(of stellar atmosphere)
21Model photosphere — Some essential steps in model atmosphere analysis for determining stellar abundances (Figure by Bengt Gustafsson, Astronomical Observatory, Uppsala). The photosphere denotes those solar or stellar surface layers from which optical radiation… …
22Outline of astronomy — Mauna Kea in Hawaii is one of the world s premier observatory sites. Pictured is the W. M. Keck Observatory, an optical interferometer. The following outline is provided as an overview of and topical guide to astronomy: Astronomy – studies the… …
23Eddington luminosity — The Eddington luminosity (also referred to as the Eddington limit) in a star is defined as the point where the gravitational force inwards equals the continuum radiation force outwards, assuming hydrostatic equilibrium and spherical symmetry.… …
24Nucleosynthesis — Nuclear physics Radioactive decay Nuclear fission Nuclear fusion Classical decays …
25Planetary nebula — A planetary nebula is an emission nebula consisting of a glowing shell of gas and plasma formed by certain types of stars when they die. The name originated in the 18th century because of their similarity in appearance to giant planets when… …
26Neptune — This article is about the planet. For other uses, see Neptune (disambiguation). Neptune   …
27Dimitri Mihalas — Dimitri at Spectroscopy and Radiation Hydrodynamics conference in Colorado Nationality American …
28solar system — the sun together with all the planets and other bodies that revolve around it. [1695 1705] * * * The Sun, its planets, and the small bodies (see asteroid, Centaur object, comet, Kuiper belt, meteorite, and Oort cloud) interplanetary dust and gas… …
29V838 Monocerotis — and its light echo as imaged by the Hubble Space Telescope on December 17, 2002. Credit: NASA/ESA Observation data Epoch 2000.0& …
30Fermi paradox — The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations.The extreme age of the universe and its …
