The characteristics measured by semen analysis are only some of the factors in semen quality. One source states that 30% of men with a normal semen analysis actually have abnormal sperm function.
Wisps of dust and gas from the nebula which formed the star can also be seen. Credit: Atlas Image courtesy of 2MASS/UMass/IPAC-Caltech/NASA/NSF. Named for the first of their type observed, T Tauri stars are variable stars which show both periodic and random fluctuations in their brightnesses. They are newly-formed (< 10 million years old) low to intermediate mass stars (< 3 solar masses) with central temperatures too low for nuclear fusion to have started.
The primary star of this system is Alpha Centauri A, which is the sun-like star, though bigger and brighter than our Sun. Alpha Cen A is richer in metals and older than our own star. The secondary star is Alpha Centauri B, which is an orange K-type star, meaning it is smaller, dimmer and cooler than our Sun.lpha Centauri system is a system comprising of six planets and three stars, located 4.3 light-years away in the constellation Centaurus in the caelregio Simianus.