BOSTON â President Obama signed an executive order on Monday requiring federal contractors to provide up to seven days of paid sick leave a year, even as he accused Republican congressional leaders of endangering the economy and Republican presidential candidates of undercutting American workers.OSTON â President Obama signed an executive order on Monday requiring federal contractors to provide up to seven days of paid sick leave a year, even as he accused Republican congressional leaders of endangering the economy and Republican presidential candidates of undercutting American workers.
A dwarf star is a star of relatively small size and low luminosity. 1  Most main sequence stars are dwarf stars. The term was originally coined in 1906 when the Danish astronomer Ejnar Hertzsprung noticed that the reddest starsâclassified as K and M in the Harvard scheme could be divided into two distinct groups.
1 A black dwarf is a white dwarf that has cooled sufficiently such that it no longer emits any visible light.  A brown dwarf is a substellar object not massive enough to ever fuse hydrogen into helium, but still massive enough to fuse deuteriumâless than about 0.08 solar masses and more than about 13 Jupiter masses.