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The Solar Neighborhood. XXV. Discovery of New Proper Motion Stars with 0farcs40 yr-1 > ? >= 0farcs18 yr-1 between Declinations -47° and 00°
We present 2817 new southern proper motion systems with 0farcs40yr-1 > ? >= 0farcs18 yr-1 and declinationbetween -47° and 00°. This is a continuation of theSuperCOSMOS-RECONS (SCR) proper motion searches of the southern sky. Weuse the same photometric relations as previous searches to providedistance estimates based on the assumption that the objects are singlemain-sequence stars. We find 79 new red dwarf systems predicted to bewithin 25 pc, including a few new components of previously knownsystems. Two systems—SCR 1731-2452 at 9.5 pc and SCR 1746-3214 at9.9 pc—are anticipated to be within 10 pc. We also find 23 newwhite dwarf (WD) candidates with distance estimates of 15-66 pc, as wellas 360 new red subdwarf candidates. With this search, we complete theSCR sweep of the southern sky for stars with ? >= 0farcs18yr-1 and R 59F <= 16.5, resulting in a totalof 5042 objects in 4724 previously unreported proper motion systems.Here we provide selected comprehensive lists from our SCR proper motionsearch to date, including 152 red dwarf systems estimated to be within25 pc (9 within 10 pc), 46 WDs (10 within 25 pc), and 598 subdwarfcandidates. The results of this search suggest that there are morenearby systems to be found at fainter magnitudes and lower proper motionlimits than those probed so far.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| The general catalogue of trigonometric [stellar] paralaxes
Not Available
| Subdwarf studies. I - UBVRI photometry of NLTT stars
UBVRI photometry is presented for a sample of 1656 southern stars,including 1211 that were previously unmeasured, drown from the NLTTproper-motion catalog. The catalog is shown to be a rich source ofsubdwarfs. The normalized ultraviolet excess delta (U - B)0.6,photometric parallax, and interstellar reddening are calculated for eachstar when possible. Photometric parallaxes are compared withtrigonometric parallaxes from the literature. It is found that theformer do not have systematic errors greater than about 25 percent. Inagreement with other studies, the bluest subdwarfs are found at B - V =0.35. The selection of the program stars on the basis of large reducedproper motions restricted subgiant contamination of the sample to about5 percent and increased the discovery fraction of halo stars relative todisk stars. The claim is made here that the sample can be used toinvestigate the abundance distribution of the halo. The sample includesstars with ultraviolet excesses characteristic of disk abundances butwith velocities up to 150 km/s. These are believed to be stars that,quite expectedly, reside in the high-velocity tail of the disk velocitydistribution.
| Four-color UVBY and H-beta photometry of high-velocity and metal-poor stars. I - The catalogue of observations
A catalog of four-color uvby and H-beta photometry for 711 high-velocityand metal-poor stars is given. The selection of the stars and theobserving and reduction techniques used to obtain these data arediscussed. The photometry has been transformed closely onto the standarduvby-beta system. The errors of the data have been estimated using bothinternal and external comparisons. The data are uniform over the sky;that is, there are no significant north-south differences. For the largemajority of stars the mean errors of V, m1, c1, and beta are less than +or - 0.008 mag, and the error of b-y is less than + or - 0.005 mag.Values of V, b-y and beta and rough photometric classifications aregiven for 63 red and/or evolved stars that fall outside the range of thephotometric transformations.
| Population studies. II - Kinematics as a function of abundance and galactocentric position for (Fe/H) of -0.6 or less
A catalog is presented of some 1200 Galactic objects which have radialvelocities and (Fe/H) abundances of -0.6 or less. These data areanalyzed to yield information on the kinematic properties of the olderpopulations of the Galaxy and on the interdependence between kinematicsand abundance. It is found that the kinematics of the availablekinematically selected stars differ from those of the nonkinematicallyselected objects. No evidence is found for any significant difference inthe kinematic properties of the various halo subgroups, nor for anydependence of kinematics on abundance. While the rotation of the halo issmall at about 37 km/s for (Fe/H) of -1.2 or less, it rises quickly forhigher abundances to a value of about 160 km/s at (Fe/H) = 0.6. Objectsin the abundance range -0.9 to -0.6 appear to belong predominantly to apopulation possessing the kinematic characteristics of a thick disk. Theimplications of these findings for the suggestion that globular clustersbelong to the same population as the noncluster objects, for the originof the thick disk, and for the mass of the Galaxy are discussed.
| The subdwarf helium abundance and the rotation of the galactic halo
Temperatures, barometric corrections, and metallicities for eightsubdwarfs with good trigonometric parallaxes and 10 Hyades dwarfs areused to determine that subdwarfs lie well below the Hyades in theluminosity-temperature diagram. The subdwarf locus is compared to thetheoretical isochrones of Ciardullo and Demarque to derive a subdwarfhelium mass fraction. The adopted distance callibration is used toinvestigate the kinematics of the subdwarfs. Upon adopting 250 km/s asthe rotational velocity of the local standard of rest about the galacticcenter, several subdwarfs were found to be moving in retrograde orbitswhile others were moving in direct circular orbits exceeding 400 km/s.
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Группы:
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Наблюдательные данные и астрометрия
| Созвездие: | Центавр |
| Прямое восхождение: | 11h06m54.00s |
| Склонение: | -46°10'15.9" |
| Видимая звёздная величина: | 11.211 |
| Собственное движение RA: | -239.7 |
| Собственное движение Dec: | -56.6 |
| B-T magnitude: | 11.723 |
| V-T magnitude: | 11.254 |
Каталоги и обозначения:
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