Editing Nemesis (hypothetical star) (section)

==Past, current, and pending searches for Nemesis==
Searches for Nemesis in the infrared are important because cooler stars comparatively shine brighter in infrared light. The [[University of California, Berkeley|University of California]]'s [[Leuschner Observatory]] failed to discover Nemesis by 1986.<ref>{{Cite thesis |degree=Ph.D. |title=An Astrometric Search for a Stellar Companion to the Sun |last=Perlmutter |first=Saul |author-link=Saul Perlmutter |date=1986 |publisher=University of California, Berkeley}}</ref>  The Infrared Astronomical Satellite ([[IRAS]]) failed to discover Nemesis in the 1980s. The [[2MASS]] [[astronomical survey]], which ran from 1997 to 2001, failed to detect a star, or brown dwarf, in the Solar System.<ref name="mullen2010"/> If Nemesis exists, it may be detected by [[Pan-STARRS]] or the planned [[Large Synoptic Survey Telescope|LSST]] astronomical surveys.

In particular, if Nemesis is a [[red dwarf]] or a [[brown dwarf]], the [[WISE mission]] (an infrared sky survey that covered most of the [[solar neighborhood]] in movement-verifying [[parallax]] measurements) was expected to be able to find it.<ref name="mullen2010"/> WISE can detect 150-kelvin brown dwarfs out to 10 [[light-year]]s, and the closer a brown dwarf is, the easier it is to detect.<ref name="browndwarf"/> Preliminary results of the WISE survey were released on April 14, 2011.<ref name=NASA2011-117/> On March 14, 2012, the entire catalog of the WISE mission was released.<ref name="fullrelease"/> In 2014, WISE data ruled out a [[Saturn]] or larger-sized body in the Oort cloud out to ten thousand AU.<ref>[https://www.nasa.gov/press/2014/march/nasas-wise-survey-finds-thousands-of-new-stars-but-no-planet-x/ NASA's WISE Survey Finds Thousands of New Stars, But No 'Planet X']</ref>

Calculations in the 1980s suggested that a Nemesis object would have an irregular orbit due to perturbations from the galaxy and passing stars. The Melott and Bambach work<ref name="melott"/> shows an extremely regular signal, inconsistent with the expected irregularities in such an orbit. Thus, while supporting the extinction periodicity, it appears to be inconsistent with the Nemesis hypothesis, though of course not inconsistent with other kinds of [[substellar object]]s. According to a 2011 NASA news release, "recent scientific analysis no longer supports the idea that extinctions on Earth happen at regular, repeating intervals, and thus, the Nemesis hypothesis is no longer needed."<ref name="Tyche2011-060"/>