31P/Schwassmann–Wachmann

{{Short description|Periodic comet with 8 year orbit}}

{{Infobox comet

| name=31P/Schwassmann–Wachmann

| image= 31P 2011-02-14 PTF ImageDownload-4-irsakuops-ptf-5f5c5ffb54-wpzq9---1 crop.png

| discoverer= Arnold Schwassmann

Arno Arthur Wachmann

| discovery_date=January 17, 1929

| designations=1929 I; 1935 III; 1942 I;
1948 VII; 1955 I; 1961 VII;
1968 II; 1974 XIII; 1981 VI;
1987 XIX; 1994 II

| epoch=March 6, 2006

| semimajor=4.232 AU

| perihelion=3.416 AU

| aphelion=5.048 AU

| eccentricity=0.1928

| period=8.705 a

| inclination= 4.5487°

| last_p=July 6, 2019
September 29, 2010
January 18, 2002{{cite web

|date=2008-10-26

|title=31P/Schwassmann-Wachmann 2

|publisher=Seiichi Yoshida's Comet Catalog

|author=Seiichi Yoshida

|url=http://www.aerith.net/comet/catalog/0031P/index.html

|access-date=2010-01-24}}

| next_p=2028-03-19{{cite web

|title=31P/Schwassmann-Wachmann Orbit

|url=http://www.minorplanetcenter.net/db_search/show_object?object_id=31P

|publisher=Minor Planet Center

|access-date=2020-06-29}}

|caption=Comet 31P/Schwassmann-Wachmann observed on February 14, 2011}}

31P/Schwassmann–Wachmann, also known as Schwassmann–Wachmann 2, is a periodic comet in the Solar System. It was discovered on January 17, 1929, at an apparent magnitude of 11.{{cite web |first=Gary W |last=Kronk |title=31P/Schwassmann–Wachmann 2 |url=http://cometography.com/pcomets/031p.html |access-date=2010-01-24}} ([http://cometography.com Cometography Home Page]) The comet has been seen at every apparition.

The comet nucleus is estimated to be 6.2 kilometers in diameter.{{cite web

|type=2010-01-21 last obs

|title=JPL Small-Body Database Browser: 31P/Schwassmann–Wachmann 2

|url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=31P

|publisher=Jet Propulsion Laboratory

|access-date=2010-02-26}} In 1929, the astronomer Anne Sewell Young identified the comet with an object that had been misidentified as the minor planet "Adelaide" (A904 EB).{{cite news|title=Long 'Lost' Planet Found Masquerading as Comet|url=https://www.newspapers.com/clip/14987519/anne_sewell_young_18711961/|newspaper=Oakland Tribune|date=June 21, 1929|page=31|via = Newspapers.com|access-date = November 9, 2017}} {{Open access}}