Small periodic shift of the apparent positions of nearby stars due to the changing position of the Earth as it orbits the Our parent star. The structure of Sun's interior is the result of the hydrostatic equilibrium between gravity and the pressure of the gas. The interior consists of three shells: the core, radiative region, and convective region. Image source: http://eclipse99.nasa.gov/pages/SunActiv.html. The core is the hot, dense central region in which the. The nearer the Self-luminous object held together by its own self-gravity. Often refers to those objects which generate energy from nuclear reactions occurring at their cores, but may also be applied to stellar remnants such as neutron stars. is, the larger the shift. The distance to stars in parsecs is simply 1/parallax, (or in light years it is 3.2616 divided by the parallax) where the parallax is in Measure for very small angles ("). 1 arcsecond = 1/60 arcminute = 1/3600 degree..
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