منابع مشابه
Milky Way
7 Globular clusters and Population II stars are fossil remnants of the first major epoch of star formation in the Milky Way. SIM Lite will determine precise distances to selected Pop II objects to define a reliable distance scale, and establish reliable absolute and relative ages. Those ages set a minimum age for the Universe and map the early formation history of the Milky Way. The resultant a...
متن کاملMilky Way Gas Dynamics
The Milky Way is made up of a central bar, a disk with embedded spiral arms, and a dark matter halo. Observational and theoretical constraints for the characteristic parameters of these components will be presented, with emphasis on the constraints from the dynamics of the Milky Way gas. In particular, the fraction of dark matter inside the solar radius, the location of the main resonances, and...
متن کاملAntimatter in the Milky Way
Observational signatures of existence of antimatter objects in the Galaxy are discussed. We focus on point-like sources of gamma radiation, diffuse galactic gamma ray background and anti-nuclei in cosmic rays.
متن کاملMilky Way Rotation from Cepheids
The 87 new 0 determinations were added to the existing sample of cepheids with known radial velocities, forming an extended sample of 278 galactic classical cepheids with reliable radial velocity and photometry. We then calculated distances for these objects through a Period-Luminosity-Colour relation due to Feast & Walker (1987). The position of the cepheids in the galactic disk as given by th...
متن کاملTwo New Milky Way Companions
We discuss the detection limits and current status of a uniform survey of SDSS I for ultra-faint Milky Way dwarf galaxies. We present the properties of two new, low surface brightness Milky Way companions discovered as a result of this survey. One of these companions is the Ursa Major dwarf, the newest dwarf spheroidal companion to the Milky Way and the lowest luminosity galaxy yet known. Ursa ...
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ژورنال
عنوان ژورنال: Nature
سال: 1991
ISSN: 0028-0836,1476-4687
DOI: 10.1038/353496b0