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 These fairly low mass stars end as white dwarfs made of C and O.  M > 4 Msun: Hot enough to fuse C and O to heavier elements. Very massive stars (massive enough to qualify as supergiants) are able to fuse all the way to iron, the `end of the line' as far as fusion is concerned.