322P/SOHO

Observational history

The comet was first spotted by Terry Lovejoy after analyzing SOHO imagery on 4 September 1999.

After Kazimieras Černis spotted another SOHO comet in 2003, Sebastian F. Hönig, later determined that both P/1999 R1 and P/2003 R5 might be the same object, where he predicted its return in 2007. His calculations were later proven correct when it was successfully recovered by Bo Zhou as P/2007 R5 after analyzing SOHO images on 10 September 2007. It became one of the first comets that SOHO has discovered that is confirmed to be periodic.

Bo Zhou recovered the comet once again on September 6, 2011. It was observed again in September 2019.

Possible connection with the Great Comet of 254 AD

It has been suggested that 322P/SOHO is associated with a comet observed in November–December 254 AD and is mentioned in East Asian sources to have an extremely long tail. If the association is correct, it is possible that the comet split in 254 AD, resulting in intense cometary activity, but activity decreased afterwards as the comet lost most of its volatiles, and no longer displays a tail or a prominent coma. Current activity is fueled by sodium sublimation.

Physical characteristics

322P/SOHO is either an extinct comet or an active asteroid. Light-curve and infrared observations by Spitzer in 2016 suggest that its nucleus is probably only 150 – in diameter, with a rotation period lasting hours.

Orbit

322P/SOHO is a member of the Kracht sungrazer family of comets. On April 11, 1947 it passed about 7.1 +/- from Earth.

Exploration

On 2 September 2019, NASA's Parker Solar Probe incidentally passed the tail of 322P/SOHO at a distance of 0.012 AU, making direct measurements of the comet as it interacts with the solar wind.

References

| article-number= 116382

| display-authors= 5 | doi-access= free }}

| doi-access= free }}

| access-date= 2007-09-26 | archive-date= 2007-10-11 | archive-url= https://web.archive.org/web/20071011195630/http://news.nationalgeographic.com/news/2007/09/070925-new-comet.html | url-status= dead }}

| access-date= 2023-08-16 }}

| doi-access= free }}

| access-date= 2017-04-10 }}

| access-date= 2012-01-31 | archive-date= 2012-03-03 | archive-url= https://web.archive.org/web/20120303205622/https://sungrazer.nrl.navy.mil/index.php?p=news/the_shy_comet | url-status= dead }}

| access-date= 2025-05-26 }}

| access-date= 2011-09-11 | archive-date= 2013-01-05 | archive-url= https://archive.today/20130105111734/http://tech.groups.yahoo.com/group/sohohunter/message/3444 }}

|access-date=2007-11-19}}

|access-date=2023-08-16}}

|access-date=2023-08-16}} RNG_3sigma = uncertainty range in km. (JPL#10/Soln.date: 2016-Oct-27)

|archive-url=https://web.archive.org/web/20230624014734/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27322P%27&START_TIME=%272023-Aug-20%27&STOP_TIME=%272023-Aug-22%27&STEP_SIZE=%271%20hours%27&QUANTITIES=%2719%27 |archive-date=2023-06-24 |url-status=live |access-date=2023-08-12}} (JPL#10/Soln.date: 2016-Oct-27)

References

1. [https://www.syfy.com/syfywire/the-case-of-the-sun-diving-asteroid-that-thinks-its-a-comet The case of the Sun-diving asteroid that thinks it's a comet] Phil Plait, September 4, 2019