What is 19P/Borrelly?
{{Infobox planet | name=19P/Borrelly | background=#FFE0C2 | image=Comet Borrelly Nucleus.jpg | image_size= 250 | discoverer=[[Alphonse Borrelly]] | discovered=December 28, 1904 | alt_names=1905 II; 1911 VIII; 1918 IV;<br/> 1925 VIII; 1932 IV; 1953 IV;<br/> 1960 V; 1967 VIII; 1974 VII;<br/> 1981 IV; 1987 XXXIII; 1994 XXX | epoch=September 8, 2001 ([[Julian date|JD]] 2452160.5) | semimajor=3.59 [[Astronomical Unit|AU]] | perihelion= 1.35 AU<br />(February 1, 2022)<ref name=MPC>{{mpc|19p}}</ref> | aphelion= 5.83 AU | eccentricity=0.624 | period= 6.8 [[Julian year (astronomy)|a]] | inclination=30.3° | dimensions=8×4×4&nbsp;km<ref name=Weaver2003>{{cite journal |last=Weaver |first=H. A. |author2=Stern, S.A. |author3=Parker, J. Wm. |title=Hubble Space Telescope STIS Observations of Comet 19P/BORRELLY during the Deep Space 1 Encounter |journal=The American Astronomical Society |volume=126 |issue=1 |pages=444–451 |date=2003 |doi=10.1086/375752 |url=http://www.iop.org/EJ/article/1538-3881/126/1/444/202321.text.html |access-date=2008-12-16 |bibcode=2003AJ....126..444W |s2cid=122186063 |archive-date=2020-05-10 |archive-url=https://web.archive.org/web/20200510022534/http://www.iop.org/EJ/article/1538-3881/126/1/444/202321.text.html |url-status=dead }}</ref> |density=0.3 [[Gram|g]]/cm³<ref name=Britt2006>{{cite web |date=2006 |title=Small Body Density and Porosity: New Data, New Insights |publisher=Lunar and Planetary Science XXXVII |author=D. T. Britt |author2=G. J. Consol-magno SJ |author3=W. J. Merline |url=http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2214.pdf |access-date=2008-12-16| archive-url= https://web.archive.org/web/20081217064607/http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2214.pdf| archive-date= 17 December 2008 | url-status= live}}</ref> | mean_radius = 2.4 km<ref>{{Cite web |url=http://solarsystem.nasa.gov/planets/profile.cfm?Object=Com_19PBorrelly&Display=Facts&System=Metric |title=19P/Borrelly: Facts & Figures|access-date=2014-08-08 |archive-url=ht