A dwarf star typical of the class to which Nemesis, if it
exists, would belong. |Date of discovery||April 19, 1984
(proposed)| |Name of discoverer||Richard A. Muller| |Name
origin||Greek goddess of retribution| |Semi-major axis||88,000
AU| |Sidereal year||26,000,000 a| |Mass||2 * 10-4 to 7 * 10-2
M☉| |Minimum temperature||2300 K| |Maximum temperature||2600 K|
Background of the Nemesis Hypothesis In 1984, paleontologists
David Raup and Jack Sepkoski published their time-series
analysis of the geologic strata that, according to
uniformitarian geology, were laid down during the last 250
million years. They determined that twelve extinction-level
events (ELEs) had occurred during this time, and that the time
between one ELE and the next was 26 million years. Previous
investigators had linked two of these putative ELEs to large
meteorite impacts. Raup and Sepkoski therefore concluded that
such events (including the alleged extinction of the dinosaurs
65 million years ago) happened regularly and might have an extra