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.
Sirius A,B-Type= A1 + DA, Magnitudes=-1.4+8.4, Distance=8.60 ly. This brilliant white star is the brightest star in the night sky and the most luminous star within 25 light years. Its white dwarf companion was first seen in 1852, the first white dwarf ever seen.