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.
Alpha Centauri is the nearest star system to the Sun, located at a distance of 4.37 light years or 1.34 parsecs from Earth. It is the brightest star in Centaurus constellation and the third brightest star in sky, only slightly brighter than Arcturus in Booetes boÃ¶tes constellation And vega In. lyralpha Centauri is a binary star system consisting of Alpha Centauri A and Alpha Centauri B. It is sometimes referred to as Alpha Centauri AB (Î± Cen AB).