Physics Today magazine
Physics Today – 01.01.2018
Physics Today – 01.01.2018.pdf (12.9Mb)
Click Link Below To Download
The outer reaches of the Milky Way, in color. This map is a reconstruction of the total integrated light flux measured by the Gaia space observatory. To date, the European Space Agency, which built, launched, and manages the satellite, has released astrometric measurements of nearly 3 billion stars.
Physics Today – 01.07.2017
best physics magazines
physics today July 2017.pdf
This Hertzsprung–Russell diagram plots the absolute magnitude of some 15 000 white dwarf stars (black dots). Its horizontal axis, as explained in the text, is a proxy for temperature. The more massive a white dwarf, the smaller and less luminous it is. The blue curves illustrate the cooling sequences for three masses of stars (0.6 M⊙, 0.9 M⊙, and 1.1 M⊙, from top to bottom, where M⊙ is the mass of the Sun). The two orange dashed lines delimit the regions where models predict that 20% (top) and 80% (bottom) of the white dwarf masses would crystallize. The liquid-to-solid phase change is accompanied by a release of latent heat that slows the stars’
Physics Today – 01.08.2017
Physics Today – August 2017.pdf
The number of white dwarfs (red dots) per unit luminosity per unit volume versus luminosity L/L⊙for stellar masses 0.9–1.1 M⊙, where L⊙ and M⊙ are the luminosity and mass of the Sun. The number steadily rises as the luminosity falls until the stars cool to less than 1/1000 of the Sun’s luminosity. The plot’s peak in the shaded region is a direct observational signature of crystallization. Three model simulations (black lines) approximate the experimentally observed number of white dwarfs. The best fit (solid line) includes both latent heats released by crystallization and the gravitational energy released by oxygen sedimentation. The dotted curve neglects phase separation but includes latent heat, whereas the dashed curve neglects both.