Editing Comet Hale–Bopp (section)

=== Binary nucleus question ===
In 1997 a paper was published that hypothesised the existence of a binary [[comet nucleus|nucleus]] to fully explain the observed pattern of comet Hale–Bopp's dust emission observed in October 1995. The paper was based on theoretical analysis, and did not claim an observational detection of the proposed satellite nucleus, but estimated that it would have a diameter of about {{cvt|30|km|mi}}, with the main nucleus being about {{cvt|70|km|mi}} across, and would orbit in about three days at a distance of about {{cvt|180|km|mi}}.{{r|Sekanina_1997a}} This analysis was confirmed by observations in 1996 using Wide-Field Planetary Camera 2 of the [[Hubble Space Telescope]] which had taken images of the comet that revealed the satellite.{{r|Sekanina_1997a}}

Although observations using [[adaptive optics]] in late 1997 and early 1998 showed a double peak in the brightness of the nucleus,{{r|Marchis_1999}} controversy still exists over whether such observations can only be explained by a binary nucleus.{{r|Fernandez_2002}} The discovery of the satellite was not confirmed by other observations.{{r|McCarthy_2007|Weaver_1999}} Also, while comets have been observed to break up before,{{r|Sekanina_1997b}} no case had been found of a stable binary nucleus until the subsequent discovery of [[P/2006 VW139|{{mp|P/2006 VW|139}}]].