منابع مشابه
ASTRONOMY AND ASTROPHYSICS Properties of He - rich stars I . Their
A determination of the surface gravity and an abundance analysis of helium in a sample of 17He-rich and 5 normal, reference stars is presented. These results are derived from low resolution CCD spectra, but each star was measured at least 6 times in order to obtain a significant average spectrum for the spectroscopic variables. The helium abundances derived from the models used are very close t...
متن کاملAstronomy & Astrophysics Young stars and protostellar cores near NGC 2023
Context. We investigate the young (proto)stellar population in NGC 2023 and the L 1630 molecular cloud bordering the h ii region IC 434, using Spitzer IRAC and MIPS archive data, JCMT SCUBA imaging and spectroscopy as well as targeted BIMA observations of one of the Class 0 protostars, NGC 2023 MM 1. Aims. We study the distribution of gas, dust and young stars in this region to see where stars ...
متن کاملASTRONOMY AND ASTROPHYSICS Moments of inertia of relativistic magnetized stars
We consider principal moments of inertia of axisymmetric, magnetically deformed stars in the context of general relativity. The general expression for the moment of inertia with respect to the symmetric axis is obtained. The numerical estimates are derived for several polytropic stellar models. We find that the values of the principal moments of inertia are modified by a factor of 2 at most fro...
متن کاملASTRONOMY AND ASTROPHYSICS uvby Photometry of stars with planets
The use of Strömgren uvby photometry is proposed as a simple tool for the estimation of effective temperatures and metallicities in stars discovered to have planets. Previous photometric calibrations are tested with available spectroscopic measurements and their application to stars without high-resolution spectroscopy allowed the determination of metal abundances for 12 additional stars with p...
متن کاملBaltic Astronomy BINARY CENTRAL STARS OF PLANETARY NEBULAE
This paper reviews our knowledge on binary central stars of planetary nebulae and presents some personal opinions regarding their evolution. Three types of interactions are distinguished: type I, where the binary companion induces the mass loss; type II, where it shapes the mass loss but does not enhance it; type III, where a wide orbit causes the centre of mass to move, leading to a spiral emb...
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ژورنال
عنوان ژورنال: Journal of Skyscape Archaeology
سال: 2018
ISSN: 2055-3498,2055-348X
DOI: 10.1558/jsa.36095