocitystandards. The stars were drawn from a magnitude-limited sample and aremostly fainter than 11th magnitude in V. They span a wide range ofeffective temperatures and surface gravities and thus provide a suitablesource of targets for observed templates. The mean radial velocities arebased on at least 10 observations spanning at least 8200 days, and areaccurate typically to 0.2 km s-1, with no obvious signs ofvariable velocity or composite spectra.Some of the results presented here used observations made with the MMT,a joint facility of the Smithsonian Institution and the University ofArizona.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| The spectra of G dwarf stars toward the Galactic Poles
Slit spectra of 299 faint, early G dwarf candidates in the directions ofthe North and South Galactic Poles have been classified on the MKsystem. An expediency, employing the normal MK standards, was followedto cope with the 40% of stars which proved to have weak-lined spectra.We present these classifications to show what G dwarf stars in the thickdisk region of the Galaxy are really like spectroscopically. From thewhole spectrum perspective they do resemble the stars of equivalentmetallicity in the solar neighborhood. The spectra of severalinteresting stars are discussed. We also note a tendency for the G-bandstrength to decrease less fast than the overall line weakening in themetal-weak stars.
| A search for wide binaries at the north galactic pole using precise radial velocities
Precise radial velocities are presented from a survey of 247 starscentered on Selected Area 57 at the North Galactic Pole, complete forlate-type stars with V magnitude brighter than 12.0. The radialvelocities have a typical precision of 0.2-0.3 km/s. New spectral typesand distances estimates are presented for 120 of the stars in thesample. All pairs of stars with angular separations between 1 and 600arcsec have been considered, and 11 candidate pairs found with velocitydifferences less than 1.5 km/s. It is estimated that 4 or 5 of the 11candidate pairs are actually bound binaries, but none with separationslarger than 0.1 pc. The constraints imposed by these results on theactual distribution of wide binaries in the Galaxy should now bereanalyzed. The unusual precision of the velocities led to the discoveryof a new cluster associated with the multiple system ADS 8811 ABC.
| Photoelectric V and (B-V) for Weistrop stars near the north Galactic pole
V and (B-V) have been obtained for 173 stars near the north Galacticpole. A comparison is made between these photoelectric values and thephotographic values obtained by Weistrop (1972). Corrections have beenderived which, when applied to (B-V)w and Vw, result in relativelysystematic error-free colors and magnitudes.
| A search for early-G dwarf stars towards the north Galactic pole
A survey for G dwarf stars, which parallels one towards the SouthGalactic Pole, is described. Thin-prism spectra from the Burrell Schmidttelescope were searched for the natural group of F8 to G5 V stars, whichincludes all metallicities. The authors present a candidate list of 192stars, ranging between 11.1 < V < 15.1 in a 3.7 sq. deg area.Photographic UBV magnitudes are included.
| A kinematic and abundance survey at the Galactic poles. III
A sample of 418 space velocities are examined, including 83 new valuesobtained for G5-K6 giants near the North Galactic Pole. A constantDDO-derived Fe/H abundance gradient of about -0.18 dex/kpc is found toextend to 8 kpc. The data show a continuous increase in the velocitydispersion as the distance above the Galactic plane increases and as theDDO-derived Fe/H abundance ratio decreases to -1.00. The data suggest akinematic decoupling of the thick disk and halo stars. As in the case ofthe abundance gradient, the kinematic data are shown to be consistentwith the concept of the galactic-model components. It is noted thatgiants with solar DDO-derived abundances are found only sparsely in thethick disk.
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
Catalogs and designations:
|
INHABITED SKY
