منابع مشابه
ar X iv : a st ro - p h / 01 10 34 0 v 1 1 5 O ct 2 00 1 5 - micron photometry of late - type dwarfs
We present narrowband-M photometry of nine low-mass dwarfs with spectral types ranging from M2.5 to L0.5. Combining the (L-M) colours derived from our observations with data from the literature, we find colours consistent with a Rayleigh-Jeans flux distribution for spectral types earlier than M5, but enhanced F3.8 F4.7 flux ratios (negative (L-M) colours) at later spectral types. This probably ...
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We analyse the formation of He I lines in late-type dwarfs by statistical equilibrium (or NLTE radiative transfer) computations. Atmospheric models for dK (Eri) and dMe V1005Ori (=Gl 182) stars are considered. The validity of the weakly non-uniform approximation for dMe stars established in Lanzafame (1994a) for the lower transition region of dMe stars implies that streaming particles have virt...
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Using a self-consistent dynamic theory of non-local convection, the atmospheric lithiumabundance depletion values of a series of stellar evolutionary models withM = 0.725–1.5 M are calculated, and the results show that the general observed properties of lithium abundance in lower-main-sequence stars can be reproduced by overshooting mixing and gravitational settling. After a careful study of th...
متن کاملB and R CCD surface photometry of late - type galaxies
We present B and R CCD observations of 16 latetype galaxies, mainly Magellanic irregulars and blue compact galaxies, at a limiting surface brightness of μB ∼ 26–27 mag arcsec−2. The sample is derived from a H I-rich subset of an H I survey of late-type dwarfs and consists of objects with – 19.5≤MB ≤–14.4, nine galaxies being fainter than MB=–17 (H0=75 km s−1 Mpc−1). Radial luminosity distributi...
متن کاملPhotometry of Southern , Extreme Late - Type Spiral Galaxies
We present B and V CCD aperture photometry for a morphologically-selected sample of forty-nine southern, extreme late-type spiral galaxies. All objects are moderate-to-low surface brightness Local Supercluster field galaxies that were detected previously in H i surveys. Our sample features objects that have optical luminosities, optical sizes, and H i masses which are at the low end for spiral ...
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ژورنال
عنوان ژورنال: The Astronomical Journal
سال: 2002
ISSN: 0004-6256,1538-3881
DOI: 10.1086/338083