منابع مشابه
Kinematics of Nearby Subdwarfs
A sample of subdwarfs with accurate space velocities and stan-darized metallicities is presented. This was constructed by combining Hip-parcos parallaxes and proper motions with radial velocities and metallicities from Carney et al. (1994; CLLA). The accurate Hipparcos parallaxes lead to an-upward-correction factor of 11% of the photometric distance scale of CLLA. The kinematical behaviour of t...
متن کاملMicroscopic diffusion and subdwarfs
The recent distance determinations by HIPPARCOS have allowed to locate very precisely a reasonable set of subdwarfs in the HR diagram. A detailed comparison with evolutionary models is now possible and it has been recently claimed that the observed lower part of the main-sequence is cooler than the computed one. In this paper we show that microscopic diffusion could be the physical explanation ...
متن کاملDisentangling Composite Spectrum Hot Subdwarfs
We give preliminary results from a spectroscopic study of composite spectrum hot subdwarfs (sd+late-type). We obtained spectra of a sample of hot subdwarfs selected from the Catalogue of Spectroscopically Identified Hot Subdwarfs (Kilkenny, Heber, & Drilling 1988) on the basis of near-infrared pho-tometry from the Two Micron All Sky Survey (2MASS). The sample consists of 20 photometric and spec...
متن کاملsynthesis and characterization of some new cyclometalated organoplatinum(ii) complexes containing phosphite ligand
در این تحقیق روشی جهت سنتز یک سری از کمپلکس های پلاتین (ii) حاوی لیگاند های دهنده ی فسفری شامل فسفیت و فسفین ارائه شده است. واکنش پیش ماده ی پلاتین (ii)،trans/cis- [ptcl2(sme2)2] ، با 2 اکی مولار از لیگاند p(oph)3در حلال بنزن کمپلکس1، cis-[ptcl2(p(oph)3)2] را تولید می نماید. جهت سنتز کمپلکس سایکلو متال فسفیتی، کمپلکس 1 با 1 اکی والان واکنشگر ptcl2 در حلال زایلن در شرایط رفلاکس زیر گاز آرگون م...
Stellar Halo Parameters from 4588 Subdwarfs
Using a reduced proper motion discriminator, I obtain a sample of 4588 subdwarfs from the Revised NLTT Catalog of Salim & Gould. The ample statistics and low contamination permit much more precise determinations of halo parameters than has previously been possible. The stellar halo is not moving with respect to the Local Standard of Rest (LSR) in either the vertical or radial direction, up to u...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1961
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/123.3.273