{"id":16051,"date":"2015-09-20T00:28:46","date_gmt":"2015-09-19T16:28:46","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/the-surface-of-rosettas-comet-is-changing\/"},"modified":"2015-09-20T00:28:46","modified_gmt":"2015-09-19T16:28:46","slug":"the-surface-of-rosettas-comet-is-changing","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/the-surface-of-rosettas-comet-is-changing\/","title":{"rendered":"The surface of Rosetta\u2019s comet is changing"},"content":{"rendered":"
\"This
This sequence of ten images showing changes in the Imhotep region on Comet 67P\/Chruymov-Gerasimenko were taken with the OSIRIS narrow-angle camera on Rosetta between May 24 and July 11, 2015. Credit: ESA\/Rosetta\/MPS for OSIRIS Team MPS\/UPD\/LAM\/IAA\/SSO\/INTA\/UPM\/DASP\/IDA<\/figcaption><\/figure>\n

Views from Europe\u2019s Rosetta comet orbiter show mysterious markings appearing on the nucleus of Comet 67P in recent months, with new surface features forming within a matter of weeks, and scientists are digging into the complex causes of the cometary erosion.<\/p>\n

Heating from the sun likely plays a large role in driving changes on the comet\u2019s nucleus, but the story is more complex, scientists said Friday.<\/p>\n

A sequence of images taken by Rosetta\u2019s OSIRIS camera from May through July reveals fresh round features on the larger lobe of Comet 67P\/Churyumov-Gerasimenko, in a region dubbed Imhotep marked with large boulders and smooth plains that may be covered in granular deposits.<\/p>\n

The Imhotep region, near the comet\u2019s equator, sees prolonged sunlight during each 12.4-hour rotation.<\/p>\n

The changes are more subtle than the brilliant outbursts periodically captured by Rosetta\u2019s camera as Comet 67P passed perihelion, the point in its orbit closest to the sun.<\/p>\n

\u201cWe had been closely monitoring the Imhotep region since August 2014, and as late as May 2015, we had detected no changes down to scales of a tenth of a meter (4 inches),\u201d said Olivier Groussin, an astronomer at the Laboratoire d\u2019Astrophysique de Marseille, France, in a blog post on the European Space Agency\u2019s website.<\/p>\n

\u201cThen one morning we noticed that something new had happened: the surface of Imhotep had started to change dramatically,\u201d said Groussin, a co-investigator on Rosetta\u2019s OSIRIS instrument and lead author of a paper on the discovery to be published in Astronomy and Astrophysics. \u201cThe changes kept going on for quite a while.\u201d<\/p>\n

The first evidence for a new feature in the Imhotep region came in an image captured June 3. By June 13, a second marking appeared nearby, and the two features reached diameters of 220 meters (721 feet) and 140 meters (459 feet) in an image recorded by Rosetta on July 2, according to ESA.<\/p>\n

That is significant growth on a comet that measures 4.1 kilometers (2.5 miles) across on its longest axis.<\/p>\n

A third feature also appeared July 2, and the three disturbances had merged by July 11, with another two new markings showing up.<\/p>\n

ESA said the perimeters of the features progressed across the comet\u2019s surface at a few tens of centimeters per hour, or about one foot per hour \u2014 equivalent to more than 20 feet every day.<\/p>\n

\u201cThis highlights the complexity of the physical processes involved,\u201d Groussin said.<\/p>\n

According to the paper published in Astronomy and Astrophysics, scientists think the markings eroded a depth of up to 5 meters (16 feet) relative to surrounding terrain.<\/p>\n

Volatile molecules just underneath the comet\u2019s outer veneer of dust and rock heat up as it nears the sun. Comet 67P reached perihelion between the orbits of Earth and Mars on Aug. 13.<\/p>\n

As temperatures rise on the airless nucleus, volatiles such as water ice can sublimate \u2014 turning directly from a solid to a gaseous state \u2014 and blow away from the comet.<\/p>\n

Color images from Rosetta may show exposed ice near the rims of the expanding features eating into surrounding material in the Imhotep region, but the markings grow much faster than scientists would expect if the changes were driven only solar heating.<\/p>\n

\"Color
Color images of the newly-found features on Comet 67P appear to show bright reflective areas thought to be exposed water ice. Credit: ESA\/Rosetta\/MPS for OSIRIS Team MPS\/UPD\/LAM\/IAA\/SSO\/INTA\/UPM\/DASP\/IDA<\/figcaption><\/figure>\n

The surface material may be very weak, allowing the features to spread faster, or more exotic chemical processes could aid their growth.<\/p>\n

\u201cWe are looking forward to combining our OSIRIS observations with data from other instruments on Rosetta, to piece together the origin of these curious features,\u201d Groussin said.<\/p>\n

OSIRIS did not see any sign of dust being lofted from the nucleus as the surface markings manifested, but scientists have not ruled out that material eroded by the growing features made its way into space or fell back to the comet.<\/p>\n

Scientists predicted the comet would shed material during perihelion, but the discovery of ongoing erosion in the Imhotep region was the first time Rosetta found clear-cut evidence of surface changes since the spacecraft arrived at Comet 67P in August 2014.<\/p>\n

Rosetta has found evidence of erosion from previous perihelion passages elsewhere on the comet, scientists wrote in the paper describing the discovery.<\/p>\n

\u201cThe dramatic changes observed on Imhotep are a spectacular event, unique to comets, with a currently unpredictable end state,\u201d scientists wrote in Astronomy and Astrophysics. \u201cWe will continue to carefully monitor this region during the coming months to better constrain the erosion processes responsible for these changes. Registering changes on 67P remains a key scientific objective for all Rosetta instruments to better understand how comets work and evolve.\u201d<\/p>\n

Email the author.<\/i><\/b><\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

This sequence of ten images showing changes in the Imhotep region on Comet 67P\/Chruymov-Gerasimenko were taken with the OSIRIS narrow-angle camera on Rosetta between May 24 and July 11, 2015. Credit: ESA\/Rosetta\/MPS for OSIRIS Team MPS\/UPD\/LAM\/IAA\/SSO\/INTA\/UPM\/DASP\/IDA Views from Europe\u2019s Rosetta comet orbiter show mysterious markings appearing on the nucleus of Comet 67P in recent months, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[3098,2423,831,3373],"class_list":["post-16051","post","type-post","status-publish","format-standard","hentry","category-news","tag-comet-67p-churyumov-gerasimenko","tag-comets","tag-european-space-agency","tag-rosetta"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16051"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=16051"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/16051\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=16051"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=16051"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=16051"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}